Receptor for advanced glycation end products (RAGE) and glyoxalase I gene polymorphisms in pathological pregnancy

Changes in circulating levels of carboxymethyllysine, soluble receptor for advanced glycation end products (sRAGE), and inflammation markers in women during normal pregnancy

Objective: To determine the circulating levels of insulin, Nε-carboxymethyllysine (CML), soluble receptor for advanced glycation end products (sRAGE), and markers of inflammation and oxidative stress (OS) in maternal and umbilical cord blood in a cohort of healthy women with normal pregnancy.Methods: We conducted an observational longitudinal study in a group of women (n = 31; age range 18-39 years) with healthy pregnancy starting at 30 weeks of gestation and finishing at the time of delivery. We collected weight and height in the participants and their neonates and calculated body mass index (BMI). Blood from each patient was collected at 30th week of pregnancy and at delivery when a sample of cord blood was also obtained. Glucose, lipid profile, CML, sRAGE, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), highly sensitivity C-reactive protein (hsPCR), and insulin were determined. The study was approved by the University of Guanajuato Institutional Ethics Committee.Results: All pregnancies reached term (mean gestational time 38.9 ± 0.83 weeks) and there were no maternal complications. Mean age was 27.6 years. Lipid profile values were higher in the group compared with our values in nonpregnant women. During pregnancy, levels of insulin increased (p < .0006), CML (p < .0001) and sRAGE (p < .01) decreased, levels of MDA did not change, while those of TNF-α and hsPCR tended to increase. In the neonates, we found lower levels of CML (p < .003), hsPCR (p < .004), and insulin (p < .004) and higher levels of sRAGE (p < .013) and TNF-α (p < .022) compared to their mothers at delivery. In the total group, we found association of CML of the mother at baseline with the CML (p < .0006) and MDA (p < .002) in neonates, while maternal sRAGE at the end of pregnancy was associated with CML (p < .004) of their neonates.Conclusions: Our study confirms that normal pregnancy is accompanied by insulin resistance (IR) and significant increase in lipid profile, and demonstrates that circulating levels of CML and sRAGE decreased significantly at the end of pregnancy. The lack of association between the course of insulin levels and those of CML probably results from the predominant role of placental factors in the pathogenesis of IR in pregnancy. sRAGE levels in the neonates are markedly increased compared to their mothers suggesting a placental origin of this compound which may have a protective effect on the fetus since sRAGE restricts Advanced glycation end product (AGE) effects and may exert anti-inflammatory effects.

Diagnostic Potential of Evaluation of SDF-1α and sRAGE Levels in Threatened Premature Labor

Preterm birth remains the most prevalent cause of neonatal morbidity. This study aimed to evaluate the diagnostic value of SDF-1α, resistin, secretory RAGE (sRAGE), and endogenous secretory RAGE (esRAGE) in preterm labor. A total of 211 pregnant women participated in the study. Group A contained 72 women between 22 and 36 weeks of gestation, with premature labor, who finally had preterm birth. Group B contained 66 women in labor between 37 and 41 weeks of gestation. Women in group A had lower SDF-1α and sRAGE levels than those in group B. Moreover, in group A, SDF-1α and sRAGE levels were correlated with the latency period from the occurrence of premature labor symptoms until delivery. Sensitivity and specificity of studied parameters for prediction of preterm birth were 95% and 40% for SDF-1α and 51.3% and 93.5% for sRAGE, respectively. The prognostic value of plasma SDF-1α and sRAGE levels was comparable with that of cervical length ultrasound measurement and serum C-reactive protein levels. We conclude that SDF-1α and sRAGE appear to play a major role in the diagnosis of preterm birth and its evaluation could be convenient and useful for predicting preterm birth.

The pathophysiology of intrahepatic cholestasis of pregnancy

A number of liver disorders are specific to pregnancy. Amongst these, intrahepatic cholestasis of pregnancy (ICP), also known as obstetric cholestasis (OC), is the commonest, affecting approximately 1 in 140 UK pregnancies. Patients commonly present in the third trimester with severe pruritus and deranged serum liver tests; bile acids are elevated, in severe cases >40 μmol/L. Although the disease is considered relatively benign for the mother, increased rates of adverse fetal outcomes, including stillbirth, are associated with ICP. As our knowledge of the mechanisms underlying bile acid homeostasis has advanced in the last 15 years our understanding of ICP has grown, in particular with respect to genetic influences on susceptibility to the disease, the role of reproductive hormones and their metabolites and the possible identity of the pruritic agents. In this review, we will describe recent advances in the understanding of this condition with a particular emphasis on how aspects of genetic and reproductive hormone involvement in pathophysiology have been elucidated. We also review recent developments regarding our knowledge of placental and fetal pathophysiology and the long-term health consequences for the mother and child.

Soluble RAGE and the RAGE ligands HMGB1 and S100A12 in critical illness: impact of glycemic control with insulin and relation with clinical outcome

