H. Schröcksnadel

Decreased plasma tryptophan in pregnancy

Objective To examine levels of serum tryptophan and its degradation product kynurenine in uncomplicated pregnancy, according to the week of pregnancy and the concentrations of neopterin. Methods Plasma was analyzed from 45 healthy pregnant women (15 in each trimester), 15 healthy puerperas, and 20 nonpregnant controls. Tryptophan and kynurenine were measured by reverse-phase, high-performance liquid chromatography, and neopterin by radioimmunoassay. Results In healthy pregnant women, tryptophan values decreased (median first trimester: 72 μmol/L; second trimester: 51 μmol/L; third trimester: 46 μmol/L; P < .001) in a manner correlated with the duration of pregnancy (Spearman rank correlation coefficient rs = −0.771, P < .001) and normalized in the puerperium (median 60 14mol/L). No change in kynurenine, a tryptophan degradation product, was observed, but the ratio of kynurenine to tryptophan increased during pregnancy and correlated positively with gestational age (rs = 0.714, P < .001). In addition, an inverse correlation existed between neopterin and tryptophan concentrations (rs = −0.566, P < .001), as well as a positive one between neopterin and the kynurenine to tryptophan ratio (rs = 0.660, P < .001). Conclusion Tryptophan levels decrease during normal pregnancy and the decrease may be related to immune activation phenomena.

Longitudinal study of tryptophan degradation during and after pregnancy

In mice, activation of indoleamine-2,3-dioxygenase (IDO), an enzyme converting tryptophan to N-formyl-kynurenine, was found to be necessary requirement to achieve immunotolerance against the fetus and thus uncomplicated pregnancy. In plasma from 20 healthy pregnant women with singleton pregnancies we consecutively analyzed kynurenine and tryptophan concentrations during pregnancy (1 specimen at each trimester of gestation) and postpartum (week 6). None of the women had any signs of infection at the time of plasma sampling, but the study population was otherwise unselected. The kynurenine to tryptophan ratio (kyn/trp) was calculated as an estimate of IDO activity, and data were compared to concentrations of neopterin and 55kD soluble tumor necrosis factor receptor (sTNF-R55), two indicators of immune activation, and to alanineaminotransferase (ALT) levels. Increasing kynurenine and decreasing tryptophan concentrations were found during pregnancy, data suggesting significant degradation of tryptophan. In parallel, increasing concentrations of immune activation markers neopterin and sTNF-R55 were observed, correlating significantly to kyn/trp. The data point to an involvement of cytokine-induced IDO activation in the degradation of tryptophan observed during pregnancy. After pregnancy, sTNF-R55 and also neopterin concentrations declined, whereas tryptophan concentrations increased, indicating that immune activation and activation-induced tryptophan degradation returned to baseline. By contrast, still increased kynurenine concentrations and also increased kyn/trp point to continuing catabolism of tryptophan. Postpartum elevation of liver enzyme ALT may suggest that increased activity of hepatic tryptophan pyrrolase could be involved in increased conversion of tryptophan despite low degree of immune activation. We conclude that IDO is activated in pregnancy and that the decrease of tryptophan might be related to immune activation phenomena. Sustained increase of kynurenine postpartum seems independent from immune activation process.

Tumor markers in hypertensive disorders of pregnancy

Plasma levels of tumor markers (CEA, TPA, CA 15.3, CA 125, alpha-fetoprotein) for 50 patients with hypertensive disorders of pregnancy were compared with those of 50 healthy women with singleton pregnancies and 50 healthy non-pregnant controls. With the exception of CEA all tumor marker values were higher in pregnant women, these differences being statistically significant (all p < 0.0001). Alpha-fetoprotein was lower in hypertensive than in healthy pregnant women (p = 0.0004), whereas CEA, CA 15.3 and CA 125 showed no statistically significant differences. TPA values in patients with hypertensive disorders of pregnancy (median 190 U/l) were 2.7 times higher than those of healthy pregnant controls (median 70.5 U/l) with a statistically significant difference (p < 0.0001). The individual degrees of disease severity demonstrated increasing TPA medians (pregnancy-induced hypertension: 106.5 U/l; pre-eclampsia: 200 U/l; HELLP syndrome: 339 U/l). TPA levels correlated positively with clinical severity of disease and negatively with fetal (rs = -0.58; p < 0.0001) and placental weight (rs = 0.44; p = 0.01).

Pre-eclampsia: a disorder of placental mitochondria?

Pre-eclampsia is a common, pregnancy-induced, multisystem disease leading to severe complications in the mother and foetus. The aetiology of pre-eclampsia remains a mystery, but a growing body of evidence suggests that a mitochondrial defect might cause the impairement of differentiation and invasion of the trophoblast that leads to this disorder. This hypothesis is the topic of ongoing studies that, if confirmed, would be highly relevant to preventative strategies for this disease.

