Pharmacologic treatment of hypertensive disorders during pregnancy

Vasorelaxant effect of monoterpene carvacrol on isolated human umbilical artery

Carvacrol is the main compound of essential oils extracted primarily from Thymus and Origanum species. Its various biological activities were confirmed: antioxidant, anti-inflammatory, antibacterial, antifungal, anti-tumour, antinematodal and vasorelaxant action. Although vasodilation mediated by carvacrol was previously described, the exact mechanism of its action has not yet been established. Hence, the aim of this study was to investigate carvacrol vasoactivity on human umbilical arteries (HUA) and different pathways involved in its mechanism of action using tissue bath methodology. Carvacrol caused a significant decrease in vascular tension of 5-HT-pre-contracted umbilical arteries, with EC50 of 442.13 ± 33.8 µM (mean ± standard error of the mean - SEM). At 300 µM, carvacrol shifted downward the 5-HT concentration-response curve with statistical significance of p < 0.001 obtained for the four highest concentrations. At concentration of 1 mM, carvacrol completely abolished BaCl2-induced contraction in Ca2+-free Krebs-Ringer bicarbonate solution (p < 0.001). Isopentenyl pyrophosphate, the antagonist of TRPV3 channel, was able to decrease the efficacy of carvacrol (p < 0.001). The vasorelaxant effect of carvacrol seems to involve the blocking of L-type of Ca2+ channels on smooth muscle cells. However, the role of TRPV3 channels in carvacrol-induced vasodilation of HUA cannot be excluded either.

Relaxant Effect of Monoterpene (-)-Carveol on Isolated Human Umbilical Cord Arteries and the Involvement of Ion Channels

Carveol is a monoterpene present in the structure of many plant products. It has a variety of biological activities: antioxidant, anticancer and vasorelaxation. However, studies investigating the effect of monoterpenoids on human vessels have not yet been described. Thus, the present study aimed to characterize the effect of (−)-carveol on human umbilical arteries (HUAs). HUA ring preparations were isolated and subjected to isometric tension recordings of umbilical artery smooth muscle contractions. (−)-Carveol exhibited a significant vasorelaxant effect on KCl and 5-HT-induced contractions, obtaining EC₅₀ values of 344.25 ± 8.4 and 175.82 ± 4.05 µM, respectively. The participation of calcium channels in the relaxation produced by (−)-carveol was analyzed using vessels pre-incubated with (−)-carveol (2000 µM) in a calcium-free medium, where the induction of contractions was abolished. The vasorelaxant effect of (−)-carveol on HUAs was reduced by tetraethylammonium (TEA), which increased the (−)-carveol EC₅₀ to 484.87 ± 6.55 µM. The present study revealed that (−)-carveol possesses a vasorelaxant activity in HUAs, which was dependent on the opening of calcium and potassium channels. These results pave the way for further studies involving the use of monoterpenoids for the vasodilatation of HUAs. These molecules have the potential to treat diseases such as pre-eclampsia, which is characterized by resistance in umbilical arteries.

Pregnancy outcomes of expectant management of stable mild to moderate chronic hypertension as compared with planned delivery

OBJECTIVE

To compare outcomes between elective delivery at 37 weeks of pregnancy and expectant management among pregnant women with mild to moderate chronic hypertension.

METHODS

In a two-center study, 76 women with mild to moderate chronic hypertension were randomly allocated to planned delivery at 37 completed weeks (group A) or expectant management for spontaneous onset of labor or reaching 41 weeks (group B) between April 2012 and October 2013. Differences were compared by t test, χ(2) test, or Fisher exact test. Odds ratios (ORs) with 95% confidence interval (CIs) were determined.

RESULTS

There were no differences in superimposed pre-eclampsia (SPE), severe hypertension, preterm delivery, placental abruption, oligohydramnios, intrauterine growth restriction, or perinatal mortality between the groups. Group B had higher gestational age at delivery (P=0.001) and birth weight (P=0.01), but lower cesarean (OR 3.4; 95% CI, 1.2-10.3; P=0.03) and neonatal care unit admission (OR 5.4; 95% CI, 1.4-21.0; P=0.01) rates. More women with SPE were diagnosed before than after 37 weeks in group B (P=0.01). Overall, patients who developed SPE had more adverse pregnancy outcomes than those who did not.

CONCLUSION

Mild to moderate chronic hypertension could be managed expectantly up to 41 weeks if SPE did not develop.

