A longitudinal study of circulating progesterone, oestradiol, hCG and hPL during pregnancy in type 1 diabetic mothers

Multi-omics reveal disturbance of glucose homeostasis in pregnant rats exposed to short-chain perfluorobutanesulfonic acid

Perfluorobutanesulfonic acid (PFBS), a short-chain alternative to perfluorooctanesulfonic acid (PFOS), is widely used in various products and is increasingly present in environmental media and human bodies. Recent epidemiological findings have raised concerns about its potential adverse health effects, although the specific toxic mechanism remains unclear. This study aimed to investigate the metabolic toxicity of gestational PFBS exposure in maternal rats. Pregnant Sprague Dawley (SD) rats were randomly assigned to three groups and administered either 3% starch gel (control), 5, or 50 mg/kg bw·d PFBS. Oral glucose tolerance tests (OGTT) and lipid profiles were measured, and integrated omics analysis (transcriptomics and non-targeted metabolomics) was employed to identify changes in genes and metabolites and their relationships with metabolic phenotypes. The results revealed that rats exposed to 50 mg/kg bw·d PFBS exhibited a significant decrease in 1-h glucose levels and the area under the curve (AUC) of OGTT compared with the starch group. Transcriptomics analysis indicated significant alterations in gene expression related to cytochrome P450 exogenous metabolism, glutathione metabolism, bile acid secretion, tumor pathways, and retinol metabolism. Differentially expressed metabolites (DEMs) were enriched in pathways such as pyruvate metabolism, the glucagon signaling pathway, central carbon metabolism in cancer, and the citric acid cycle. Co-enrichment analysis and pairwise correlation analysis among genes, metabolites, and outcomes identified several differentially expressed genes (DEGs), including Gstm1, Kit, Adcy1, Gck, Ppp1r3c, Ppp1r3d, and DEMs such as fumaric acid, L-lactic acid, 4-hydroxynonenal, and acetylvalerenolic acid. These DEGs and DEMs may play a role in the modulation of glucolipid metabolic pathways. In conclusion, our results suggest that gestational exposure to PFBS may induce molecular perturbations in glucose homeostasis. These findings provide insights into the potential mechanisms contributing to the heightened risk of abnormal glucose tolerance associated with PFBS exposure.

Human Placental Lactogen in Relation to Maternal Metabolic Health and Fetal Outcomes: A Systematic Review and Meta-Analysis

Human placental lactogen (hPL) is a placental hormone which appears to have key metabolic functions in pregnancy. Preclinical studies have putatively linked hPL to maternal and fetal outcomes, yet-despite human observational data spanning several decades-evidence on the role and importance of this hormone remains disparate and conflicting. We aimed to explore (via systematic review and meta-analysis) the relationship between hPL levels, maternal pre-existing and gestational metabolic conditions, and fetal growth. MEDLINE via OVID, CINAHL plus, and Embase were searched from inception through 9 May 2022. Eligible studies included women who were pregnant or up to 12 months post-partum, and reported at least one endogenous maternal serum hPL level during pregnancy in relation to pre-specified metabolic outcomes. Two independent reviewers extracted data. Meta-analysis was conducted where possible; for other outcomes narrative synthesis was performed. 35 studies met eligibility criteria. No relationship was noted between hPL and gestational diabetes status. In type 1 diabetes mellitus, hPL levels appeared lower in early pregnancy (possibly reflecting delayed placental development) and higher in late pregnancy (possibly reflecting increased placental mass). Limited data were found in other pre-existing metabolic conditions. Levels of hPL appear to be positively related to placental mass and infant birthweight in pregnancies affected by maternal diabetes. The relationship between hPL, a purported pregnancy metabolic hormone, and maternal metabolism in human pregnancy is complex and remains unclear. This antenatal biomarker may offer value, but future studies in well-defined contemporary populations are required.

