Insulin increases placental triglyceride as a potential mechanism for fetal adiposity in maternal obesity

OBJECTIVE

Maternal obesity increases the incidence of excess adiposity in newborns, resulting in lifelong diabetes risk. Elevated intrauterine fetal adiposity has been attributed to maternal hyperglycemia; however, this hypothesis does not account for the increased adiposity seen in newborns of mothers with obesity who have euglycemia. We aimed to explore the placental response to maternal hyperinsulinemia and the effect of insulin-like growth factor 2 (IGF-2) in promoting fetal adiposity by increasing storage and availability of nutrients to the fetus.

METHODS

We used placental villous explants and isolated trophoblasts from normal weight and obese women to assess the effect of insulin and IGF-2 on triglyceride content and insulin receptor signaling. Stable isotope tracer methods were used ex vivo to determine effect of hormone treatment on de novo lipogenesis (DNL), fatty acid uptake, fatty acid oxidation, and esterification in the placenta.

RESULTS

Here we show that placentae from euglycemic women with normal weight and obesity both have abundant insulin receptor. Placental depth and triglyceride were greater in women with obesity compared with normal weight women. In syncytialized placental trophoblasts and villous explants, insulin and IGF-2 activate insulin receptor, induce expression of lipogenic transcription factor SREBP-1 (sterol regulatory element-binding protein 1), and stimulate triglyceride accumulation. We demonstrate elevated triglyceride is attributable to increased esterification of fatty acids, without contribution from DNL and without an acceleration of fatty acid uptake.

CONCLUSIONS

Our work reveals that obesity-driven aberrations in maternal metabolism, such as hyperinsulinemia, alter placental metabolism in euglycemic conditions, and may explain the higher prevalence of excess adiposity in the newborns of obese women.

Insulin Regulates Glycogen Synthesis in Human Endometrial Glands Through Increased GYS2

CONTEXT

Glycogen synthesis is a critical metabolic function of the endometrium to prepare for successful implantation and sustain embryo development. Yet, regulation of endometrial carbohydrate metabolism is poorly characterized. Whereas glycogen synthesis is attributed to progesterone, we previously found that the metabolic B isoform of the insulin receptor is maximally expressed in secretory-phase endometrium, indicating a potential role of insulin in glucose metabolism.

OBJECTIVE

We sought to determine whether insulin or progesterone regulates glycogen synthesis in human endometrium.

DESIGN, PARTICIPANTS, OUTCOME MEASUREMENTS

Endometrial epithelial cells were isolated from 28 healthy women and treated with insulin, medroxyprogesterone (MPA), or vehicle. Intracellular glycogen and the activation of key enzymes were quantified.

RESULTS

In epithelia, insulin induced a 4.4-fold increase in glycogen, whereas MPA did not alter glycogen content. Insulin inactivated glycogen synthase (GS) kinase 3α/β (GSK3α/β), relieving inhibition of GS. In a regulatory mechanism, distinct from liver and muscle, insulin also increased GS by 3.7-fold through increased GS 2 (GYS2) gene expression.

CONCLUSIONS

We demonstrate that insulin, not progesterone, directly regulates glycogen synthesis through canonical acute inactivation of GSK3α/β and noncanonical stimulation of GYS2 transcription. Persistently elevated GS enables endometrium to synthesize glycogen constitutively, independent of short-term nutrient flux, during implantation and early pregnancy. This suggests that insulin plays a key, physiological role in endometrial glucose metabolism and underlines the need to delineate the effect of maternal obesity and hyperinsulinemia on fertility and fetal development.

Time course analysis of RNA quality in placenta preserved by RNAlater or flash freezing

PROBLEM

Preservation of biospecimen quality is critical to accurately and reliably assessing genes and proteins. We evaluated the effect of preparation method and storage duration on RNA quality in placenta and decidua.

METHOD OF STUDY

Aliquots of nine placentas and decidua were placed in RNAlater^® (RL) or flash frozen (FF) within 30 minutes of delivery. RNA was extracted immediately (baseline) and from matched samples stored at -80°C for 1 and 8-10 months. RNA Integrity Number (RIN) and housekeeping gene expression were quantified.