Systemic inflammation often leads to complications in critically ill patients. Activation of the receptor for advanced glycation end-products (RAGE) generates inflammatory cytokines, proteases, and oxidative stress and may link inflammation to subsequent organ damage. Furthermore, hyperglycemia-induced oxidative stress increases RAGE ligands and RAGE expression. We hypothesized that preventing hyperglycemia during critical illness reduces the risk of excessively enhanced RAGE signaling, which could relate to clinical outcomes and risk of death. In 405 long-stay surgical intensive care unit patients randomized to intensive or conventional insulin treatment, serum concentrations of soluble RAGE (decoy receptor) and the RAGE ligands high-mobility group box 1 (HMGB1) and S100A12 were measured on admission, day 7, and last day. These were compared with levels in 71 matched control subjects and with C-reactive protein (CRP) as a routinely monitored inflammation marker. On admission, soluble RAGE, HMGB1, S100A12, and CRP were higher in patients than in controls. The HMGB1, S100A12, and CRP remained elevated throughout intensive care unit stay, whereas soluble RAGE decreased to levels lower than in controls by day 7. Unexpectedly, insulin treatment did not affect the circulating levels of these markers. In univariable analysis, elevated levels of soluble RAGE on admission were associated with adverse outcome, including circulatory failure, kidney failure, liver dysfunction, and mortality. The associations with circulatory and kidney failure remained significant in multivariable logistic regression analysis corrected for baseline risk factors. Critical illness affects components of RAGE signaling, unaffected by insulin treatment. Elevated on-admission soluble RAGE was associated with adverse outcomes.

Soluble and Endogenous Secretory Receptors for Advanced Glycation End Products in Threatened Preterm Labor and Preterm Premature Rupture of Fetal Membranes

The aim of the study was to compare sRAGE and esRAGE plasma levels in pregnant women with (A) threatened premature labor (n = 41), (B) preterm premature rupture of membranes (n = 49), and (C) preterm rupture of membranes at term (n = 48). The relationship between these and classic intrauterine infection markers and the latent time from symptoms up to delivery depending on RAGE's concentration were investigated. In groups A and B, a positive correlation was found between plasma sRAGE and latent time (r = 0,422; p = 0,001; r = 0,413, p = 0,004, resp.). High prognostic values were found in both groups for plasma sRAGE concentration and the latent time from symptoms up to delivery. Groups B and C presented higher levels of esRAGE than group A (526,315 ± 129,453 pg/mL and 576,212 ± 136,237 pg/mL versus 485,918 ± 133,127 pg/mL, p< 0,05). The conclusion is that sRAGE concentration can be a favorable prognostic factor in the presence of symptoms of threatened premature labor. Higher esRAGE plasma level in case of the rupture of membranes in mature and premature pregnancy suggests its participation in fetal membranes destruction.

Soluble receptors for advanced glycation end products and receptor activator of NF-κB ligand serum levels as markers of premature labor

Background

This study aimed to determine the relationships between secretory and endogenous secretory receptors for advanced glycation end products (sRAGE, esRAGE), sRANKL, osteoprotegerin and the interval from diagnosis of threatened premature labor or premature rupture of the fetal membranes to delivery, and to evaluate the prognostic values of the assessed parameters for preterm birth.

Methods

Ninety women between 22 and 36 weeks’ gestation were included and divided into two groups: group A comprised 41 women at 22 to 36 weeks’ gestation who were suffering from threatened premature labor; and group B comprised 49 women at 22 to 36 weeks’ gestation with preterm premature rupture of the membranes. Levels of sRAGE, esRAGE, sRANKL, and osteoprotegerin were measured. The Mann–Whitney test was used to assess differences in parameters between the groups. For statistical analysis of relationships, correlation coefficients were estimated using Spearman’s test. Receiver operating characteristics were used to determine the cut-off point and predictive values.

Results

In group A, sRAGE and sRANKL levels were correlated with the latent time from symptoms until delivery (r = 0.422; r = −0.341, respectively). The sensitivities of sRANKL and sRAGE levels for predicting preterm delivery were 0.895 and 0.929 with a negative predictive value (NPV) of 0.857 and 0.929, respectively. In group B, sRAGE and sRANKL levels were correlated with the latent time from pPROM until delivery (r = 0.381; r = −0.439). The sensitivity of sRANKL and sRAGE for predicting delivery within 24 h after pPROM was 0.682 and 0.318, with NPVs of 0.741 and 0.625, respectively. Levels of esRAGE and sRANKL were lower in group A than in group B (median = 490.2 vs 541.1 pg/mL; median = 6425.0 vs 11362.5 pg/mL, respectively).

Conclusions

Correlations between sRAGE, sRANKL, and pregnancy duration after the onset of symptoms suggest their role in preterm delivery. The high prognostic values of these biomarkers indicate their usefulness in diagnosis of pregnancies with threatened premature labor.

Elevation of soluble form of receptor for advanced glycation end products (sRAGE) in recurrent pregnancy losses (RPL): possible participation of RAGE in RPL

OBJECTIVE

To determine whether the soluble receptor for advanced glycation end products (sRAGE) and immune inflammatory markers are associated with recurrent pregnancy losses (RPL).

DESIGN

Prospective case-control study.

SETTING

University clinic.

PATIENT(S)

A total of 93 women (age 35.8±4.6 years) were enrolled including 63 women with three or more recurrent pregnancy losses (RPL), and age-matched fertile controls with a history of at least one live birth and no history of pregnancy losses (n=30).

INTERVENTION(S)

Peripheral blood collection.

MAIN OUTCOME MEASURE(S)

Assessment of anthropometric, metabolic, and inflammatory immune variables.

RESULT(S)

Levels of sRAGE were statistically significantly higher in RPL patients than in control patients (1,528.9±704.5 vs. 1,149.9±447.4 pg/mL). In the multivariate analysis, the levels of insulin, plasminogen activator inhibitor-1, the resistance index of the uterine radial artery, and the ratio of tumor necrosis factor-α/interleukin-10 producing T helper cells were statistically significantly associated with the serum sRAGE level.

CONCLUSION(S)

Elevated levels of serum sRAGE are associated with RPL. The soluble receptor for advanced glycation end products might contribute to RPL by reducing uterine blood flow and subsequently causing ischemia in the fetus via inflammatory and thrombotic reactions.