Possible mechanisms involved in improved beta cell function in pregnant women with type 1 diabetes

Pregnancy is known to be associated with an increased demand for insulin that is normally compensated by an increased beta cell mass and insulin secretion. Recent studies have suggested enhanced beta cell function during pregnancy in women with type 1 diabetes (T1D). To explore the possible mechanisms behind enhanced beta cell function during pregnancy in women with T1D we investigated the impact of circulating factors in serum from nine women from each group of pregnant women with and without T1D, after pregnancy and non-diabetic non-pregnant women on rat islet cell proliferation and apoptosis, and on T-lymphocyte activation. In addition, circulating levels of pancreatic hormones and selected cytokines and adipokines were measured. Rat islet cell proliferation was higher in serum from pregnant women with T1D (p < 0.05) compared to T1D women after pregnancy. Apoptosis in INS-1E cell was lower (p < 0.05) in serum from pregnant women with T1D compared to T1D women after pregnancy. T-lymphocyte cell (Jurkat) proliferation was reduced by serum from pregnant women without T1D only (p < 0.05). Higher C-peptide levels and lower levels of ghrelin, IL-6, MCP-1, IL-8 and adipsin were observed in pregnant women with T1D compared to T1D women after pregnancy. In conclusion, the improved beta cell function in women with T1D during pregnancy may be due to lower levels of proinflammatory cytokines and/or higher levels of pregnancy-associated growth factors.

The Association of Falling Insulin Requirements With Maternal Biomarkers and Placental Dysfunction: A Prospective Study of Women With Preexisting Diabetes in Pregnancy

OBJECTIVE

To investigate the association of falling insulin requirements (FIR) among women with preexisting diabetes with adverse obstetric outcomes and maternal biomarkers longitudinally in pregnancy.

RESEARCH DESIGN AND METHODS

A multicenter prospective cohort study of 158 women (41 with type 1 diabetes and 117 with type 2 diabetes) was conducted. Women with FIR of ≥15% from the peak total daily dose after 20 weeks' gestation were considered case subjects (n = 32). The primary outcome was a composite of clinical markers of placental dysfunction (preeclampsia, small for gestational age [≤5th centile], stillbirth, premature delivery [<30 weeks], and placental abruption). Maternal circulating angiogenic markers (placental growth factor [PlGF] and soluble fms-like tyrosine kinase 1 [sFlt-1]), placental hormones (human placental lactogen, progesterone, and tumor necrosis factor-α), HbA_1c, and creatinine were studied serially during pregnancy.

RESULTS

FIR ≥15% were associated with an increased risk of the composite primary outcome (odds ratio [OR] 4.38 [95% CI 1.9-10.3]; P < 0.001), preeclampsia (OR 6.76 [95% CI 2.7-16.7]; P < 0.001), and was more common among women with type 1 diabetes (36.6 vs. 14.5%; P = 0.002). Creatinine was modestly elevated among women with FIR ≥15%; however, there was no difference in HbA_1c. The ratio of sFlt-1 to PlGF was significantly higher among women with FIR at 25, 30, and 36 weeks, with differences maintained in the subgroup that developed preeclampsia. There was no difference in placental hormones between the groups.

CONCLUSIONS

This is the first prospective study to associate FIR with altered expression of placental antiangiogenic factors and preeclampsia. FIR are an important clinical sign, among women with preexisting diabetes, that should alert the clinician to investigate underlying placental dysfunction.

Effect of pregnancy on insulin requirements differs between type 1 and type 2 diabetes: A cohort study of 222 pregnancies

BACKGROUND

Knowledge about expected insulin requirements during pregnancy, in women with pre-existing diabetes may assist clinicians to effectively respond to gestation-specific changes in glycemic pattern. Few studies have examined differences between type 1 (T1DM) and type 2 diabetes (T2DM).

AIMS

To compare patterns of insulin requirements in pregnancy for women with pre-existing T1DM and T2DM.

MATERIAL AND METHODS

A retrospective cohort study of 222 pregnancies was conducted in women with pre-existing diabetes, (67 with T1DM, 155 with T2DM). Total daily insulin dose (TID) at the end of each trimester, recorded as units and units per kilogram (median, 25th-75th percentile) as well as percentage increase in insulin dose per trimester were compared.

