Salivary alpha-amylase as a non-invasive biomarker for the sympathetic nervous system: current state of research.

The Uterine Spiral Arteries In Human Pregnancy: Facts and Controversies

Context.—The value of placental examination in investigations of adverse pregnancy outcomes may be compromised by sampling and definition differences between laboratories. Objective.—To establish an agreed-upon protocol for sampling the placenta, and for diagnostic criteria for placental lesions. Recommendations would cover reporting placentas in tertiary centers as well as in community hospitals and district general hospitals, and are also relevant to the scientific research community. Data Sources.—Areas of controversy or uncertainty were explored prior to a 1-day meeting where placental and perinatal pathologists, and maternal-fetal medicine specialists discussed available evidence and subsequently reached consensus where possible. Conclusions.—The group agreed on sets of uniform sampling criteria, placental gross descriptors, pathologic terminologies, and diagnostic criteria. The terminology and microscopic descriptions for maternal vascular malperfusion, fetal vascular malperfusion, delayed villous m...

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Sampling and Definitions of Placental Lesions: Amsterdam Placental Workshop Group Consensus Statement

Determinants of the diurnal course of salivary alpha-amylase

The evolutionary adaptation in mammals that allows implantation of their embryos in the mother's womb creates an immunological problem. Although it ensures optimal nourishment and protection of the fetus throughout its early development, intimate contact with the mother's uterine tissue makes the fetus a potential target for her immune system. As half the fetal genes are derived from the father, the developing embryo and placenta must be considered a 'semi-allograft'. Such a mismatched organ transplant would be readily rejected without powerful immune suppression. During pregnancy, however, the semi-allogeneic fetus is protected from assault by the maternal immune system over an extended period of time. The mother's immune system seems to recognize the fetus as 'temporary self'. How this feat is managed is key to understanding immunological tolerance and intervention in treating disease.

Mother's little helpers: mechanisms of maternal-fetal tolerance

The objective of this cross-sectional study was to construct new reference ranges for Doppler flow velocity waveform resistance indices for the fetal umbilical artery, middle cerebral artery, placental and non-placental uterine arteries and the placentocerebral ratio in a large and minimally selected population attending a single clinic. Study design and data analysis adhered to a number of stringent and validated methodological recommendations derived both from the recent literature and from a review of earlier publications in this field. The final database comprised initial routine Doppler velocimetry at 24-42 weeks' gestation in 1675 pregnancies. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each vessel. New charts, centile tables and regression equations are presented for the resistance indices of the fetal umbilical artery, middle cerebral artery, placental and non-placental uterine arteries and the mean of both uterine arteries and for the placentocerebral ratio.

Reference resistance indices of the umbilical, fetal middle cerebral and uterine arteries at 24–42 weeks of gestation

Context: We and others have previously shown that standardized psychosocial stress significantly increases salivary α-amylase (sAA), but it remains unclear whether sAA reflects autonomic nervous system activation. Objective: The aim of this study was to assess cardiovascular effects and sAA and catecholamine secretion after iv injection of yohimbine. Design and Setting: We conducted a randomized double-blind placebo-controlled study at an academic research unit. Participants: Thirteen healthy males (aged 20–28 yr) were examined. Intervention: Participants received iv injection of yohimbine (0.4 μg/kg) or placebo (0.9% NaCl). Main Outcome Measures: Eight saliva and blood samples were taken before and after injection for the assessment of salivary flow rate and sAA and catecholamine concentrations. In addition, blood pressure, mood, and anxiety were assessed repeatedly. Results: Yohimbine induced increases of sAA activity and output in comparison to placebo (P = 0.034). Blood pressure (P < 0.001), salivary ...

Salivary α-amylase levels after yohimbine challenge in healthy men

Rescue by birth: defective placental maturation and late fetal mortality.

Pregnancy represents the growth of an allograft where fetal trophoblast cells evade immune rejection and invade maternal tissue. There should be a balance between fetal trophoblast and maternal immune-responsive cells and alterations in the proportion of these cells may relate to pregnancy disorders. To test this, the decidual tissue of placental bed biopsies was examined and trophoblast cells and lymphocytes were quantified morphometrically; spiral arteries were classified as unchanged, transformed or affected by acute atherosis. Normal pregnancy (n=19) was characterized by the transformation of about one half of all spiral arteries within the placental bed. We found that 40% of all lymphocytes were CD56+ uterine NK cells and 60%, CD3+ T-lymphocytes; about 30% of these were CD8+ T cells. Intrauterine growth retardation in the context of preeclampsia (n=15) was accompanied by reduced trophoblast numbers within smaller and more tortuous arteries and an increase in the proportion of CD56+ uterine NK cells and CD8+ T lymphocytes in the decidua (70% of all CD3+ cells). In the case of pre-eclampsia without fetal growth retardation (n=14) no increase in CD56+ uterine NK cells was seen, while CD8+ T lymphocytes were significantly increased compared with the normal level (50% of all CD3+ cells). Fetal growth retardation is associated with poor transformation of spiral arteries and characterized by an increase of uterine NK cells. Symptoms of pre-eclampsia are independently associated with an increase in the cytotoxic T subset of decidual lymphocytes. Pre-eclampsia and related fetal growth retardation are seemingly caused by an enhancement of the maternal cytotoxic defence against the fetal allograft.

Aberrant positioning of trophoblast and lymphocytes in the feto-maternal interface with pre-eclampsia.

AIMS To measure maternal serum interleukins (IL) in pregnancy, delivery and early puerperium, and to identify their potential determinants. METHODS Prospective longitudinal measures of serum IL-1 beta, IL-6 and IL-8 in 38 healthy pregnant women at antenatal visits, through labor and delivery, with clinical correlates (infection, vaginal hemorrhage and anemia) recorded by questionnaire. RESULTS Pregnancy IL levels remained consistently low. IL-1 beta increased shortly before delivery, then returned to pregnant levels, except where blood loss exceeded 500 ml. IL-6 and IL-8 rose at labor onset and exceeded pregnancy levels through postpartum day three. Postpartum IL-6 was higher after non-elective cesarean section than after spontaneous delivery (P < 0.0001), and where blood loss exceeded 500 ml. IL-6 and IL-8 were higher with systemic infection during delivery (P < 0.0001) and on postpartum day one (P < 0.05); IL-8 was higher in anemia (delivery: P < 0.005; postpartum day 1: P < 0.05). Differences due to delivery mode and systemic infection remained significant after correction for other conditions. CONCLUSIONS Labor-dependent inflammation increases all IL levels at delivery. Further studies with larger sample sizes are required to establish reference values differentiating physiology from pathology as an aid to peripartum management.

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Gundula Hebisch

Papers

Reference resistance indices of the umbilical, fetal middle cerebral and uterine arteries at 24–42 weeks of gestation

Salivary α-amylase levels after yohimbine challenge in healthy men

Rescue by birth: defective placental maturation and late fetal mortality.

Aberrant positioning of trophoblast and lymphocytes in the feto-maternal interface with pre-eclampsia.

Maternal serum interleukin-1β, -6 and -8 levels and potential determinants in pregnancy and peripartum