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.

Update on Osteoporosis Screening and Management

Osteoporosis is a metabolic bone disease characterized by low bone mass and microarchitectural deterioration of bone tissue leading to an increased risk of fragility fractures. Central dual-energy X-ray absorptiometry measurements are the gold standard for determining bone mineral density. A well-balanced diet containing adequate amounts of calcium and vitamin D, exercise, smoking cessation, and limited alcohol intake are important to maintain bone health. Pharmacologic agents should be recommended in postmenopausal women who are at high risk for fractures. Newer anabolic therapies including teriparatide, abaloparatide, and romosozumab have emerged for use in severe osteoporosis.

OR20-07 Placentas from Obese Women Are Resistant to the Effect of Insulin on Triglyceride Content Ex Vivo

Background: Obesity affects 25% of pregnant women and is associated with a higher risk of neonatal complications, such as macrosomia and increased adiposity. The placenta may contribute to neonatal adiposity by accumulating and transferring excess lipid in response to maternal hyperinsulinemia. We previously found that insulin promotes a 3-fold increase in placental triglyceride (TG) content in lean women. We hypothesized that obese women have higher placental insulin resistance compared to lean women[FC1] with respect to TG content. Methods: Healthy, lean women (n=12; mean age 34±1 yrs; BMI 22±0.4 kg/m²) and non-diabetic, obese women (n=9; mean age 32±2 yrs; BMI 33±0.4 kg/m², p<0.0001) consented for placenta collection at elective c-section under fasting conditions. Placental villous explants were immediately flash frozen or cultured for 24 hours, starved, then treated for 48 hours with 0.1nM, 1nM, 10nM, or 100nM of insulin, or vehicle. Lipids were extracted from basal and treated explants using a chloroform-methanol separation protocol. TG content was quantified by spectrophotometer and normalized to weight. Data were analyzed by two-way ANOVA. Results: Basal placenta tissue from obese women contained a 1.5-fold higher level of TG compared to lean women (9.4±0.5 vs 5.7±0.5 mcg/mg, p=0.001). Placental response to insulin in lean women peaked at 1nM insulin (20.2±3.3 mcg/mg), and plateaued at higher doses of 10nM (18.6±3.3 mcg/mg) and 100nM (22.8±2.8 mcg/mg, p=NS respectively). In contrast, placenta explants from obese women required the highest insulin dose of 100 nM for maximal response (23.6±3.2 mcg/mg), and showed a gradual dose response from 0.1 nM insulin (9.5±2), 1nM (14.8±2), 10 nM (16.9±3). At 100nM insulin, the difference in TG content was variable, but on average was 2-fold higher than vehicle treated placenta (vs 11.8±2.5[FC2] [AA3] mcg/mg, p=0.002). Conclusion: Our findings indicate that placenta from obese women develop insulin resistance similar to peripheral tissues, which can be overcome by high insulin doses. This placental insulin resistance likely occurs in response to chronic hyperinsulinemia, leading to interference of insulin signaling pathways, and may protect the neonate from excessive nutrient flux.

iPLEDGE Weaknesses: Is It Time to Address the Flaws?

BACKGROUND

The observance during acne follow-ups that information stored within iPLEDGE was discordant with medical charts prompted this study.

OBJECTIVE

To evaluate the information acquired and stored within iPLEDGE as it compares to medical charts with a goal of assessing the efficacy of iPLEDGE as a database.

METHODS

This is a multicenter retrospective chart review analyzing congruence and discrepancies between medical chart documentation and iPLEDGE data for all patients who received at least a single dose of isotretinoin from the primary investigators between January 2006 and November 2010.

RESULTS

A total of 357 charts were analyzed. Overall congruence between medical chart documentation and iPLEDGE data was observed in only 73.1% of cases. The discrepancy (N=96) was due to a missed dose (prescription recorded in chart but not in iPLEDGE) in 81.4% of cases, or an addition (medication dispensed per iPLEDGE without corresponding chart documentation) in the remainder of cases. Of note, several charts had multiple discrepancies (N=249 total discrepancies).

LIMITATIONS

Retrospective chart review study.

CONCLUSION

Given the large percentage of discordant data, our findings question the efficacy of the iPLEDGE system, which is designed to monitor every dispensed isotretinoin dose.