FAS A-670G and Fas ligand IVS2nt A 124G polymorphisms are significantly increased in women with pre-eclampsia and may contribute to HELLP syndrome: a case-controlled study.

OBJECTIVE: We evaluated the association between the Fas-670A/G and the Fas ligand FasL IVS2nt 124 A/G polymorphisms and the risk of pre-eclampsia and its complications. DESIGN: A case-controlled study. SETTING: University Hospitals in most areas of Tunisia. POPULATION: We recruited 300 pregnant women who developed pre-eclampsia and 300 age-matched healthy pregnant women from the same hospital. METHODS: Genotyping of Fas-670A/G and the FasL IVS2nt 124A/G gene polymorphisms were conducted using polymerase chain reaction-restriction fragment length polymorphism among our cohort. MAIN OUTCOME MEASURES: Fisher's exact test was used to compare the statistical differences between groups for categorical variables and Student t tests were used for continuous variables. RESULTS: The frequency of the Fas-670G gene variant was significantly increased in women with pre-eclampsia (42%) compared with control women (30%; P < 0.001). Also, a statistically significant difference was obtained in the distribution of the FasL IVS2nt 124G gene variant when comparing women with pre-eclampsia (43%) with controls (30%; P < 0.001). Interestingly, we found that the carriage of Fas-670G was associated with increased liver enzymes, suggesting an increased prevalence of the haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome, a pre-eclampsia complication. CONCLUSION: The Fas-670G and FasL IVS2nt 124G polymorphisms are associated with a higher risk of pre-eclampsia and its complications. TWEETABLE ABSTRACT: Polymorphisms in the Fas and FasL genes are associated with increased risk of pre-eclampsia and HELLP syndrome.

Interleukin-10 rs1800871 (-819C/T) and ATA haplotype are associated with preeclampsia in a Tunisian population.

OBJECTIVES: Interleukin-10 (IL-10) is implicated in several aspects of pregnancy. As genetic predisposition can be involved in the development of preeclampsia, the association between IL-10's promoter region polymorphisms and this pathology has been investigated, although with conflicting results. To date, only a small cohort study (total n = 40) has evaluated this association in the African continent, and none have been conducted in Tunisia. Hence, we evaluated the association between these polymorphisms and the risk of preeclampsia in a large Tunisian cohort. STUDY DESIGN: 345 preeclampsia patients and 300 controls were genotyped for the IL-10 promoter region variants -1082A/G, -819C/T and -592A/C using real-time PCR. MAIN OUTCOME MEASURES: Differences in means were determined by Student's t-test, while intergroup significance was assessed by Pearson χ2 or 2-way ANOVA. Genotypes were tested for Hardy-Weinberg equilibrium (HWE) in the control and cases. Logistic regression analysis was performed in order to determine the odds ratios and 95% confidence intervals associated with the linkage disequilibrium risk. RESULTS: An increased frequency of the -819 T (minor) allele and the -819 T/T genotype was seen in preeclampsia cases. Also, three-locus haplotype (-1082AG/-819CT/-592AC) analysis identified the ATA haplotype as having a higher incidence in women with preeclampsia (OR = 1.48, 95% CI: 1.03-2.11) and this was confirmed by multivariate regression analysis (OR = 1.65, 95% CI: 1.13-2.43) after controlling for covariates. CONCLUSIONS: We suggest that the IL-10 -819 T/T variant and the ATA haplotype, which are associated with low production of IL 10, represent genetic risk factors for preeclampsia in Tunisian women.

Molecular insights into the normal operation, regulation, and multisystemic roles of K+-Cl- cotransporter 3 (KCC3).

Long before the molecular identity of the Na+-dependent K+-Cl- cotransporters was uncovered in the mid-nineties, a Na+-independent K+-Cl- cotransport system was also known to exist. It was initially observed in sheep and goat red blood cells where it was shown to be ouabain-insensitive and to increase in the presence of N-ethylmaleimide (NEM). After it was established between the early and mid-nineties, the expressed sequence tag (EST) databank was found to include a sequence that was highly homologous to those of the Na+-dependent K+-Cl- cotransporters. This sequence was eventually found to code for the Na+-independent K+-Cl- cotransport function that was described in red blood cells several years before. It was termed KCC1 and led to the discovery of three isoforms called KCC2, KCC3, and KCC4. Since then, it has become obvious that each one of these isoforms exhibits unique patterns of distribution and fulfills distinct physiological roles. Among them, KCC3 has been the subject of great attention in view of its important role in the nervous system and its association with a rare hereditary sensorimotor neuropathy (called Andermann syndrome) that affects many individuals in Quebec province (Canada). It was also found to play important roles in the cardiovascular system, the organ of Corti, and circulating blood cells. As will be seen in this review, however, there are still a number of uncertainties regarding the transport properties, structural organization, and regulation of KCC3. The same is true regarding the mechanisms by which KCC3 accomplishes its numerous functions in animal cells.

OS060. Exercise training promotes placental growth and development in an animal model of preeclampsia superimposed on chronic hypertension.

