Plasma corticosteroid patterns in the fetus

Assessment of prenatal stress-related cortisol exposure: focus on cortisol accumulation in hair and nails

Prenatal stress adversely affects offspring development. Although cortisol is hypothesized to be a key mediator of stress-induced developmental deficits, determining the amount of fetal cortisol exposure produced by maternal stress has proved challenging. Current approaches, such as measuring cortisol concentrations in maternal plasma, saliva, or urine, amniotic fluid, fetal plasma, or cord blood, all have significant limitations for assessing cumulative fetal cortisol exposure over time. A recently emerging approach is to measure cortisol concentrations in maternal hair and/or newborn hair or nail samples. Maternal hair cortisol potentially shows long-term production across each trimester of pregnancy, whereas neonatal hair or nail cortisol is thought to reflect mainly third trimester hormone accumulation. This review first describes fetal adrenocortical development, placental cortisol metabolism, and the various sources of fetal cortisol exposure across pregnancy. We then summarize the results obtained from "classical" methods of assessing prenatal cortisol exposure prior to the advent of hair and nail cortisol measurement. Lastly, we discuss the initial development and validation of the hair cortisol methodology, its subsequent application to studies of chronic stress, and recent findings regarding maternal and neonatal hair or nail cortisol concentrations in relation to prenatal stress and other variables of interest.

CYP21A2 expression is localized in the developing distal epithelium of the human perinatal lung and is compatible with in situ production and intracrine actions of active glucocorticoids

Glucocorticoids play essential roles in lung development. We investigated for expression of CYP21A2 (21-hydroxylase) as well as for the presence of the corresponding protein and identification of CYP21A2-expressing cells in several human developing lungs. Expression of some related genes was also assessed. CYP21A2 and CYP17A1 (P450c17) mRNAs were found in all the 34 lung samples from 17 to 40 weeks' gestation at variable levels. No correlation was found according to sex but a correlation with age was detected for CYP17A1 only. In contrast, CYP11B1 (11β-hydroxylase)- and CYP11B2 (aldosterone synthase)-mRNAs were not detected. Significant levels of the CYP21A2 protein were detected in all the analyzed samples, while only very low signals were detected for CYP17A1 protein. In situ hybridization revealed that CYP21A2 was almost exclusively expressed in the distal epithelium. It was reported that the lung distal epithelium of human fetuses also express 11β-hydroxysteroid dehydrogenase type 2, which catalyzes cortisol inactivation into cortisone. Based on this information, intracrine glucocorticoid actions should take place from CYP21A2 products through the glucocorticoid receptor in the absence of cortisol. In contrast, mineralocorticoid receptor activation did not seem to depend on deoxycorticosterone produced from local activity of CYP21A2 because of the reported circulating amounts of aldosterone.

Cortisol production rates in preterm infants in relation to growth and illness: a noninvasive prospective study using gas chromatography-mass spectrometry

CONTEXT

Whereas intrauterine growth and maturation depend on low cortisol levels, an adrenal stress response postnatally is thought to be mandatory in preterm infants.

OBJECTIVE

The goal of this study was to determine cortisol production rates (CPRs) in preterm infants during early life with extreme illness and, thereafter, during extrauterine growth and maturation.

DESIGN

We describe a longitudinal observational study.

SETTING

The study was conducted at a university neonatal intensive care unit.

PATIENTS AND METHODS

Seventeen well (27.9 +/- 1.8 wk) and 44 ill (27.3 +/- 1.6 wk) preterm infants were classified by the Score for Neonatal Acute Physiology. Glucocorticoid metabolites were profiled by gas chromatography-mass spectrometry in 24-h urinary samples. Urine was collected noninvasively using cellulose nappies and extracted by hydraulic press.

RESULTS

Medians of CPRs (microg kg(-1) d(-1) mg creatinine) in ill (well) preterm infants were as follows: at d 1, 35 (40); d 2, 35 (40); d 3, 48 (53); d 5, 47 (41); wk 2, 72 (48); wk 3, 73 (37); wk 4, 54 (26). Regression analysis revealed a significant inverse influence of gestational age (P < 0.005) on the maximum of CPRs but not of severity of illness (Score for Neonatal Acute Physiology; P = 0.72). A mature adrenal response was found in only 12 of 44 (27%) ill preterm infants, who had CPRs higher than the 3-fold median of CPRs of well infants. This mature adrenal response was associated with a significantly higher incidence of cerebral bleeding: 9 of 12 (75%) vs. 8 of 32 (25%) without such a response (P = 0.003). During growth, CPRs of ill (well) preterm infants decreased: at month 2, 30 (18); month 3, 18 (22); correlation between weight gain and decrease of CPRs in ill infants between wk 4 and month 3, r = -0.48 (P = 0.027).