Current and future pharmacological treatment strategies with regard to aortic disease in Marfan syndrome

INTRODUCTION

Marfan syndrome is a multisystemic connective tissue disorder caused mainly by mutations in the fibrillin-1 gene. The entire cardiovascular system is affected in patients with Marfan syndrome. Aortic root dilatation, aortic valve regurgitation or - the most feared and life-threatening symptom - aortic root dissection are the most common manifestations. Therapeutic strategies, such as prophylactic aortic root surgery and pharmacological therapy, focus on the prevention of aortic dissection. Currently, the standard medicinal treatments targeting aortic dilatation and dissection consist of agents generally used to lower blood pressure and/or the inotropic state of the heart. By these means, the cyclic repetitive forces exerted on the aortic wall are diminished and thus the onset of aortic dilatation is potentially prevented. Although these pharmacological agents may offer some benefit in reduction of aortic aneurysm expansion rate, they do not target the underlying cause of the progressive aortic degradation.

AREAS COVERED

This review discusses the effectiveness of frequently prescribed medications used to prevent and delay aortic complications in Marfan syndrome. New insights on the biochemical pathways leading to aortic disease are also discussed to highlight new targets for pharmacological therapy.

EXPERT OPINION

Recent insights in the transforming growth factor beta signaling pathway and inflammatory mechanisms in a well-established mouse model of Marfan syndrome, have led to studies exploring new pharmacological treatment strategies with doxycycline, statins and angiotensin II receptor blockers. Pharmacological therapy is focused more on prevention than on delay of aortic wall pathology in Marfan syndrome. Of the new pharmacological treatment strategies targeting aortic pathology in Marfan syndrome, angiotensin receptor type 1 blockers are promising candidates, with several clinical trials currently ongoing.

Hypertension complicating diabetic pregnancies: pathophysiology, management, and controversies

Hypertensive disorders of pregnancy (HDP), including pre-existing hypertension, gestational hypertension, and preeclampsia, further complicate already high-risk pregnancies in women with diabetes mellitus (DM). Women with both pre-existing and gestational diabetes are at increased risk for HDP, leading to higher maternal and fetal morbidity. Further, particularly in diabetic women and women with a history of gestational diabetes, HDP significantly increases the risk for future cardiovascular events. For clinicians, women with hypertension and diabetes during pregnancy pose a management challenge. Specifically, preconception management should stress strict control of glycemia, blood pressure, and prevention of diabetic complications, specifically nephropathy, which specifically increases the risk for preeclampsia. During gestation, clinicians must be aware of potential maternal and fetal complications associated with various anti-hypertensive therapies, including known fetotoxicity of ACE inhibitors and ARBs when given in the 2nd or 3rd trimester, and the risks and benefits of expectant management versus delivery in cases of severe gestational hypertension or preeclampsia. Indeed, diabetic women must be followed closely prior to conception and throughout gestation to minimize the risk of HDP and its associated complications.

Mortalidade materna por eclâmpsia

OBJETIVO: analisar fatores associados à mortalidade materna causada por eclâmpsia. MÉTODOS: estudo de coorte retrospectivo revisando-se prontuários médicos dos partos assistidos no Conjunto Hospitalar de Sorocaba (janeiro/1995 a dezembro/2005). Variáveis pesquisadas: ano do parto, características sócio-demográficas maternas, antecedentes familiares, pessoais e obstétricos, características da gestação, parto, puerpério, atendimento realizado, evolução e condições de alta. A análise estatística incluiu teste exato de Fisher, correlação de Pearson, e regressão múltipla de Poisson. RESULTADOS: registraram-se 35.973 partos, 179 casos de eclâmpsia, 52 com sérias complicações, 23 com maior permanência no tratamento intensivo e 8 evoluíram para óbito. A proporção de eclâmpsia decresceu no período (0,90% para 0,37%; r= - 0,746; p=0,008), mas mantendo a proporção de casos com sérias complicações (0,25% para 0,17%, r= - 0,45; p=0,162). A proporção de óbitos foi maior entre pacientes não brancas (RR=9,10; IC95%=1,83-45,23; p=0,007) e menor entre as tratadas com sulfato de magnésio (RR=0,08; IC95%=0,02-0,35; p= 0,001). CONCLUSÕES: reduziu-se a proporção de eclâmpsia entre os partos assistidos no Conjunto Hospitalar de Sorocaba, porém, a eclâmpsia continua sendo importante causa de óbito materno na região. Este estudo revela que é fundamental o aperfeiçoamento das medidas de diagnóstico precoce e tratamento da pré-eclâmpsia e eclâmpsia pela rede de atenção à saúde.

Anti-Hypertensive Drugs Alter Cytokine Production from Preeclamptic Placentas and Peripheral Blood Mononuclear Cells

OBJECTIVE

Antihypertensive drugs are administered to women with preeclampsia to control blood pressure and fluid overload. Whether they modulate placental or circulating cytokine production in women with preeclampsia is unknown. This study examines the effect of pharmacological doses of antihypertensive drugs on the production of IL-10, tumor necrosis factor alpha (TNF-alpha), and IL-6 in placental tissue and peripheral blood mononuclear cells (PBMCs) from women with preeclampsia.