RESULTS

Women with T1DM had higher insulin requirements in the first two trimesters than those with T2DM (0.69 (0.58-0.85) vs 0.36 (0.0-0.7) units/kg in first trimester; 0.80 (0.62-0.95) vs 0.61 (0.27-0.95) units/kg, P < 0.005) in second trimester), but requirements in late pregnancy were similar (0.97 (0.69-1.29) vs 0.95 (0.53-1.32) units/kg, P = 0.54). Women with T2DM needed much greater increases in insulin per trimester compared to T1DM (P < 0.001). Women with T1DM had a net fall in insulin requirements (3.7% in the first trimester and 4.1% in the late third trimester) while those with T2DM did not.

CONCLUSIONS

This is the largest comparison study of insulin requirements in women with pre-existing diabetes, highlighting important trimester-specific differences between T1DM and T2DM to guide insulin titration during pregnancy. Our findings suggest a differential effect of pregnancy-mediated insulin resistance by type of diabetes.

Gestational and hormonal regulation of human placental lipoprotein lipase

The fetal demand for FFA increases as gestation proceeds, and LPL represents one potential mechanism for increasing placental lipid transport. We examined LPL activity and protein expression in first trimester and term human placenta. The LPL activity was 3-fold higher in term (n = 7; P < 0.05) compared with first trimester (n = 6) placentas. The LPL expression appeared lower in microvillous membrane from first trimester (n = 2) compared with term (n = 2) placentas. We incubated isolated placental villous fragments with a variety of effectors [GW 1929, estradiol, insulin, cortisol, epinephrine, insulin-like growth factor-1 (IGF-1), and tumor necrosis factor-alpha] for 1, 3, and 24 h to investigate potential regulatory mechanisms. Decreased LPL activity was observed after 24 h of incubation with estradiol (1 micro g/ml), insulin, cortisol, and IGF-1 (n = 12; P < 0.05). We observed an increase in LPL activity after 3 h of incubation with estradiol (20 ng/ml) or hyperglycemic medium plus insulin (n = 7; P < 0.05). To conclude, we suggest that the gestational increase in placental LPL activity represents an important mechanism to enhance placental FFA transport in late pregnancy. Hormonal regulation of placental LPL activity by insulin, cortisol, IGF-1, and estradiol may be involved in gestational changes and in alterations in LPL activity in pregnancies complicated by altered fetal growth.

Abnormal relaxin secretion during pregnancy in women with type 1 diabetes

To test the hypothesis that relaxin may play a role in the fetal abnormalities associated with pregnancy in type 1 diabetic women, we previously compared gestational relaxin concentrations in diabetic and clinically normal women using a porcine relaxin radioimmunoassay (RIA): Serum immunoactive relaxin was significantly (P < 0.001) elevated in the diabetic women. To confirm and extend this work in a larger group of subjects, we have now used an enzyme-linked immunosorbent assay (ELISA) specific for human H2 relaxin (the normal human gene product) to determine immunoactive serum relaxin concentrations in serial samples from 61 Type 1 diabetic and 21 normal pregnant women. Samples from 22 of the diabetic and nine of the normal women were also directly compared in the porcine relaxin RIA. ELISA-determined serum relaxin was higher (P < 0.001) at 24 and 36 weeks of pregnancy in type 1 diabetic women than in controls, confirming previous findings. However, the geometric mean increase in immunoactive relaxin concentration in identical samples from pregnant diabetic women over that of controls was significantly greater with the RIA than with the ELISA (271% vs 44%; P < 0.001). To investigate this discrepancy, the specificity and epitope selectivity of the RIA and the ELISA were compared using several synthetic polypeptides, including human relaxins H1 and H2, and relaxin and insulin derivatives. Both assays showed great specificity, but the porcine RIA selectively identified the epitopes of the receptor-binding domain of the relaxin B chain and cross-reacted strongly with H1 and H2 relaxins. In contrast, only the H2 peptide was detected by the ELISA antiserum. Therefore, the marked discrepancy between the RIA and the ELISA could be due to the presence in the diabetic samples of another relaxin-like molecule in addition to the normal H2 relaxin. The biological consequences of elevated serum relaxin in diabetic pregnancy remain to be elucidated.

