Histochemical evaluation of placental dipeptidyl peptidase IV (CD26) in pre-eclampsia: enzyme activity in villous trophoblast indicates an enhanced likelihood of gestational hypertensive disorders.

PROBLEM: To determine whether differences in placental dipeptidyl peptidase IV (DPP IV, CD26) activities occurred in hypertensive complicated pregnancies as compared with uncomplicated pregnancies. METHOD: DPP IV activity was detected with H-Gly-Pro-4M2NA as the substrate in placental cryostat sections from 65 patients with gestational hypertension and 67 patients with uncomplicated pregnancies. The graduated intensities of the reaction product in the villous trophoblast were scored semiquantitatively by light microscopy and were related to the relative frequencies of hypertensive disorders (proportional odds model). After detection of enzyme activity, the same tissue samples were homogenized and used for kinetic fluorometric measurements. RESULTS: Enhanced villous trophoblastic DPP IV activity was significantly associated with an increased frequency of proteinuric hypertension in pregnant women (cumulative odds ratio theta1 = 1.6; P < 0.01). CONCLUSION: This study demonstrates for the first time that increased villous trophoblastic DPP IV activity indicates an increased likelihood of the presence and of the severity of hypertensive disorders in pregnancy.

Histochemical evaluation of placental angiotensinase A in pre-eclampsia: enzyme activity in villous trophoblast indicates an enhanced likelihood of gestational proteinuric hypertension.

The aim of this study was to examine whether differences in placental angiotensinase A (glutamyl aminopeptidase, EC 3.4.11.7) activities occurred in hypertensive complications of pregnancy compared with uncomplicated pregnancies. Biochemical and semiquantitative histochemical methods were used and compared for their applicability. Angiotensinase A activity was detected using L-alpha glutamyl-4-methoxy-2-naphthylamide (alpha-Glu-MNA) as substrate and Fast Blue B salt for simultaneous azo-coupling in cryostat sections of placental tissue samples from 32 patients with pre-eclampsia, 11 patients with pregnancy-induced hypertension and 44 participants with uncomplicated pregnancies. The graduated intensity of reaction product in the villous trophoblast and in fetal blood vessels was evaluated semiquantitatively in a double-blind study by light microscopy (semiquantitative score method). Score levels were related to relative frequencies of hypertensive disorders (proportional odds model) and correlated to the severity of gestational hypertension (Spearman's rank correlation). After detection of enzyme activity, the same tissue samples were homogenized and used for kinetic fluorometric measurements under the same substrate and buffer conditions as in enzyme histochemistry. Enhanced villous trophoblastic angiotensinase A activity was significantly associated with an increased frequency of pre-eclampsia in pregnant women (cumulative odds ratio x 0(1) 6.37; P < 0.001) and showed significant correlations with the severity of gestational hypertensive disorders, represented by systolic (r = 0.31; P < 0.05) and diastolic (r = 0.34; P < 0.05 blood pressure and by concomitant proteinuria (r = 044; P < 0.01). Histochemical evaluation of fetal blood vessels and biochemical measurements revealed no statistically significant results. In conclusion this study demonstrates for the first time that increased villous trophoblastic angiotensinase A activity indicates an increased likelihood of the presence of pre-eclampsia and the severity of hypertensive disorders in pregnancy.

The extravascular contractile system in the human placenta. Morphological and immunocytochemical investigations.

In the human placenta, besides the fetal blood vessel system a second extravascular contractile system exists. It is localized in the chorionic plate and runs in a longitudinal direction and adjacent to fetal blood vessels into the stem villi, where it forms perivascular contractile sheaths. Characteristically, cells of the extravascular contractile system are extremely long and spindle-shaped and give rise to fine cell processes, by which they obviously contact each other or insert into the basement membrane of the trophoblast. They show immunoreactivity with desmin, vimentin, alpha-actin, myosin, nitric oxide synthase type I (brain form) and dipeptidyl peptidase IV. The ultrastructure suggests that cells of the extravascular contractile system are related to smooth muscle cells, including subpopulations with myofibroblastic features. In stem villi a few cells are nitric oxide synthase type I immunoreactive. These cells are thought to be specialized smooth-muscle-like cells of the extravascular contractile system or cells of the extravascular contractile system related to paraneurons that generate nitric oxide, which, in turn, may modulate the tone of perivascular contractile sheaths. The high dipeptidyl peptidase IV activity suggests that modulation of the extravascular contractile system may also occur by substance P.

