Impaired vascular reactivity in pregnant women with insulin-dependent diabetes mellitus

Thrombin/PAR-1 activation induces endothelial damages via NLRP1 inflammasome in gestational diabetes

Gestational diabetes mellitus (GDM) is associated with an increased risk of progressing to type 2 DM and cardiovascular disease; however, the pathogenesis is still poorly understood. This study was to investigate roles of thrombin and its receptor protease-activated receptor 1 (PAR-1) and NLRP1 inflammasome in endothelial injury in GDM condition. Umbilical cord and plasma of GDM patients and high glucose (HG) cultured human umbilical vein endothelial cells (HUVECs) were used to examine the pathological changes of these pathways. Meanwhile, ameliorative effects and potential mechanisms of a natural product sarsasapogenin (Sar) were investigated in HUVECs. Thrombin/PAR-1 pathway, advanced glycation endproducts (AGEs) and their receptor (RAGE) axis, and the nucleotide-binding domain and leucine-rich repeat containing protein 1 (NLRP1) inflammasome were activated in GDM condition and HG-cultured HUVECs, accompanied by endothelial injury (decreased cell viability and increased lactate dehydrogenase release). Nevertheless, thrombin inhibition or PAR-1 antagonism caused decreases in AGEs formation and RAGE expression in HG-cultured HUVECs, while AGEs inhibition or RAGE antagonism declined PAR-1 expression not thrombin activity. Furthermore, thrombin inhibition or PAR-1 antagonism restrained NLRP1 inflammasome activation in HG-cultured HUVECs; meanwhile, NLRP1 expression and interleukin 18 levels were remarkably reduced in HG-cultured HUVECs after PAR-1 knockdown. Interestingly, Sar co-treatment could suppress thrombin/PAR-1 pathway, NLRP1 inflammasome, and AGEs/RAGE axis. Together, endothelial damages in GDM were likely due to enhanced interaction between AGEs/RAGE axis and thrombin/PAR-1 pathway, followed by NLRP1 inflammasome activation. Moreover, Sar may act as a protective agent against endothelial injury in chronic HG condition.

Methylation profile of genes involved in inflammation, in the blood from pregnancies with maternal preeclampsia due to untreated gestational diabetes mellitus

PURPOSE

To investigate DNA methylation changes in peripheral blood from patients with gestational diabetes mellitus (GDM) and preeclampsia (PE) due to poorly treated GDM.

METHODS

Eighteen pregnant women participated in the study: 6 with GDM, 6 with PE, and 6 healthy controls. The promoter methylation status of genes was profiled using the Human Inflammatory Response and Autoimmunity EpiTect Methyl II Signature PCR Array profiles. The results were validated with quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Fewer inflammation-related genes were significantly hypomethylated in PE cases compared to healthy subjects than in GDM cases. Some of the examined genes show different methylation patterns between GDM and PE.

CONCLUSIONS

The epigenetic changes observed in this study indicate that GDM and PE exhibit specific DNA methylation profiles, with possible clinical applications.

Mechanisms and Clinical Significance of Endothelial Dysfunction in High-Risk Pregnancies

The maternal cardiovascular system undergoes critical anatomic and functional adaptations to achieve a successful pregnancy outcome which, if disrupted, can result in complications that significantly affect maternal and fetal health. Complications that involve the maternal cardiovascular system are among the most common disorders of pregnancy, including gestational hypertension, preeclampsia, gestational diabetes, and impaired fetal growth. As a central feature, maternal endothelial dysfunction is hypothesized to play a predominant role in mediating the pathogenesis of these high-risk pregnancies, and as such, might proceed and precipitate the clinical presentation of these pregnancy disorders. Improving or normalizing maternal endothelial function in high-risk pregnancies might be an effective therapeutic strategy to ameliorate maternal and fetal clinical outcomes.

Experimental gestational diabetes mellitus induces blunted vasoconstriction and functional changes in the rat aorta

Diabetic conditions increase vascular reactivity to angiotensin II in several studies but there are scarce reports on cardiovascular effects of hypercaloric diet (HD) induced gestational diabetes mellitus (GDM), so the objective of this work was to determine the effects of HD induced GDM on vascular responses. Angiotensin II as well as phenylephrine induced vascular contraction was tested in isolated aorta rings with and without endothelium from rats fed for 7 weeks (4 before and 3 weeks during pregnancy) with standard (SD) or hypercaloric (HD) diet. Also, protein expression of AT₁R, AT₂R, COX-1, COX-2, NOS-1, and NOS-3 and plasma glucose, insulin, and angiotensin II levels were measured. GDM impaired vasoconstrictor response (P < 0.05 versus SD) in intact (e+) but not in endothelium-free (e−) vessels. Losartan reduced GDM but not SD e− vasoconstriction (P < 0.01 versus SD). AT₁R, AT₂R, and COX-1 and COX-2 protein expression were significantly increased in GDM vessels (P < 0.05 versus SD). Results suggest an increased participation of endothelium vasodilator mediators, probably prostaglandins, as well as of AT₂ vasodilator receptors as a compensatory mechanism for vasoconstrictor changes generated by experimental GDM. Considering the short term of rat pregnancy findings can reflect early stage GDM adaptations.

Assessment of endothelial function in pregnant women with preeclampsia and gestational diabetes mellitus by flow-mediated dilation of brachial artery

PURPOSE

To compare endothelial function, as assessed by flow-mediated dilation (FMD) in pregnant women with preeclampsia (PE), gestational diabetes mellitus (GDM) and healthy pregnant women.