Tryptophan Degradation During And After Gestation

In mice, activation of indoleamine-(2,3)-dioxygenase (IDO), an enzyme converting tryptophan to N-formyl-kynurenine, is required to achieve immunotolerance against the fetus and thus uncomplicated pregnancy. On the other hand, postpartum blues and depression appear to be related to reduced availability of tryptophan and serotonin. In healthy pregnant women with singleton pregnancies we consecutively analyzed kynurenine and tryptophan concentrations during pregnancy and postpartum. The kynurenine to tryptophan ratio (kyn/trp) was calculated as an estimate of IDO activity, and data were compared to concentrations of neopterin and 55kD soluble tumor necrosis factor receptor, two indicators of immune activation, and to alanineaminotransferase (ALT) levels. Increasing kynurenine and decreasing tryptophan concentrations were found during pregnancy. The data confirm earlier results and suggest significant degradation of tryptophan. In parallel, increasing concentrations of immune activation markers neopterin and sTNF-R55 were found, correlating significantly to the kyn/trp. The data point to an involvement of cytokine-induced IDO activation in the degradation of tryptophan observed during pregnancy. After pregnancy, sTNF-R55 and also neopterin concentrations declined, whereas tryptophan concentrations increased, indicating that immune activation and activation-induced tryptophan degradation has ceased. By contrast, still increased kynurenine concentrations and also increased kyn/trp suggest continuing turnover of tryptophan. Because also ALT was increased postpartum, abnormal activity of hepatic tryptophan pyrrolase and possibly other enzymes could be involved. We conclude that the decrease of tryptophan during pregnancy might be related to immune activation phenomena. Sustained increase of kynurenine postpartum seems independent from immune activation process, rather it seems related to abnormal activity of liver enzymes.

Assessment of endothelial preservation in human cell cultures

BACKGROUND Impairment of microcirculation due to endothelial cell damage must be considered a limiting factor in organ preservation. The present study aims at a quantitative assessment of preservation-induced injury in cultured human endothelial cells. METHODS Monolayer cultures of human umbilical vein endothelial cells were exposed to cold (40 degrees C) hypoxic storage in University of Wisconsin solution, histidine-tryptophane-ketoglutarate solution, Euro-Collins solution, and saline solution. Cellular integrity was evaluated by viable cell count, ultrastructural analysis, and prostacyclin release after 24, 48, and 72 hours of storage and subsequent 6 hours of reincubation in culture medium at 37 degrees C. Expression of intercellular adhesion molecule-1 was investigated after 6, 12, and 24 hours of cold preservation and after 6 hours of rewarming. RESULTS Cellular viability was best maintained with University of Wisconsin and histidine-tryptophane-ketoglutarate solutions with no significant reduction of cell count up to 72 hours; Euro-Collins solution and saline solution caused a significant decline in cell numbers after 24 hours (p < 0.05). Morphology was best preserved by University of Wisconsin solution. Prostacyclin values were elevated after 24 hours in Euro-Collins solution and saline solution, after 48 hours in histidine-tryptophane-ketoglutarate, Euro-Collins, and saline solutions, and after 72 hours in Euro-Collins solution (p < 0.05, compared with University of Wisconsin solution). ICAM expression was weak after cold storage (24 hours) in University of Wisconsin solution, moderate after incubation in histidine-tryptophane-ketoglutarate and Euro-Collins solutions and intensive after storage in saline solution. In contrast, rewarming caused intensive expression of intercellular adhesion molecule-1 in all experimental groups as compared with controls, which showed baseline expression at any time. CONCLUSIONS From our results we conclude that in this model cellular integrity is best protected by University of Wisconsin solution, increased prostacyclin release is consistent with morphologic alterations and intercellular adhesion molecule-1 expression is clearly up-regulated in endothelial cells under reperfusion conditions after cold hypoxic storage.

