Angiotensin-converting enzyme I/D polymorphism and preeclampsia risk: evidence of small-study bias

BACKGROUND: Inappropriate activation of the renin-angiotensin system may play a part in the development of preeclampsia. An insertion/deletion polymorphism within the angiotensin-I converting enzyme gene (ACE-I/D) has shown to be reliably associated with differences in angiotensin-converting enzyme (ACE) activity. However, previous studies of the ACE-I/D variant and preeclampsia have been individually underpowered to detect plausible genotypic risks. METHODS AND FINDINGS: A prospective case-control study was conducted in 1,711 unrelated young pregnant women (665 preeclamptic and 1,046 healthy pregnant controls) recruited from five Colombian cities. Maternal blood was obtained to genotype for the ACE-I/D polymorphism. Crude and adjusted odds ratio (OR) and 95% confidence interval (CI) using logistic regression models were obtained to evaluate the strength of the association between ACE-I/D variant and preeclampsia risk. A meta-analysis was then undertaken of all published studies to February 2006 evaluating the ACE-I/D variant in preeclampsia. An additive model (per-D-allele) revealed a null association between the ACE-I/D variant and preeclampsia risk (crude OR = 0.95 [95% CI, 0.81-1.10]) in the new case-control study. Similar results were obtained after adjusting for confounders (adjusted per-allele OR = 0.90 [95% CI, 0.77-1.06]) and using other genetic models of inheritance. A meta-analysis (2,596 cases and 3,828 controls from 22 studies) showed a per-allele OR of 1.26 (95% CI, 1.07-1.49). An analysis stratified by study size showed an attenuated OR toward the null as study size increased. CONCLUSIONS: It is highly likely that the observed small nominal increase in risk of preeclampsia associated with the ACE D-allele is due to small-study bias, similar to that observed in cardiovascular disease. Reliable assessment of the origins of preeclampsia using a genetic approach may require the establishment of a collaborating consortium to generate a dataset of adequate size

Polymorphisms of the endothelial nitric oxide synthase (NOS3) gene in preeclampsia: a candidate-gene association study

<p>Abstract</p> <p>Background</p> <p>The endothelial nitric oxide synthase gene (<it>NOS3</it>) has been proposed as a candidate gene for preeclampsia. However, studies so far have produced conflicting results. This study examines the specific role of variants and haplotypes of the <it>NOS3 </it>gene in a population of Caucasian origin.</p> <p>Methods</p> <p>We examined the association of three common variants of the <it>NOS3 </it>gene (4b/a, T-786C and G894T) and their haplotypes in a case-control sample of 102 patients with preeclampsia and 176 women with a history of uncomplicated pregnancies. Genotyping for the <it>NOS3 </it>variants was performed and odds ratios and 95% confidence intervals were obtained to evaluate the association between <it>NOS3 </it>polymorphisms and preeclampsia.</p> <p>Results</p> <p>The single locus analysis for the three variants using various genetic models and a model-free approach revealed no significant association in relation to clinical status. The analysis of haplotypes also showed lack of significant association.</p> <p>Conclusions</p> <p>Given the limitations of the candidate-gene approach in investigating complex traits, the evidence of our study does not support the major contributory role of these common <it>NOS3 </it>variants in preeclampsia. Future larger studies may help in elucidating the genetics of preeclampsia further.</p

Fetal and maternal Doppler velocimetry and cytokines in high-risk pregnancy

Objective: Fetal hypoxia and preterm delivery are reported to be strongly associated with brain damage and neurodevelopmental delay. Doppler signs of fetal brain sparing have been described during chronic hypoxia, but whether they are related to brain damage is unknown. The aim of this study was to evaluate if markers of tissue injury, i.e., tumor necrosis factor-alpha. (TNF-alpha) and interleukin-6 (IL-6) are related to signs of increased perinatal vascular impedance and/or fetal brain sparing in high-risk pregnancies. Study design: TNF-alpha and IL-6 levels were evaluated in maternal blood serum of 67 high-risk pregnancies. Serum samples were taken at the time of umbilical, middle cerebral artery and uterine artery Doppler velocimetry examination. The values for TNF-alpha and IL-6 were correlated with reference median values obtained with gestational age in the form of a Z-score. Results: TNF-alpha levels showed values within the normal range in only four cases. IL-6 values were found normal in 14 cases. The Z-score for mean middle cerebral artery pulsatility index (PI) showed a significant correlation to TNF-alpha and IL-6 levels, P < 0.0001 and P < 0.003, respectively. This might suggest a strong correlation between signs of fetal brain sparing and increased maternal serum TNF-alpha and IL-6 levels. Abnormal uterine artery PI and the presence of a "notch" were also highly significantly related to TNF-alpha and IL-6 levels, which were nearly two-fold higher compared to normal uterine artery blood flow and the absence of a "notch". Abnormal cerebro/placental ratios showed significant correlations to TNF-alpha and IL-6 levels. Conclusion: The present results suggest a strong correlation between levels of TNF-a and IL-6 not only for signs of fetal brain sparing, but also for uteroplacental blood flow. This finding supports the role of tissue injury in cases of fetal brain sparing, but whether this is a reflection of brain damage or secondary to placental pathology needs further evaluation