INTRODUCTION: Chronic hypertension is an important risk factor for preeclampsia, increasing the prevalence of the disease to 15-25% in pregnant women. Unfortunately there are no known treatments for this disease aside from inducing delivery of the fetus. Nonetheless, several studies have found exercise training to have a protective effect on the risk of developing preeclampsia. OBJECTIVES: To determine the mechanisms implicated in the preventive effect of exercise training on preeclampsia, by focusing on the placenta. METHODS: Double transgenic mice, overexpressing both human renin and angiotensinogen (R(+)/A(+)), were used to investigate the effect of exercise training on an animal model of preeclampsia superimposed on chronic hypertension. Mice were placed in cages with free access to an exercise wheel 4 weeks prior to and during pregnancy. At gestational day 18, mice were sacrificed and their organs were collected. Real time PCR and Western Blot were performed to evaluate placental genes and proteins, respectively. Circulating sFlt-1(soluble Fms-like tyrosine kinase-1) levels were investigated by ELISA. Placental alterations were assessed by histology and immunohistochemistry, while blood pressure was measured by radiotelemetry. RESULTS: Sedentary R(+)/A(+) mice presented with significantly greater placental pathology, which was normalized with exercise training. This was characterized by a normalization of cytokeratin and histone H3 protein expression, thereby restoring placental development, specifically looking at trophoblasts and trophoblast giant cells, respectively. This exercise training effect appears to normalize placental growth primarily by promoting angiogenesis and development. Indeed, a pro-angiogenic shift could be detected which was characterized by an increase in placental growth factor gene expression, along with a decrease in sFlt-1 gene expression, which produced a decrease in circulating sFlt-1. Sedentary R(+)/A(+) mice also presented with a significant increase in VEGF protein, which was significantly decreased with exercise. Of interest, since it has been observed to be decreased with preeclampsia, insulin regulated aminopeptidase (IRAP) gene expression was significantly increased in the trained transgenic mice. Finally, exercise training prevented the increase in blood pressure normally observed at the end of gestation in sedentary R(+)A(+) mice. CONCLUSION: Exercise training both before and during gestation appears to promote placental growth and development by producing a pro-angiogenic placental environment. Put together, along with the lack in blood pressure increase, these factors may be responsible for preventing the development of preeclampsia in our animal model of preeclampsia superimposed on chronic hypertension. Identifying the mechanisms implicated in exercise-induced preeclampsia risk reduction will be critical to improve preeclampsia prophylaxis.

Transgenic mice for studies of the renin-angiotensin system in hypertension.

Hypertension is a polygenic and multi-factorial disorder that is extremely prevalent in western societies, and thus has received a great deal of attention by the research community. The renin-angiotensin system has a strong impact on the control of blood pressure both in the short- and long-term, making it one of the most extensively studied physiological systems. Nevertheless, despite decades of research, the specific mechanisms implicated in its action on blood pressure and electrolyte balance, as well as its integration with other cardiovascular pathways remains incomplete. The production of transgenic models either over-expressing or knocking-out specific components of the renin-angiotensin system has given us a better understanding of its role in the pathogenesis of hypertension. Moreover, our attention has recently been refocused on local tissue renin-angiotensin systems and their physiological effect on blood pressure and end-organ damage. Herein, we will review studies using genetic manipulation of animals to determine the role of the endocrine and tissue renin-angiotensin system in hypertension. We will also discuss some untraditional approaches to target the renin-angiotensin system in the kidney.

Bradykinin facilitates noradrenaline spillover during contraction in the canine gracilis muscle.

Noradrenaline spillover from skeletal muscle vascular areas increases during exercise but the underlying mechanisms are not well understood. Muscle contraction itself causes changes in many factors that could affect noradrenaline spillover. For instance, it has been reported that bradykinin is synthesized in skeletal muscle areas during contraction. Because the B2 bradykinin receptor facilitates noradrenaline spillover, it may be involved in the increase associated with contraction. In this experiment, we studied the effect of bradykinin on noradrenaline spillover in the in situ canine gracilis muscle, using the specific B2 antagonist HOE 140. The drug did not modify noradrenaline spillover at rest, but did cause a significant decrease during muscle contraction, from 558 to 181 pg min(-1). As reported previously in the literature, fractional extraction of noradrenaline decreased during muscle contraction. This effect was independent of HOE 140 treatment. In light of our results, it seems that bradykinin formation during muscle contraction may play an important part in the observed increase in noradrenaline spillover but does not affect fractional extraction.

Effect of blood flow and muscle contraction on noradrenaline spillover in the canine gracilis muscle.

Many authors have reported that, during exercise, noradrenaline spillover increases and fractional extraction decreases. It has been suggested that the increase in blood flow to active muscles may contribute to these effects. Muscle contraction also causes changes in many factors that may affect noradrenaline spillover and fractional extraction. In this experiment, we studied the effect of muscle contraction and blood flow on noradrenaline and adrenaline spillover and fractional extraction in the in situ canine gracilis muscle. The low intensity stimulation protocol enabled us to have muscle contractions without any effect on the local concentration of noradrenaline, as measured by microdialysis, and noradrenaline spillover. Fractional extraction of both noradrenaline and adrenaline was unaffected by increasing blood flow three and four times its resting value. In addition, noradrenaline spillover was increased by the higher blood flow, from 188 to 452 pg x min(-1) at rest and from 246 to 880 pg x min(-1) during stimulation. Stimulation of muscle contraction caused a significant increase in fractional extraction of noradrenaline and a nonsignificant increase in adrenaline extraction. In addition, an adrenaline spillover was observed in certain conditions. In light of our results, it seems that blood flow may not be the main factor decreasing fractional extraction of noradrenaline during exercise. However, blood flow could contribute to the increase in noradrenaline spillover observed in the active muscles during exercise.