Effects of the synthetic glucocorticoid triamcinolone acetonide on vasoactive hydrolases of the human placenta in vitro.

Therapy with glucocorticoids during pregnancy is still debated. Previously reported effects of glucocorticoid application in rats resemble certain symptoms of preeclampsia. Therefore, we studied in vitro the effects of the synthetic glucocorticoid triamcinolone acetonide soluble (0.1-10 mM) on placental alpha-glutamyl amino-peptidase, microsomal alanyl aminopeptidase, dipeptidyl peptidase IV, acetylcholinesterase and butyrylcholinesterase in purified trophoblast monolayers and villous explants from first trimester (n = 5) and term placentae (n = 9) using bio- and histochemical methods. In term placentae quantitative histochemistry (microdensitometry) of trophoblast monolayers revealed an increase of alpha-glutamyl aminopeptidase and microsomal alanyl aminopeptidase activity up to 149% and 126% respectively, after treatment with supraphysiological doses. In trophoblast monolayers from first trimester alpha-glutamyl aminopeptidase activity was not affected, whereas microsomal alanyl aminopeptidase activity increased by 25%. Dipeptidyl peptidase IV staining was reduced to 26%. Biochemical measurements of alpha-glutamyl aminopeptidase and microsomal alanyl aminopeptidase activity in homogenates of cultured villi revealed effects similar to those found by microdensitometry in trophoblast monolayers. In contrast, dipeptidyl peptidase IV activity increased in explants of term placentae by 47%. Acetyl- and butyrylcholinesterase activities were reduced in term placental villi by 38% and 40%, respectively. The data indicate that glucocorticoids may affect the activity of hydrolases which are thought to be involved in local placental blood pressure modulation.

[The extravascular contractile system of the human placenta: a new aspect for function of the organ?]. / Das extravasale kontraktile System der Humanplazenta: Ein neuer Aspekt für die Funktion des Organs?

In the chorionic plate and stem villi of the human placenta besides the fetal blood vessel system a second extravascular contractile system (EVCS) exists. The cells of this system contain contractile and intermediate filaments and are dipeptidyl peptidase-IV- and NO-synthase-type-I-(NOS)-immunoreactive. Therefore it can be assumed that these cells cleave the vasodilator Substance P (by DPP IV) and produce NO (by NOS) and may contribute to a modulation of the EVCS.

Enzyme histochemical evidence for the presence of potential blood pressure regulating proteases in cultured villous explants from human first trimester placentae.

The proteases dipeptidyl peptidase IV, angiotensinase A and microsomal alanyl aminopeptidase are present in the human term placenta where they may be involved in the local modulation of placental blood pressure. In order to establish an in vitro model system to study the significance of these proteases in disorders related to pregnancy-induced hypertension, the activity of the proteases was localized histochemically in cultured explants of villi from human first trimester placentae. These studies revealed a similar distribution pattern of the activity of the proteases of cryostat sections of first trimester placental villi and in cultured tissue of the same placentae. Dipeptidyl peptidase IV and angiotensinase A activity were present in cytotrophoblast cells and dipeptidyl peptidase IV activity was found in the syncytiotrophoblast, respectively. Additionally, the activity of the proteases was visualized in various populations of stromal cells. Comparing our results with former studies, the protease activity pattern in first trimester placentae was found to be the same as in term placentae. Despite morphological changes of the tissue after 14 d in culture the localization of the proteases remained unchanged up to 52 d of culture. The results suggest that placental explants may serve as a suitable in vitro model for experimental studies on the role of proteases in pregnancy-induced hypertension.

[Treatment of severe hypertension in pregnancy]. / Behandlung der schweren Hypertonie in der Schwangerschaft.