CONCLUSIONS

Severity of illness did not have a significant influence on CPRs in preterm infants. However, the highest CPRs were associated with a significantly higher incidence of cerebral bleeding. During growth, CPRs decreased significantly, suggesting that preterm infants have the ability to regulate cortisol production. CPRs in ill preterm infants might reflect inadequate stress reaction, but this could also reveal persistence of fetal protective mechanisms against high catabolic cortisol concentrations.

Assessing cortisol production in preterm infants: do not dispose of the nappies

The aim of this study was to develop a practical approach allowing a reliable and noninvasive assessment of cortisol production rates in premature infants. To measure daily urinary excretion rates of glucocorticoids, we developed a procedure using a hydraulic compression method to collect urine from cellulose nappies (diapers). Glucocorticoid metabolites were profiled by quantitative gas chromatography-mass spectrometry. Recovery of steroids after the process of hydraulic extraction from the nappy was approximately 100%. Consecutively, urinary excretion rates of glucocorticoids could be determined in nine healthy preterm infants. The median urinary excretion rate of glucocorticoids increased significantly during the first 5 d of life and remained between 566 microg/kg/d at d 5 and 302 microg/kg/d at 4 wk of age. However, this increase of urinary excretion rates of glucocorticoids in the first days of life was no longer significant when corrected for creatinine excretion. When calculated per square meter body surface area, the median urinary excretion rates of glucocorticoids were 5.1, 4.2, 4.1, and 3.7 mg/m2/d on d 5, and at wk, 2, 3, and 4, respectively. Urinary excretion rates of glucocorticoids constitute approximately 70% of the natural cortisol production rate as determined by stable isotope dilution technique in older children. Additionally, low cortisol production was detected in two of five preterm infants with arterial hypotension requiring treatment with catecholamines. In conclusion, 24-h urine collection using disposable nappies in combination with gas chromatography-mass spectrometry steroid profiling proved to be a reliable, noninvasive, nonstressful procedure to assess cortisol production and metabolism in premature infants.

Plasma cortisol, cortisone and urinary glucocorticoid metabolites in preterm infants

OBJECTIVE AND METHODS

In the fetal circulation, there is a low cortisol:cortisone (F:E) ratio ( approximately 0.3) suggesting high activity of 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2). The circulating F:E ratio rises after birth in term infants, but little is known about infants born prematurely. Our hypothesis was that the low fetal plasma F:E ratio would persist in infants born prematurely, due to persistently high tissue 11betaHSD2 activity. To test this hypothesis, a longitudinal observational study of plasma F, E levels and urinary F and E metabolites was performed in 22 preterm infants of 24-31 weeks gestation.

RESULTS

Median plasma F was 234-380 nmol l(-1), median 124-177 nmol l(-1) from 1 to 14 days age. Plasma F fell with increasing postnatal and postconceptional age. The F:E ratio was 3 in the first week of life, and thereafter was 1-2, falling with postnatal age. Urinary glucocorticoid metabolites were low in quantity ( approximately 48-120 microg kg(-1) day(-1)), consisted of E metabolites until term, and did not reflect the plasma F:E ratio.

CONCLUSIONS

The fetal plasma F:E ratio did not persist in these preterm infants, due to tenfold higher levels of F. The F:E ratios were similar to those reported in term infants. These data suggest that the low F:E ratio in utero is due to low fetal production of cortisol, and effective placental inactivation of maternal F by 11betaHSD2.

Evidence for change of 11beta-hydroxysteroid dehydrogenase activity during infancy and childhood

The conversion of cortisol (F) to cortisone (E) is catalyzed by 11beta-hydroxysteroid dehydrogenase type 2. The present study was designed to investigate the changes of F and E plasma concentration as an indirect measurement of 11beta-hydroxysteroid dehydrogenase activity in infancy and childhood. Plasma samples were obtained from 262 healthy children and adolescents aged 1 d to 18 y. Plasma F and E were measured, using specific radioimmunoassays after extraction and automated Sephadex LH 20 chromatography. The F/E ratio was calculated to assess 11beta-hydroxysteroid dehydrogenase activity. During the first year of life, plasma F levels rose significantly (r(2) = 0,24; p = 0.01), and thereafter no further increase was seen until adulthood (r(2) = 0.01; p = 0.86). In contrast, plasma E significantly decreased during the first year of life (r(2) = -0.35; p<0.001) and stayed unchanged thereafter (r(2) = 0.02; p = 0.81). As a consequence, the F/E ratio rose significantly during the first year (r(2) = 0.67; p<0.001) but did not change afterward (r(2) = 0.001; p = 0.99). During the first year of life, there is a change from the predominance of E, with low mineralocorticoid receptor affinity, to F, with high mineralocorticoid receptor affinity. This shift corresponds to the declining plasma concentrations of aldosterone during infancy. The changes may indicate a not yet recognized, significant change of 11beta-hydroxysteroid dehydrogenase isoenzyme activity or alterations in the secretion of F and E, which may be of relevance for the development of arterial blood pressure in infancy.