METHODS

We conducted a cross-sectional study of eighty women who were selected and divided into three groups: Group A comprising 42 pregnant women with PE, Group B (control) consisting of 19 normotensive pregnant women with no comorbidities and Group C consisting of 19 pregnant women with GDM. The women underwent FMD and the results were compared between groups. The data were obtained from the Center for Fetal Medicine, Hospital das Clínicas, Federal University of Minas Gerais, Brazil (CEMEFE-HC-UFMG) after approval by the Ethics and Research Committee on June 4, 2008 under no CAAE-0280.0.203.000-08.

RESULTS

Nonparametric variance analysis showed no statistically significant difference between the characteristics of the three groups. The comparison between the results of the mean values of brachial artery FMD groups of pregnant women with preeclampsia (FMD = 5.36 ± 4.61 %), gestational diabetes (FMD = 9,18 ± 5.98 %) and pregnant women in the control group (FMD = 17.55 ± 8.35 %) showed that a statistically significant difference was found between groups using the Dunn test. The comparison between groups PE × GDM was not statistically significant. The group consisting of pregnant women with GDM associated with those with PE had significantly lower results for FMD (6.55 ± 5.33 %) than the control group (17.55 ± 8.35 %, p = 0.00).

CONCLUSIONS

The group consisting of pregnant women with GDM or PE showed results for FMD significantly lower than the control group, suggesting possible endothelial injury in these patients.

Endothelial dysfunction in myometrial arteries of women with gestational diabetes

AIMS

This study directly examined endothelial function of myometrial arteries in the uterus of women with gestational diabetes mellitus (GDM), healthy pregnant and non-pregnant women. It also examined whether endothelial function was affected by the changes in glucose concentration (from 2 to 12mmol/L) that is seen in poorly controlled diabetes.

METHODS

Ex vivo myometrial arteries from the uterus of women with GDM (N=16) as well as healthy pregnant (N=16) and non-pregnant women (N=15) were mounted on a wire myograph. The effect of changing glucose concentrations from 5mmol/L to 2, 8 and 12mmol/L glucose for 30min was studied.

RESULTS

Myometrial arteries from women with GDM had significantly impaired endothelium-dependent relaxation compared to those from both healthy pregnant and non-pregnant women (two-way ANOVA, p<0.001). Changes in glucose concentration had no effect on constriction or endothelium-dependent relaxation in any group studied (two-way ANOVA, p>0.05).

CONCLUSIONS

Fluctuations of glucose concentrations between 2 and 12mmol/L do not affect endothelial function. Endothelial dysfunction is present in the myometrial arteries of women with GDM, an inherent defect which may be responsible for some of the complications of GDM.

Uterine artery function in a mouse model of pregnancy complicated by diabetes

It has been demonstrated previously that endothelium-dependent vasodilatation is impaired in myometrial arteries from women with gestational diabetes, which may play a role in mediating complications observed in diabetic pregnancies. It is not known which aspects of endothelium-dependent vasodilatation are impaired, thus a mouse model of pregnancy complicated by streptozotocin-induced diabetes was established to investigate underlying mechanisms. Uterine arteries from term-pregnant, diabetic and control C57Bl6/J mice were assessed using acetylcholine (ACh; 10(-10)-10(-5)M) in the presence or absence of a nitric oxide (NO) synthase inhibitor (L-NNA; 10(-5)M), a cyclooxygenase (COX) inhibitor (indomethacin; 10(-5)M) or the two in combination. Sensitivity to ACh was comparable between diabetic and control mice. However, the contribution of endothelium-dependent vasodilators was significantly altered. L-NNA significantly inhibited the relaxation of arteries from diabetic compared to control mice (65+/-11% vs 18+/-6%; p<.05). L-NNA and indomethacin significantly inhibited the relaxation of arteries from diabetic mice compared to control (87+/-5% vs 33+/-14%; p<0.05). These data indicate that endothelium-dependent relaxation of the uterine artery of control, pregnant mice was largely mediated by the non-NO/non-COX component. Surprisingly, arteries from diabetic mice were primarily dependent on NO, which may affect compensatory capacity as the disease progresses.

Vascular Reactivity in Preeclampsia Assessed Noninvasively Using Maternal Brachial Artery Hyperemic Response

OBJECTIVE

To estimate if women with preeclampsia had measurable differences in the brachial artery waveforms after blood flow occlusion.

METHODS

In a cross-sectional study, 14 preeclamptic and 28 matched normotensive women were assessed. Hemolysis, elevated liver enzymes, low platelets syndrome patients were excluded. All patients had baseline brachial Doppler flow velocities while resting in the left lateral position and after a 60-second forearm occlusion. Doppler waveforms were analyzed from the brachial artery 30-45 seconds after the release of the blood pressure cuff. We analyzed the classical Doppler waveform parameters of systolic diastolic, mean velocity and pulsatility index, time taken to achieve peak systolic velocity, systolic acceleration time, the percentage of time in each cycle to achieve peak systolic velocity, and systolic acceleration from 3 waveforms. Comparison of the percentage change in each of these parameters between the groups was done using t tests.

RESULTS

Before brachial artery occlusion, systolic acceleration time was significantly less in the preeclamptic group (77.5 +/- 14.4 milliseconds versus 93.2 +/- 11.7 milliseconds; (P < .001). After occlusion, the percentage change in the systolic acceleration and systolic acceleration time was increased in the normotensive group (P < .001).

CONCLUSION

There was significantly increased impedance to blood flow downstream assessed by Doppler waveform analysis after a period of forearm ischemia (blood pressure occlusion) in the women with preeclampsia.

LEVEL OF EVIDENCE

II-1.