Wpływ ekstraktu z Camellia sinensis na poziom ekspresji czynników transkrypcyjnych i genów cytochromu P450 kodujących enzymy I fazy metabolizmu leków

Green tea (Camellia sinensis) is widely used as a popular beverage and dietary supplement that can significantly reduce the risk of many diseases. Despite the widespread use of green tea, the data regarding the safety as well as herb-drug interactions are limited. Therefore, the aim of our study was to assess the influence of standardized green tea extract (GTE) containing 61% catechins and 0.1% caffeine on the expression level of rat CYP genes and the corresponding transcription factors expression by realtime PCR. The findings showed that GTE resulted in a significant decrease of CYP2C6 expression level by 68% (p<0.001). In case of CYP3A1 and CYP3A2, the mRNA levels were also reduced by extract but in a lesser degree compared to CYP2C6. Simultaneously the significant increase in the mRNA level of CAR, RXR and GR factors was observed by 54% (p<0.05), 79% (p<0.001) and 23% (p<0.05), respectively after 10 days of green tea extract administration. In addition, there was noted a small increase of CYP1A1 expression level by 21% (p>0.05) was noted. No statistically significant differences were observed for CYP1A2 and CYP2D1/2. In the same study we observed an increase in amount of ARNT gene transcript by 27% (p<0.05) in the long-term use. However, green tea extract showed the ability to stimulate HNF-1α both after 3 and 10 days of treatment by 30% (p<0.05) and 80% (p<0.001), respectively. In contrast, no change was observed in the concentration of HNF-4α cDNA. These results suggest that GTE may change the expression of CYP enzymes, especially CYP2C6 (homologue to human CYP2C9) and may participate in clinically significant interactions with drugs metabolized by these enzymes.Zielona herbata (Camellia sinensis) jest powszechnie stosowana jako napój i suplement diety i może istotnie zmniejszać ryzyko wystąpienia wielu chorób. Pomimo powszechnego 59 Effect of Camellia sinensis extract on the expression level of transcription factors and cytochrome P450 genes coding... Vol. 59 No. 4 2013 zastosowania zielonej herbaty, dane dotyczące bezpieczeństwa jak i interakcji preparatu roślinnego i leku syntetycznego są bardzo ograniczone. Celem badania była ocena wpływu standaryzowanego ekstraktu z zielonej herbaty (GTE) zawierającego 61% katechin i 0,1% kofeiny na poziom ekspresji szczurzych genów CYP i czynników transkrypcyjnych stosując technikę real-time PCR. Wyniki wykazały, że GTE znacznie obniża poziom ekspresji CYP2C6 o 68% (p<0,001). W przypadku CYP3A1 i CYP3A2 poziom mRNA tych genów był również redukowany przez ekstrakt, ale w mniejszym stopniu w porównaniu do CYP2C6. Istotny wzrost w poziomie mRNA obserwowano dla czynników CAR, RXR i GR odpowiednio o 54% (p<0,05), 79% (p<0,001) i 23% (p<0,05) po 10 dniach stosowania ekstraktu. Dodatkowo, zanotowano niewielki wzrost poziomu ekspresji CYP1A1 o 21% (p>0,05). Brak istotnych różnic zaobserwowano dla CYP1A2 i CYP2D1/2. W badaniu wykazano również wzrost ilości transkryptu genu ARNT o 27% (p<0,05) podczas dłuższego stosowania. Ponadto, ekstrakt z zielonej herbaty wykazał zdolność do stymulacji HNF-1α zarówno po 3, jak i 10 dniach trwania eksperymentu odpowiednio o 30% (p<0,05) i 80% (p<0,001). Brak zmian obserwowano w przypadku stężenia cDNA dla HNF-4α. Wyniki te sugerują, że GTE może zmieniać ekspresję enzymów CYP, szczególnie w przypadku CYP2C6 (homolog ludzki CYP2C9) i może uczestniczyć w klinicznie istotnych reakcjach z lekami metabolizowanymi przez te enzymy

In vitro and in vivo activities of flavonoids - apigenin, baicalin, chrysin, scutellarin - in regulation of hypertension - a review for their possible effects in pregnancy-induced hypertension

Flavonoids and their conjugates are the most important group of natural chemical compounds in drug discovery and development. The search for pharmacological activity and new mechanisms of activity of these chemical compounds, which may inhibit mediators of inflammation and influence the structure and function of endothelial cells, can be an interesting pharmacological strategy for the prevention and adjunctive treatments of hypertension, especially induced by pregnancy. Because cardiovascular diseases have multifactorial pathogenesis these natural chemical compounds with wide spectrum of biological activities are the most interesting source of new drugs. Extracts from one of the most popular plant used in Traditional Chinese Medicine, Scutellaria baicalensis Georgi could be a very interesting source of flavonoids because of its exact content in quercetin, apigenin, chrysin and scutellarin as well as in baicalin. These flavonoids exert vasoprotective properties and many activities such as: anti-oxidative via several pathways, anti-inflammatory, anti-ischaemic, cardioprotective and anti-hypertensive. However, there is lack of summaries of results of studies in context of potential and future application of flavonoids with determined composition and activity. Our review aims to provide a literature survey of in vitro, in vivo and ex vivo pharmacological studies of selected flavonoids (apigenin, chrysin and scutellarin, baicalin) in various models of hypertension carried out in 2008–2018