Adrenal function in preterm infants: ACTH may not be the sole regulator of the fetal zone

The fetal zone of the adrenal gland is known to persist after preterm birth, but there is uncertainty as to how long adrenal fetal zone steroid production continues and how it is regulated. The purpose of this study was to test two hypotheses. First, that the urinary excretion of 3beta-OH-5-ene steroids persists until term, and then declines, as it does in full-term infants. Second, that the persistence of the fetal zone is due to continuing ACTH stimulation. A longitudinal observational study was undertaken in 22 preterm infants of 24-31-wk gestation. Sequential measurements were made of urinary 3beta-OH-5-ene steroids (fetal zone steroid metabolites), plasma dehydroepiandrosterone sulfate (DHEAS), and ACTH. Excretion of urinary 3beta-OH-5-ene steroids was 1500-2000 microg kg(-1) d(-1), persisting until term, and declining abruptly at approximately 42 wk postconceptional age (PCA), to levels comparable to term infants at the same PCA. Median plasma ACTH levels rose from <7.6 pg mL(-1) at 25-wk PCA to 34.5 pg mL(-1) at 46-wk PCA. Urinary 3beta-OH-5-ene steroids were highest when ACTH levels were lowest, and were declining when ACTH was rising. In four infants given dexamethasone, urinary excretion of 3beta-OH-5-ene steroids and plasma DHEAS were not suppressed fully, when plasma ACTH and cortisol, and urinary cortisol metabolites were. These data suggest that ACTH is not the sole regulator of the adrenal fetal zone steroid synthesis and that involution of the fetal zone is related to gestation rather than birth.

Radioimmunoassay of cortisone in serum, urine, and saliva to assess the status of the cortisol–cortisone shuttle

We have developed a new assay for cortisone (E) in serum, saliva, and urine involving Celite® chromatography followed by RIA with 125I-labeled E and scintillation proximity assay. The chromatography step separates cortisol (F) from E, and in combination with their RIAs, permits assessment of the status of the F–E shuttle. We report the results of basal, postcorticotropin (ACTH), and postdexamethasone E and F concentrations and their circadian fluctuations in the serum, saliva, and urine of healthy volunteers. The serum and urine F/E ratios were increased in patients with ectopic ACTH secretion, whereas in adrenal adenoma and Cushing disease only the urinary ratio was increased. In chronic renal insufficiency this ratio was increased in serum (23.5 ± 3.9) but diminished in saliva (0.38 ± 0.11), and in apparent mineralocorticoid excess the ratios were high in serum (44.3 ± 9.3) and urine (5.35 ± 0.85) compared with those of healthy subjects (serum 9.8 ± 3.5, urine 0.52 ± 0.29, saliva 0.52 ± 0.29).

High-performance liquid chromatographic analysis of corticosteroids

This review presents recent developments in high-performance liquid chromatographic (HPLC) analysis of corticosteroids for the determination of clinically important steroids in biological specimens. Various sample preparation techniques are described.

Determination of urinary cortisol with three commercial immunoassays

Urinary cortisol determination was performed with three commercially available immunoassays: one enzyme-immunoassay (Cortisol Biotrol) (EIA) and two radioimmunoassays: Quanticoat Cortisol (Kallestad Diagnostics) (KD-RIA) and GammaCoat Cortisol (Clinical Assays) (CA-RIA). Four procedures were carried out. Procedure I (methylene chloride extraction) was applied to EIA and CA-RIA and procedure II (ethyl acetate extraction) to KD-RIA. Procedure III combining procedure I and column chromatography on Sephadex LH 20 in methylene chloride was applied to the three kits. Procedure IV consisting of carbon tetrachloride preextraction and extraction with cyclohexane-ethyl acetate (50:50, v/v) was applied to CA-RIA. The results obtained were compared with those of the reference technique, "on-line" HPLC with u.v. detection. Two groups of results were arbitrarily considered, those below (n = 28) and those above (n = 6) 270 nmol/l. In the first group, the results were markedly overestimated when the procedure was limited to solvent extraction. Conversely, the third procedure proved the efficiency of the chromatographic step since specificity was greatly improved in the three cases, the levels obtained with either kits being similar to those of the reference technique. The second group of results (above 270 nmol/l) yielded by the three kits were not always higher than those of HPLC when the procedure was limited to solvent extraction. When column chromatography was included in the procedure, the results were comparable to those of HPLC in three cases and lower in the three others. Since, the latter samples were collected after cortisol administration, and overestimated cortisol values obtained by HPLC might be due to the interference of some cortisol metabolites.