RESULTS

At both time points, RL placenta had RIN and housekeeping gene Ct values similar to baseline. However, FF placenta had significantly lower RIN and higher Ct values at 1 and 8-10 months. In RL and FF decidua, RIN was unchanged from baseline.

CONCLUSION

We found RNAlater more effectively and consistently preserved placenta, compared to flash freezing. However, for decidua, which is less dense than placenta, both modes yielded comparable RNA integrity over time.

Performance of dairy cows fed annual ryegrass silage and corn silage with steam-flaked or ground corn

Twenty-four lactating Holstein cows were used in a 6-wk randomized block design trial with a 2 x 2 factorial arrangement of treatments to determine the effects of feeding ground corn (GC) or steam-flaked corn (SFC) in diets based on either annual ryegrass silage (RS) or a 50:50 blend of annual ryegrass and corn silages (BLEND). Experimental diets contained 49.6% forage and were fed as a total mixed ration once daily for 4 wk after a 2-wk preliminary period. No interactions were observed among treatments. Cows fed BLEND consumed more dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) than those fed RS, but total-tract digestibility of OM, NDF, and ADF was greater for RS than for BLEND. No differences in nutrient intake were observed among treatments during wk 4 when nutrient digestibility was measured, but digestibility of DM and OM was greater for SFC than for GC. Cows fed BLEND tended to produce more energy-corrected milk than those fed RS, resulting in improved efficiency (kg of milk per kg of DM intake). When diets were supplemented with SFC, cows consumed less DM and produced more milk that tended to have lower milk fat percentage. Yield of milk protein and efficiency was greatest with SFC compared with GC. Blood glucose and milk urea nitrogen concentrations were similar among treatments, but blood urea nitrogen was greater for cows fed GC compared with those fed SFC. Results of this trial indicate that feeding a blend of annual ryegrass and corn silage is more desirable than feeding diets based on RS as the sole forage. Supplementing diets with SFC improved performance and efficiency compared with GC across forage sources.

Performance and ruminal fermentation of dairy cows fed whole cottonseed with elevated concentrations of free fatty acids in the oil

Twenty-four lactating Holstein cows were used in an 8-wk completely randomized design trial to examine the effects of feeding whole cottonseed (WCS) with elevated concentrations of free fatty acids (FFA) in the oil on intake and performance. Treatments included WCS with normal concentrations of FFA (6.8%, control) and 2 sources of WCS with elevated FFA [HFFA1 (24.1%) or HFFA2 (22.3%)]. The 2 sources of WCS with elevated FFA differed in that HFFA2 were discolored from being initially stored with excess moisture, which led to heating and deterioration during storage, whereas HFFA1 were normal in appearance and the increase in FFA occurred without heating and visible damage to the WCS. Nutrient concentrations were similar among WCS treatments, which provided 14% of the total dietary dry matter. Dry matter intake tended to be higher for cows fed HFFA2 compared with control and HFFA1. Yield of milk and components was similar among treatments, but milk fat percentage was lower for HFFA1 and HFFA2 compared with control. In a concurrent 3 x 3 Latin square trial with 6 ruminally cannulated Holstein cows, molar proportions of isobutyrate were higher for HFFA2 than control and HFFA1, but no differences were observed in acetate or propionate. Results of these trials indicate that feeding WCS with high concentrations of FFA decreases milk fat percentage but does not alter dry matter intake, milk yield, or concentrations of other components. The minor changes in ruminal fermentation that were observed do not account for the decrease in milk fat percentage.

Performance of Lactating Dairy Cows Fed Whole Cottonseed Coated with Gelatinized Starch plus Urea or Yeast Culture

Thirty lactating Holstein cows were used in an 8-wk randomized design trial to test the viability of select additives included in the gelatinized corn starch coating applied to whole cottonseed (WCS) on nutrient intake and digestibility and milk yield and composition. Treatments included WCS coated with 2.5% gelatinized corn starch (control); control plus 0.5% urea; or control plus 2.0% yeast culture. The treated WCS represented 12.6% of the dietary dry matter. Cellulose intake was lower for the control coating compared with either the urea or yeast coating because of slightly lower cellulose concentrations in the control treatment. Intake of all other nutrients was similar for all treatments. Whole-tract nutrient apparent digestibility was not altered by treatment. Dry matter intake and milk yield were similar among treatments. Percentage solids-not-fat was lower for the yeast treatment compared with control, but no other differences were observed in milk composition among treatments. Efficiency of milk production (energy-corrected milk yield per unit of dry matter intake) was higher for the urea and yeast treatments compared with control because of slightly higher yield of milk fat and energy-corrected milk. No differences were observed in body weight change during the trial between treatments. Results of this trial indicate that including urea or yeast culture in the gelatinized starch coating does not change whole tract digestibility, but does improve milk production efficiency.