Lactogenesis and the effects of insulin-dependent diabetes mellitus and prematurity

The initiation of lactation (lactogenesis II) by the mother must be synchronized to the delivery of the infant, permitting the transition of the newborn from continuous nourishment from the umbilical cord to comparable but intermittent life support from its mother's breasts. The onset of lactogenesis II can be adversely affected by a variety of factors. Over 80% of women who have delivered prematurely and are expressing milk for their infant had a compromised initiation of lactation, that is one or more lactogenesis II markers (lactose, citrate, sodium and total protein) in their milk > 3 SD from the mean of the full-term women on d 5 postpartum. Similarly, the lactogenesis II markers (lactose, citrate and total nitrogen) in the milk of women with insulin-dependent diabetes mellitus take an additional 24 h to attain the concentrations of normal women. The mechanisms that lead to the development of delayed or compromised onset of lactogenesis II in women are poorly understood and require additional research.

Detection of placental growth hormone variant and chorionic somatomammotropin-L RNA expression in normal and diabetic pregnancy by reverse transcriptase-polymerase chain reaction

Diabetes is a common complication encountered during pregnancy. Earlier studies indicated that diabetic placentas bear morphological alterations consistent with modified placental differentiation, including alterations in the villous cellular content, structure, and total surface. Limited data associating the diabetic status with the expression of terminal placental differentiation markers are available. The human growth hormone/chorionic somatomammotropin (hGH/CS) family consists of five genes, one of which (GH-N) is expressed efficiently in pituitary while the other four (CS-A, B, L, and hGH-V) are expressed in placenta and represent ultimate placental differentiation markers. We developed and applied a sensitive RT-PCR method coupled with diagnostic restriction digestion to determine the relative levels of the hGH/CS family in normal pregnancies and examine whether their mRNA expression pattern is altered in pregnancies complicated by diabetes. We show that relative hCS-L content changes during placental development. Specifically, normal term placentas express higher relative levels of hCS-L, lower relative hGH-V levels and a 70-fold lower hGH-V/CS-L mRNA ratio compared to early placentas. Also, many term placentas from diabetic pregnancies express lower relative levels of hCS-L mRNA and a much higher hGH-V/CS-L mRNA ratio compared to normal term placenta, resembling more an early placenta pattern of expression. Thus, our study suggests that the expression of terminal placental differentiation markers, such as the hGH/CS genes, is altered in term placentas from these diabetics reflecting either impaired placental differentiation or post-differentiation impairment of normal placental function.

The intravascular mass of albumin during human pregnancy: a serial study in normal and diabetic women

OBJECTIVE

To quantify the changes in serum albumin during human pregnancy.

DESIGN

Longitudinal prospective study.

SETTING

Before conception and antenatal clinic.

SUBJECTS

Sixty-nine normal women and 23 women with Type 1 diabetes.

INTERVENTIONS

Administration of Evans' blue dye and collection of serum samples.

MAIN OUTCOME MEASURES

Albumin concentration, plasma volume and intravascular mass of albumin.

RESULTS

In normal subjects serum albumin concentration showed a significant decrease of 1.9 (95% CI 1.0 to 2.9) g/l by 7 weeks gestation with a further 8.2 (95% CI 7.5 to 8.9) g/l decrease by 36 weeks gestation, an overall change of 22%. Plasma volume first increased significantly by 190 (95% CI 105 to 275) ml between 7 and 12 weeks, with a further increase of 1003 (95% CI 871 to 1135) ml between 12 and 36 weeks of pregnancy, a change of 53%. The intravascular mass of albumin showed no change between non-pregnant, 7 and 12 week values but there was a significant rise of 19.5 (95% CI 15.1 to 23.9) g between 12 and 28 weeks of gestation, an overall increase of 19%. Diabetic subjects showed similar changes.

CONCLUSIONS

Rather than simply reflecting plasma volume dilution, the changes in serum albumin imply alterations in albumin metabolism during pregnancy.

An association between elevated levels of human chorionic gonadotropin in the midtrimester and adverse pregnancy outcome

OBJECTIVE

Unexplained elevations in maternal serum alpha-fetoprotein in the midtrimester are associated with adverse pregnancy outcome. Recently it has also been suggested that elevations of maternal serum human chorionic gonadotropin in the second trimester may be associated with adverse pregnancy outcome.