Treatment of severe hypertension in pregnancy, particularly in preeclampsia and eclampsia, is a great challenge to the obstetrician and requires prompt and expert management. Application of antihypertensive agents is limited during pregnancy because of possible side effects, particularly impairment of the fetal state. The following survey present a detailed discussion on the substances suitable for treating hypertensive emergencies in pregnancy and their side effects. Despite restricted therapeutic possibilities, safe and successful treatment of severe hypertension during pregnancy can best be performed with dihydralazine and diazoxide, which achieve their effect by reducing the peripheral vascular resistance. If the blood pressure cannot be adequately reduced with these substances, treatment can be continued with sodium nitroprusside. A critical discussion is presented in this connection on drugs such as clonidine and reserpine, which reduce pressure largely by central mechanisms and should no longer be applied in pregnant patients because of serious disadvantages. Consideration is also given to the special clinical problems associated with pheochromocytomas, and a concluding discussion deals with the perspectives of antihypertensive therapy in pregnancy.

Variability of arterial blood pressure in normal and hypertensive pregnancy.

In normal pregnancy the circadian blood pressure rhythm is similar to that in the non-pregnant state, with the highest blood pressure values in the morning and the lowest at midnight. This rhythm is lost in patients with pre-eclampsia. Women with severe pre-eclampsia show a reversed circadian rhythm, with a nocturnal increase in blood pressure during the sleeping phase. Although the reasons for this nocturnal hypertension in severe pre-eclampsia are poorly understood, the results suggest that pre-eclamptic women are endangered by hypertensive emergencies, mostly at night. Therefore blood pressure measurement should be extended to the night, and antihypertensive treatment must be adapted to the demands of a reversed circadian rhythm in relevant subgroups of patients.

[Liver diseases complicating pregnancy]. / Komplikative Lebererkrankungen in der Schwangerschaft.

Liver disease in pregnancy represents a broad spectrum of disorders. Most of the common forms of acute and chronic liver disease occur during pregnancy and often present special difficulties in diagnosis and management. In addition, there is a group of hepatic disorders unique to pregnancy, which also must be identified appropriately. Rapid institution of therapy is important in preventing the unfavorable perinatal outcome and maternal mortality. The changes in liver function related to gestation will be reviewed initially. The major forms of hepatic disease specifically associated to pregnancy will be then described and the obstetrical management as well as the therapeutic modalities proposed.

[New aspects of anticonvulsive therapy in severe pre-eclampsia and eclampsia]. / Neue Gesichtspunkte der antikonvulsiven Therapie bei schwerer Präeklampsie und Eklampsie.

Parenterally administered magnesium is a reliable and effective treatment to prevent and control convulsions associated with preeclampsia and eclampsia. Because of several side effects in the newborn, especially in the premature child, benzodiazepines are not recommended for prolonged medication. Clomethiazole has also been used with good acceptance, but clinical experience is limited. The anticonvulsive property of magnesium is not clearly understood. Beside a well known peripheral action by neuromuscular blockade through very high serum concentrations, a central mechanism is postulated already at lower levels. The two most widely used regimens of magnesium administration are the intravenous/intramuscular (i.v./i.m.) method popularized by Pritchard and the continuous intravenous (i.v.) route recommended by Zuspan. The concentrations of magnesium in the serum achieved with the i.v./i.m. regimen are significantly higher than those produced by the i.v. administration, especially in the first three hours after initiation of the treatment and if a maintenance dose of 1 g/h is chosen. Although therapeutic concentrations of magnesium effective to prevent seizures have been reported between 1.3 and 4.0 mmol/l, repeated convulsions are occasionally seen during i.v. regimen and at concentrations below 2 mmol/l. Because of this observation, a maintenance dose of 2 g/h and in some cases 3 g/h is required during the first hours of treatment. Side effects in mother and newborn are low, if there is no renal impairment and the treatment instructions are strictly followed. Respiration as well as urinary output have to be monitored at periodic intervals and the patellar reflex should be present. Calcium gluconate, 10 ml of a 10% solution, is an effective antidote in case of magnesium intoxication.