Effect of Length of Cut and Kernel Processing on Use of Corn Silage by Lactating Dairy Cows

Forty Holstein cows were used in an 8-wk randomized block design trial to determine the effects of theoretical length of cut (TLC) and kernel processing (KP) of whole plant corn silage on nutrient intake and digestibility, milk yield, and milk composition. Corn was harvested at three-quarters milk line stage of maturity at TLC of 1.90 or 2.54 cm. At each TLC, corn was KP at either 2 or 8 mm roll clearance. The control was harvested at 1.90 cm without KP. Corn silage provided 38% of the dietary dry matter (DM) in the experimental diets. Intake of DM and nutrients was similar among treatments. Apparent digestibility of DM and acid detergent fiber (ADF) increased with increasing TLC. Fiber digestibility was improved by KP compared with unprocessed corn silage. Starch digestibility was greater for corn silage KP at 2 vs. 8 mm. Apparent digestibility of DM, crude protein, and ADF was lowest for the diet containing silage harvested at 2.54 cm TLC and KP at 8 mm, resulting in an interaction of TLC and KP. No differences were observed in DM intake (DMI) among treatments. An interaction of TLC and KP was observed, however, for yield of milk protein and energy-corrected milk (ECM) and efficiency of converting DMI to ECM because of lower yield for diets containing silage harvested at 2.54 cm TLC and KP at 8 mm. Results of this trial indicate that as TLC increases, aggressive KP is necessary to maintain nutrient digestibility and performance of lactating dairy cows.

Use of capillary gas chromatography with negative ion-chemical ionization mass spectrometry for the determination of perfluorocarbon tracers in the atmosphere

A sensitive and selective technique for the quantitative measurement of atmospheric perfluorocarbon trace species at the sub part per quadrillion (10(-15)) levels is presented. The method utilizes advances in adsorbent enrichment techniques coupled with benchtop capillary gas chromatography and negative ion-chemical ionization mass spectrometry. The development and enhancement of sampling technology for tracer experiments is described, and the results from background measurements and a preliminary field experiment are presented. The overall precision of the analytical method with respect to the preferred tracer for these atmospheric transport studies, perfluoromethylcyclohexane, was +/-1.7%. The background concentrations of perfluorodimethylcyclobutane, perfluoromethylcyclopentane, and perfluoromethylcyclohexane at a remote coastal location (Mace Head, Ireland, 53 degrees N, 10 degrees W) were found to be 2.5 (+/-0.4), 6.8 (+/-1.0), and 5.2 fL L(-1) (+/-1.3), respectively. Background concentrations within an urban conurbation (Bristol, U.K.) were slightly greater at 3.0 (+/-1.5), 8.1 (+/-1.8), and 6.3 fL L(-1) (+/-1.1), respectively.

A procedure for withdrawal of sleep medication in elderly women who have been long-term users

A program for withdrawal of sedative/hypnotic medication was investigated in elderly women, ages 64 to 91. The sleep cycles of 10 drug withdrawal (DW) and 10 non-drug withdrawal (N-DW) subjects were monitored for a 24-hour period for 5 successive weeks, using a nonintrusive recording procedure. The first 2 baseline weeks were followed by 1 week of half-dose, then 2 weeks of full withdrawal for the DW group. The results indicated no demonstrable effect on sleep, sleep complaints, levels of depression, or daytime sleepiness on the DW group. The conclusion is that the procedure of withdrawal from sleep medication over a 2-week period, combined with the use of a substitute pill to maintain the ritual of nightly pill-taking, is appropriate and effective for long-term elderly users.

