Effect of lactation on ectopic lipid after gestational diabetes
This is a single site study to examine iMCL in soleus muscle of the leg and intra-hepatic triglyceride (iHTG) during postpartum physiology in 4 groups of women. Two groups have physiologic hyperprolactinemia of lactation (healthy lactating group and lactating GDM group). The other 2 groups are not lactating and have normal pre-pregnancy prolactin levels (healthy non-lactating group and non-lactating GDM group).
Lactating and non-lactating postpartum women who are 2 to 5 weeks from full-term delivery will be invited to participate in study procedures (1) at 5 to 7 weeks postpartum only (3 study visits) or (2) at both 5 to 7 weeks postpartum and at 15 to 17 weeks postpartum (6 study visits). on Visit 1 those women interested in participating in this project will go through the informed consent process, screening for inclusion and exclusion criteria, a complete history and physical exam, a 2-hour oral glucose tolerance test (2-hour oGTT), measurement of total and regional body fat by dual energy X-Ray absorptiometry (DeXa), nutritional assessment, physical activity assessment, and screening for postpartum depression. Visit 4 resembles Visit 1 with the exception that a 2-hour oGTT will not be performed. on Visit 2, participants will have a 2-step hyperinsulinemic euglycemic clamp for determination of whole-body insulin resistance, indirect calorimetry to assess resting energy expenditure and fasting nutrient utilization, a follow-up nutritional assessment, and a follow-up physical activity assessment. Stable isotopes will be administered by oral and iV routes. Visit 5 is identical to Visit 2. on Visit 3, participants will have proton magnetic resonance spectroscopy (1H-MRS) of the soleus muscle in the leg using a 7-Tesla magnet, 1H-MRS of the liver using a 3-Tesla magnet, and a biopsy of the subcutaneous adipose tissue of the buttock. Visit 6 is identical to Visit 3.
Study participants will be screened for postpartum depression during Visit 1 and Visit 4. Participants will be allocated to the lactating and non-lactating arms based on their postpartum choice to feed their newborns with breast milk only or no breast milk, respectively. This study examines postpartum physiology in non-diabetic women after delivery with no need of a treatment intervention. The primary outcome variable is the between group mean difference in the mean longitudinal change in iMCL content in the soleus muscle between lactating and non-lactating women with GDM. The secondary outcomes are:
Cross-sectional and longitudinal change in (a) iHTG content , (b) whole-body insulin resistance, (c) fasting high molecular weight adiponectin, prolactin, insulin, free fatty acids, leptin, resistin, and RBP4 (retinol binding protein 4) concentrations in blood, (d) lipolysis, (e) production of glucose by the liver, (f) new lipid synthesis, and (g) adipocyte cell size/function between lactating and non-lactating postpartum women. The maximum number of subjects to be consented on this protocol is 120. The researchers expect to complete the study with 36 subjects. at the end of the study the post-GDM groups will have an equal sample size of 12 per group and the healthy postpartum groups will have an equal sample size of 6 per group. Potential participants in excess of the numbers described above will be disqualified even if they meet the inclusion criteria.
The duration of participation in this research will be 12-15 weeks in the longitudinal design. Subjects will be compensated with a $75 gift card for Visit 1, a $225 check for completion of Visit 2, a $300 check for completion of Visit 3, a $75 gift card for Visit 4, a $225 check for completion of Visit 5, and a $300 check for completion of Visit 6. This compensation includes child care expenses. a voucher for a meal will be provided at each visit and parking expenses will be covered when parking at the Clements imaging Building.
This protocol is specific for women in the postpartum period after a normal pregnancy or a pregnancy with gestational diabetes. The inclusion criteria are:
1- Healthy pregnancy or pregnancy complicated by GDM according to the National Diabetes Data Group
2- For participants with history of GDM, only those treated with diet (without insulin) during pregnancy will be included
3- Postpartum period (<=7 weeks postpartum at Visit 1)
4- Term pregnancy of 1 newborn
5- Age 21-49
6- BMI at 2 weeks postpartum 25-35 kg/m2
7- Personal choice to exclusively breastfeed for >=16 weeks or no breastfeeding
8- Intention to participate in the first set of 3 study visits between 5 and 7 weeks postpartum (within 10 to 14 days) and the second set of 3 study visits within 15 and 17 weeks postpartum (also within 10 to 14 days)
9- Hispanic or non-Hispanic white ethnicity/race because this is a small study and variability of the main outcome variables by ethnicity/race has been documented
10- English and/or Spanish-speaking subjects