STUDY DESIGN

We conducted a cohort study of 460 women at Swedish Medical Center, Seattle, Washington, between Jan. 1, 1990, and Aug. 15, 1991, inclusive. Entry criteria for the cohort included (1) triple screen analysis (maternal serum alpha-fetoprotein, human chorionic gonadotropin, unconjugated estriol) between 15 and 18 weeks' gestation, (2) a risk for Down syndrome of more than one in 195 on the basis of triple screen analysis, (3) study group human chorionic gonadotropin > or = 2 multiples of the median and referent group < or = 2 multiples of the median, alpha-fetoprotein < or = 2 multiples of the median, unconjugated estriol > or = 0.5 multiples of the median, and (4) chromosomally normal single gestation without anomalies. Cumulative incidence risk ratios were estimated for each pregnancy outcome as a measure of the relative association with elevated human chorionic gonadotropin (> or = 2.0 multiples of the median) and adverse pregnancy outcome: low birth weight, < or = 2500 gm; preterm delivery, < 37 weeks' gestation; and small for gestational age, < or = 10th percentile. The Mantel extension test was used to evaluate any apparent linear trend in risk between level of human chorionic gonadotropin and adverse pregnancy outcome.

RESULTS

Elevated human chorionic gonadotropin levels were associated with an increased risk for low birth weight (relative risk = 4.0), preterm delivery (relative risk = 2.8), and small for gestational age (relative risk = 1.8). The risk for each adverse outcome increased with increasing levels of human chorionic gonadotropin.

CONCLUSIONS

Elevations of human chorionic gonadotropin in the midtrimester appear to be associated with adverse pregnancy outcome. The magnitude of the risk correlates with the level of human chorionic gonadotropin. This risk appears to be independent of the risk for adverse pregnancy outcome associated with unexplained elevations of maternal serum alpha-fetoprotein.

Maternal relaxin concentrations in diabetic pregnancy

Maternal serum concentrations of relaxin, an insulin homologue produced both by the corpus luteum of pregnancy and by the fetoplacental unit, are highest in the first trimester and fall to their lowest level in the third trimester. Relaxin is thought to influence carbohydrate metabolism in the uterus, and it has been suggested that serum concentrations of relaxin in diabetic women are higher than those of non-diabetic women. We show that maternal serum relaxin concentrations are significantly higher at each stage of pregnancy in insulin-dependent diabetic mothers than in non-diabetic mothers. This elevation in relaxin concentrations is not related to other indices of diabetic control. The physiological importance of the higher concentrations of relaxin in the serum of diabetic women--in particular, whether they contribute to the higher incidence of major anomalies in the fetuses of diabetic mothers--is yet to be determined.

Maternal serum unconjugated oestriol and human chorionic gonadotrophin levels in pregnancies with insulin-dependent diabetes: implications for screening for Down's syndrome

OBJECTIVE

To investigate maternal serum unconjugated oestriol (uE3) and human chorionic gonadotrophin (hCG) levels in pregnant women with insulin-dependent diabetes mellitus and to consider the implications of the results for antenatal screening for Down's syndrome.

DESIGN

Descriptive study using stored antenatal serum samples.

SETTING

Stored serum samples collected from women receiving routine antenatal care in Oxford.

SUBJECTS

126 singleton pregnancies in 92 women with insulin-dependent diabetes mellitus and for each pregnancy, two pregnancies without diabetes matched for gestational age and duration of storage of the serum sample. None of the pregnancies was associated with fetal neural tube defect or Down's syndrome.

MAIN STUDY MEASURES

Maternal serum uE3 and hCG levels at 15-22 weeks gestation. Alpha-fetoprotein (AFP) levels were also measured for comparison.

RESULTS

The median uE3 level in the diabetic pregnancies was 0.92 multiples of the median (MoM) for pregnancies without diabetes at the same gestational age (P less than 0.05); and the hCG level was 0.95 MoM (P = 0.48). The median AFP level was also reduced to 0.77 MoM (P less than 0.001).

CONCLUSION

The reduction in uE3 and AFP levels in insulin-dependent diabetic pregnancies is sufficiently great to be taken into account in maternal serum screening programmes for Down's syndrome. Dividing the uE3 and AFP levels in such pregnancies by the corresponding median for insulin-dependent diabetic pregnancies will yield a similar false-positive rate in pregnancies with and without insulin-dependent diabetes mellitus.