Relationship between serum prolactin concentration, vascular angiotensin sensitivity and arterial blood pressure during third trimester pregnancy.

Prolactin may play an important role in the pathogenesis of pregnancy-induced hypertension (PIH) and preeclampsia. In 105 normotensive nulliparous women at 28 to 32 weeks of gestation, the relationship between serum prolactin concentration (PRL) and blood pressure behaviour was examined under standardized conditions. Neither postural change from left lateral to supine recumbency nor the infusion of low doses of angiotensin-II-amide had an effect on PRL levels. Similar mean PRL levels were found in pregnant women with a low angiotensin pressor dose (ADP less than 10 ng x kg-1 x min-1) or "angiotensin sensitivity", a positive supine pressor response (delta pd greater than or equal to 20 mmHg) or an increased serum uric acid concentration (greater than 3.6 mg/dl), which are criteria for an increased risk of developing hypertensive complications. However, in the group of subjects with angiotensin sensitivity, a significant correlation was found (a) between PRL levels and the APD and (b) between PRL levels and diastolic blood pressure increase after 5 min of supine recumbency. These results may reflect diminished dopaminergic activity in the central nervous system, which could influence both blood pressure and prolactin secretion.

[Recklinghausen disease and pregnancy]. / Morbus Recklinghausen und Schwangerschaft.

Morbus Recklinghausen is an autosomal dominant disease with a high rate of new mutations. Progression of the skin lesions and the development of severe preeclampsia are the most important complications during gestation. In the following paper three cases with Recklinghausen's disease in pregnancy are reported and the consequence of the complications as well as the importance of genetic counseling are discussed.

[Effect of oxytocin on renin activity and aldosterone concentration in plasma as well as blood pressure in late pregnancy and early puerperium]. / Wirkungen von Oxytozin auf Reninaktivität und Aldosteronkonzentration im Plasma sowie den Blutdruck in der Spätschwangerschaft und im frühen Wochenbett.

The effects of a low-dose oxytocin infusion on blood pressure during late pregnancy and early puerperium are unclear, and its effects on the renin-aldosterone axis are unknown. The present investigation was performed in 24 pregnant subjects at term and in 14 women within five days after vaginal delivery, 10 and 7 of these subjects serving as controls (5% laevulose being infused without oxytocin). A slight but significant decrease of plasma renin activity was found during oxytocin infusion antepartum as well as postpartum. The decrease of aldosterone concentration in plasma was also significant during late pregnancy, but not during the puerperium. An increase of diastolic blood pressure was only observed antepartum. In summary, however, the changes of blood pressure, renin and aldosterone described in the perinatal period in normotensive subjects were small and without clinical importance.

The value of the mean arterial blood pressure in the second trimester (MAP-2 value) as a predictor of pregnancy-induced hypertension and preeclampsia. A preliminary report.

In 200 healthy nulliparous women the mean arterial blood pressure in the second trimester (MAP-2 value) was calculated. 85 women (42 %) had a MAP-2 value of greater than or equal to 90 mmHg (positive test result), but only 27 women (32 %) developed a hypertensive complication. Conversely, 113 of the 115 (98 %) women with a negative test result (MAP-2 value less than 90 mmHg) remained normotensive. Only two women of this group (2 %) later showed a mild pregnancy-induced hypertension. Thus, the MAP-2 value has a high sensitivity (93 %) and a high predictive value of negative test results (98 %). On the other hand, there is a high rate of false-positive results (68 %) and thus a low predictive value of positive test results (32 %). It is concluded that the MAP-2 value is a simple method for selecting pregnant women who should be examined with other more specific predictive tests. Alternatively, weekly measurements of blood pressure are recommended for early diagnosis of hypertensive disorders of late pregnancy in all women with a MAP-2 value of 90 mmHg or more.

[The value of a single determination of serum uric acid concentration in the early diagnosis of hypertensive disorders in pregnancy (author's transl)]. / Die Aussagekraft einer einmaligen Bestimmung der Harnsäurekonzentration im Serum zur Früherfassung der hypertensiven Schwangerschaftskomplikationen.