METHODS

Term placenta samples (n = 6) and PBMCs from whole blood (n = 6) were obtained from women with preeclampsia. Both villous explants and PBMCs were cultured with increasing concentrations of antihypertensive drugs (clonidine, diazoxide, hydralazine, and furosemide). The dose effect of drugs on the production of placental and circulating cytokines IL-10, TNF-alpha, and IL-6 was examined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our data suggest that clonidine can stimulate anti-inflammatory IL-10 production from PBMC while decreasing pro-inflammatory TNF-alpha, whereas low doses of hydralazine increased the production of IL-10, TNF-alpha, and IL-6 from preeclamptic PBMCs. There was a reduction in IL-10, TNF-alpha, and IL-6 production with increasing doses of clonidine and hydralazine by placentas in preeclampsia. IL-10, TNF-alpha, and IL-6 production from preeclamptic placenta and PBMCs were inhibited by diazoxide and furosemide.

CONCLUSIONS

Antihypertensive drugs may alter Th1/Th2 cytokine balance in preeclamptic tissues in vitro.

Medication use during pregnancy and the risk of childhood cancer in the offspring

The young age at onset of many cancers in childhood has led to investigations on maternal exposures during pregnancy. Data from a population-based case-control study in Germany (1992-1997) that included 1,867 cases and 2,057 controls was used to investigate this question. Maternal use of vitamin, folate or iron supplementation was associated with a reduced risk of non-Hodgkin lymphoma and tumors and, less clearly, with leukemia, but not with CNS tumors. An increased risk of neuroblastoma was associated most markedly with diuretics and other antihypertensives, but also with vitamin, folate or iron supplementation. No associations were seen with pain relievers, antinauseants or cold medications, nor with delivery by Caesarian section. The strengths of this study are its population base, the large number of cases and the inclusion of different case groups to identify disease specificity of associations. The limitation of this study is an exposure assessment relying on maternal self-reports. In conclusion, these data indicate a potential influence of some maternal medication during pregnancy on the risk of childhood cancer in the offspring; however, no clear picture is seen.

Antihypertensive drugs clonidine, diazoxide, hydralazine and furosemide regulate the production of cytokines by placentas and peripheral blood mononuclear cells in normal pregnancy

BACKGROUND

Antihypertensive drugs such as clonidine, diazoxide, hydralazine and furosemide are used in the hypertensive disorders of pregnancy to control blood pressure, but it is not clear if they modulate the production of placental or circulating cytokines.

OBJECTIVE

To examine the effect of pharmaceutical doses of well known antihypertensive drugs used for blood pressure control on the production of the cytokines interleukin (IL)-6, IL-10 and tumour necrosis factor (TNF)-alpha in placental tissue and peripheral blood mononuclear cells (PBMCs) in normal pregnancy.

DESIGN

Placental biopsies were taken from the decidual surface of placentas after delivery of normal pregnancies (n = 6) and PBMCs were separated from the whole blood of normal term pregnant women (n = 7). Both villous explants and PBMCs were cultured with increasing concentrations of antihypertensive drugs. The dose effect of drugs on the production of placental and circulating cytokines (IL-6, IL-10 and TNF-alpha) were examined by enzyme-linked immunosorbent assay.

RESULTS

Placental production of IL-10 was not affected by clonidine, but decreased significantly after incubation of the tissue with diazoxide, hydralazine or furosemide. Production of IL-10 by PBMCs increased significantly: by from 3.4 +/- 2.7% [16.3 pg/ml (range 6.1-21.5 pg/ml)] to 24.5 +/- 3.3% [30.4 pg/ml (range 16.9-34.8 pg/ml)] with increasing concentrations of clonidine (0.08-1.3 microg/ml), and by 8.8 +/- 3.5% [4.1 pg/ml (range 3.0-17.8 pg/ml)] and 17.2 +/- 1.9% [22.6 pg/ml (range 13.2-23.2 pg/ml)] with lower doses of hydralazine (6.3 and 12.5 microg/ml) (all P values < 0.05). There was a stepwise reduction in production of TNF-alpha and IL-6 with increasing doses of diazoxide, hydralazine and furosemide by placentas and PBMCs from these women with normal pregnancies.

CONCLUSION

Our data suggest that the antihypertensive drugs clonidine and hydralazine can stimulate production of the circulating anti-inflammatory cytokine IL-10, whereas furosemide and diazoxide inhibit the production of this cytokine and the proinflammatory cytokines TNF-alpha and IL-6 by placentas and PBMCs.