Plasma C-21 steroids in conscious pregnant and non-pregnant rabbits with chronic catheterization of the femoral artery and the portal and hepatic veins

In conscious non-pregnant (n = 8) and pregnant (n = 7) rabbits, blood samples were collected by chronic catheterization of the femoral artery and the hepatic and portal veins. In the non-pregnant group, deoxycorticosterone (DOC), corticosterone (B), cortisone (E) and cortisol (F) were determined by RIA. In the pregnant group, progesterone (P) and 20 alpha-dihydroprogesterone were also radioimmunoassayed. The arterio-venous difference of the levels observed has demonstrated the role of the liver and the splanchnic area in steroid metabolism. Moreover, the comparison of the steroid pattern in the two groups showed that gravidity was characterized by a marked increase of F and E but not of B and DOC levels. Thus, the ratio of F/B in the femoral artery was markedly increased in the pregnant animals; this ratio ranged from 0.20 to 1.12 in the non-pregnant group, and from 1.3 to 12.5 in the pregnant group.

Percutaneous umbilical blood sampling

Percutaneous umbilical blood sampling (PUBS), also called cordocentesis, is a newly introduced technique that enables blood samples to be obtained from the fetus in utero for a variety of conditions. The major applications are for the diagnosis of fetal infections, karyotype analysis, fetal growth retardation, diagnosis of hematologic conditions, and metabolic evaluation. This procedure is gaining in popularity, since it provides direct information on fetal blood status. It can be applied to therapeutic manipulations such as in utero transfusions or drug administration. The procedure is remarkably safe and has few technical problems. The applicability of its use in the assessment of fetal thrombocytopenia is also discussed in detail.

Radioimmunoassay of plasma 21-deoxycortisol

A reliable radioimmunoassay for the determination of plasma 21-deoxycortisol (21-DF) after chromatography on Sephadex LH20 columns of methylene chloride plasma extracts has been described and evaluated. The antiserum used was raised in rabbits injected with 21-DF-3-(O-carboxy-methyl)oxime-bovine serum albumin. In men (n = 10) the levels ranged from 0.11 to 0.29 ng/ml (mean +/- SD: 0.21 +/- 0.06). In women the mean levels were in the follicular phase: 0.16 +/- 0.06 (range: 0.05-0.22; n = 10) and in the luteal phase: 0.18 +/- 0.06 (range: 0.10-0.35; n = 12). No cyclical change and no significant difference between male and female groups were observed. In patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency very high levels were observed. The higher concentration of 21-DF found in adrenal effluent than in peripheral plasma has provided direct evidence of its adrenal origin in patients without 21-hydroxylase deficiency.

Corticosteroid sulfates in fetus plasma

The sulfates of deoxycorticosterone (DOCS), corticosterone (BS), cortisone (ES) and cortisol (FS) were radioimmunoassayed in umbilical vein blood plasma samples collected in 97 fetuses between 19 and 32 weeks of gestation after extraction and chromatography on Sephadex LH 20 columns. While DOCS and BS displayed a decreasing pattern until 27-28 weeks, FS and ES did not show important variations throughout the period considered. All sulfates, excepted BS, increased at 29-30 weeks but this rise was only significant for FS and ES. Thereafter BS significantly increased while no significant difference could be displayed for the three others. In view of the difference between the patterns of 17-deoxy- and 17-hydroxycorticosteroids, one can speculate that, during this period of pregnancy, a shift in steroid biogenesis might occur towards a more important production of cortisol. DOCS was correlated with BS and with FS but not with ES. FS was correlated with the three other sulfates and with unconjugated F. ES was correlated with BS and FS but not with DOCS or unconjugated E. The significance of these correlations are discussed according to the origin and the metabolic interrelationships of the four steroid sulfates and unconjugated F and E.