In 200 healthy, normotensive nulliparous women, a single determination of serum uric acid concentration was done between weeks 28-32 of gestation in order to identify a possible increased risk of developing hypertensive complications. If serum concentrations higher than 3.6 mg/dl were considered as increased ("positive test"), women who developed toxaemia of late pregnancy (proteinuric hypertension), had a significantly elevated mean serum uric acid concentration already at the beginning of the third trimester (p less than 0.01). The incidence of toxaemia and hypertensive disease without proteinuria was significantly higher in the group of women with an elevated uric acid value (p less than 0.001). Only 9% of pregnant women with a "negative test" ultimately developed a mild form of a hypertensive complication. Conversely, 74% of the patients with a "positive test" remained normotensive. Thus, the predictive value of a "positive test" is low (26%) and that of a "negative test" relatively high (91%).

Inhibition of the renin--aldosterone axis and of prolactin secretion during pregnancy by L-dopa.

Recently, interactions between dopaminergic mechanisms and aldosterone secretion were described in non-pregnant subjects. The present study examined the effect of 1000 mg of L-dopa by mouth on plasma renin activity (PRA), and the concentrations of plasma aldosterone (PA) and prolactin (PRL) during normal pregnancy. Under basal conditions, there was a clear decrease of PRA, PA and PRL 60 min after oral intake of L-dopa in seven subjects; a further decrease was observed during the following 45 min, resulting in a total decrease of 41 (PRA), 44 (PA) and 56 (PRL) % of the respective arithmetic mean of the basal values. However, the response of PA to isopressor angiotensin II infusions was comparable before and shortly after treatment with L-dopa in 16 pregnant subjects. The decreased activity of the renin-aldosterone axis after administration of L-dopa may be attributed to an accumulation of dopamine and catecholamines in the brain, resulting in a diminution of sympathetic outflow from the central nervous system. The simultaneous and comparable changes of both PRA and PA after L-dopa treatment, as well as the reversibility of aldosterone suppression by infusion of angiotensin II, suggest that the inhibition of aldosterone secretion by L-dopa is mediated by a decrease of renin release.

Effect of angiotensin infusion during pregnancy on fetal heart rate and on fetal activity.

The angiotensin sensitivity test is of value in predicting patients at increased risk of pregnancy-induced hypertension and preeclampsia. Studies on the effects of angiotensin II on uterine blood flow in various species showed contradicting results. In the present study, 15 pregnant women were monitored by cardiotocography before, during and after an infusion of angiotensin II-amide (maximal infusion rates 6.3--23.2 ng . kg-1. min-1). No remarkable changes in fetal heart rate, oscillatory frequency and amplitude, as well as in the number of accelerations and fetal movements could be observed. It may be concluded from these results that the fetal condition is not compromised by an angiotensin sensitivity test.

[Significance of blood pressure and body weight in the early diagnosis of gestosis. Preliminary report]. / Bedeutung des Blutdruck- und Gewichtsverhaltens bei der Frühdiagnose der Gestose Ein vorläufiger Bericht.

Mean weight gain is higher in gestosis than in normal pregnancy. On the other hand, many patients with gestosis had an insignificant increase in body weight. Therefore, the weight gain in pregnancy does not have a predictive value concerning the later risk of developing gestosis. The supine pressor test ("roll-over test") and the determination of mean arterial pressure during weeks 18 to 26 of gestation (MAP-II-value) are simple and appropriate methods for early diagnosis of gestosis. By using the supine pressor test or by determination of the MAP-II-value, 73% or over 90%, respectively, of all subjects with later gestosis could be recognized before the onset of first clinical symptoms of the disease (n = 108). As both methods frequently show false-positive results, a high percentage of pregnant women needs intensive care during the last trimester. In order to select further women with increased risk of gestosis, it is proposed to calculate the MAP-II-value first and to determine the supine pressor response at least in those primigravidae with a MAP-II-value of 90 mmHg or more.