Childbirth as a Biological Model for Stress

Objective: The aims of this investigation were to measure corticotropin-releasing hormone (CRH), corticotropin (ACTH) and cortisol before, during and after delivery searching for an endocrine intercorrelation of the hypothalamic-pituitary-adrenal (HPA) axis and to correlate these findings with obstetrical variables. Methods: Blood was sampled from 50 women with singleton pregnancies at term without uterine contractions, during delivery (after full cervical dilatation) and on the 4th postnatal day. Hormones were measured by radioimmunoassay (RIA). The correlation between obstetric variables, sociodemographic and endocrine data were evaluated using the Spearman rank coefficient. Group comparisons for continuous variables were calculated using the Mann-Whitney U test and Kruskal-Wallis test. Results: Maternal plasma ACTH and cortisol increased significantly during labor, declining toward the 4th postnatal day (p < 0.001) and showing a significant intercorrelation (p < 0.01). Compared to women without uterine contractions CRH rose during labor (p < 0.05) and decreased rapidly to the 4th postnatal day (p < 0.001). No correlations between CRH and ACTH or cortisol were observed. None of the obstetrical variables (parity, newborn’s weight, duration of delivery) revealed any significant correlation with ACTH. Analgetic medication (pethidine hydrochloride) was not able to influence the endocrine response to labor stress. Conclusions: Stressful experience during childbirth has an impact on endocrine response. However, this is not fully evident along the HPA axis in a simple biological model with monocausal dependencies. This ‘biological stress model’ is not sensitive enough to detect different childbirth conditions and the hormones in the maternal compartment have partially fetal (placental) origin.

Gebären im Wasser

Fragestellung und Methoden: In einer retrospektiven Fall-Kontroll-Studie wurden 265 in einer Universitätsklinik und einem Bezirkskrankenhaus in Österreich durchgeführte Wassergeburten (aus Schädellage) und ein auf Alter, Gestationsalter und Parität gematchtes Kollektiv von Spontangeburten (ohne operative Intervention) hinsichtlich der wichtigsten fetomaternalen geburtshilflichen Parameter verglichen. Ergebnisse: 4,3% aller Geburten der Universitätsklinik und 13% der Geburten des Bezirkskrankenhauses fanden im Wasser statt. Österreichische Frauen und Frauen mit höherer Schulbildung waren bei dieser Geburtsform häufiger vertreten. Die Dauer der verschiedenen Phasen der Geburt wurde durch die Entbindung im Wasser nicht wesentlich verändert. Die Nabelarterien-pH-Werte der im Wasser geborenen Kinder (Median 7,29 bzw. 7,35) waren besser als die der Kontrollgruppe (Median 7,26), was auf einer positiven Selektion der im Wasser entbundenen Frauen beruhen dürfte. Die Zahl an Episiotomien im Wasser (14 bzw. 4%) war deutlich niedriger als an Land (48%). Umgekehrt fanden sich im Wasser deutlich mehr Dammrisse 1. und 2. Grades (36 bzw. 41%) und Labienrisse (23 bzw. 21%) als in der Kontrollgruppe (Dammrisse 23%; Labienrisse 7%). Bei im Wasser entbundenen Frauen war weniger Schmerzmedikation nötig (8 bzw. 9%) als in der Kontrollgruppe (64%). Das Hämoglobin im Wochenbett war nach Wassergeburt nicht unterschiedlich zur Kontrollgruppe. Die mütterliche und kindliche infektiöse Morbidität war nach Wassergeburt nicht erhöht. Schlussfolgerungen: Bei gesunder Mutter und gesundem Kind am Termin in Schädellage ist (unter Wahrung entsprechender Kriterien an Abteilungen mit spezifischer Infrastruktur) die Entbindung im Wasser als sicher anzusehen.

Activated cellular immunity and decreased serum tryptophan in healthy pregnancy.

We analyzed plasma samples from 45 randomly selected healthy pregnant women and from 20 healthy nonpregnant female controls of corresponding age. Tryptophan and kynurenine concentrations were measured by reverse-phase high performance liquid chromatography. The kynurenine per tryptophan ratio was calculated to allow a more accurate estimate of tryptophan degradation. In addition, neopterin was measured by radioimmunoassay. There were significantly lower tryptophan concentrations in pregnant women compared to nonpregnant controls. Kynurenine per tryptophan ratios were increased in pregnant women in the 3rd trimester. Significant correlations existed between neopterin increase and tryptophan decrease as well as kynurenine increase and tryptophan decrease. Also significant correlations between week of pregnancy and lower tryptophan and higher kynurenine per tryptophan ratio were found (p < 0.01). From our data, cellular immune activation is likely to be the cause of enhanced tryptophan degradation during pregnancy.

Fulminant recurrence of a Sertoli-Leydig cell tumour during pregnancy

*Martin Widschwendter Training Fellow, tGeri Meduri Research Fellow, tHugues Loosfelt Research Director, *Hans Schriicksnadel Senior Investigator, **A. Hittmair Senior Investigator, *E. Muller-Holzner Senior Investigator, *Alain G. Zeimet Senior Investigator Departments of *Gynaecology and Obstetrics and **Pathology, Universiiy Hospital, Innsbruck, Austria; and TINSERM, Bic2tre Hospital, Cedex. France