The effects of evening light exposure on the sleep of elderly women expressing sleep complaints

In order to address the typical phase advanced, disturbed sleep of the elderly, additional evening light was provided to elderly women by means of a "visor" which provides 2000 lux to each eye. The subjects wore the light visor for 30 min in the evening. The subjects were 10 community-residing women over the age of 65 (mean = 79.4 years; range, 67-87 years). Sleep was recorded in the home for 28 successive 24-hr periods: 7 days pretreatment, 14 days while using the light visor, and 7 days posttreatment. Thus, each subject served as her own control. Sleep was recorded using the Home Monitoring System (HMS), a nonintrusive procedure which does not require instrumentation of the subject. The subjects showed significant changes during and even after the intervention: there was a significant decrease in sleep latency over weeks, and a significant increase in sleep time and sleep efficiency. The subjects also reported less fatigue during treatment. The results suggest that additional light, provided for as little as 0.5 hr in the evening and at only 2000 lux, increases the amount of nighttime sleep and improves the quality of sleep in older women.

Oral capture and grasping of an artificial nipple by rat fetuses

Although born blind and deaf, newborn rats exhibit a remarkable capacity to recognize and gain access to the nipples of the lactating mother. However, it is well-known that full-term rat neonates will not attach to an artificial nipple. In the present study, an artificial nipple fashioned from soft vinyl was presented to rat fetuses from E17-E21 of gestation. Fetuses showed side-to-side head movements that resulted in oral capture of the nipple on E18 and exhibited a direct nipple-grasping response from E19 through term. Frame-by-frame analysis of videotape records of E21 rat fetuses revealed that tactile contact with the artificial nipple elicited mouthing, licking directed at the nipple, forelimb treadling, and grasping of the nipple. Fetuses also exhibited components of aversive behavior, including facial wiping and head turning, that appeared to terminate oral contact with the nipple. Morphine pretreatment reduced the expression of aversive responses and promoted licking and grasping of the artificial nipple. In addition to documenting the prenatal ontogeny of this important neonatal behavior, these findings imply a role for endogenous opioids in the newborn rat's first suckling episode.

Imaging paediatric endocrine disorders

Disorders of growth and development, including delayed and precocious puberty may be idiopathic, constitutional or due to a disorder of one of several endocrine systems including the hypothalamic-pituitary system, the adrenal and the thyroid. Sonography is of great importance in the classification of precocious puberty in children. Skeletal maturation assessment is useful to evaluate the severity of the growth disorder and to monitor subsequent therapy. Magnetic resonance imaging and computed tomography are essential in the study of the pituitary and central nervous system. MRI has special advantages in the imaging of the hypothalamic-pituitary region. The thyroid gland and its function are still best imaged with radionuclide scintigraphy. Sonography can play a complementary though less important role. Hypoparathyroidism, pseudohypoparathyroidism and pseudopseudohypoparathyroidism although rare are more common in children than primary hyperparathyroidism. Valuable clues as to the presence of these conditions can be gained by examination of the plain radiographs. Confirmation of their diagnosis still rests with the biochemical and endocrine profile.

Blood pressure and its relationship to low levels of alcohol consumption

The association between average weekly alcohol consumption and blood pressure was studied in relation to age, adiposity and smoking in 13 535 men and 7385 women. There was a progressive increase in blood pressure with increasing alcohol consumption, even at low levels of consumption.

Alcohol consumption and blood pressure: survey of the relationship at a health-screening clinic

We studied the association between stated alcohol consumption and blood pressure, making allowance for age, adiposity and smoking in 13535 men and 7385 women who were not receiving antihypertensive treatment. They represented a wide cross-section of the inner Sydney working population with 95% aged between 18 and 70. We found a high degree of linear correlation between stated alcohol consumption and blood pressure, diastolic and systolic. This relationship was independent of age, adiposity and smoking. For each 100 g/week increase in stated alcohol consumption, diastolic blood pressure increased by 0.12 kPa (0.92 mmHg) in men and by 0.20 kPa (1.5 mmHg) in women; no threshold for this effect was evident. A plateau appeared at about 500 g/week. Blood pressure increased significantly with age and adiposity (Quetelet's index). Smoking was associated with a lower diastolic blood pressure. The difference in mean diastolic blood pressure between smokers and non-smokers was 0.20 kPa (1.5 mmHg) for men and 0.27 kPa (2.1 mmHg) for women.