Composition and interaction of maternal microbiota with immune mediators during pregnancy and their outcome: A narrative review

The connection between maternal microbiota and infant health has been greatly garnered interest for therapeutic purposes. The early resident microbiota perpetually exhibits much more flexibility as compared to that of the adults, and therefore, constant need of understanding the infant as well as maternal microbiota and their implications however has increased. In this review, we focus mainly on the diversity of overall maternal microbiota including the gut, vaginal, colostrum microbiota and how inflammatory markers fluctuate throughout the normal pregnancy as well in pregnancy with complications. The maternal body undergoes a cascade of physiological changes including hormonal, immunological and metabolic events to support the fetal development. These changes at the time of pregnancy have been correlated with alteration in the composition and diversity of maternal microbiota. Along with alteration in microbiome, the levels of circulatory cytokines fluctuate by complex network of inflammation, in order to prevent the fetal allograft throughout the pregnancy. The dynamic relationship of gut microbiota with the host and its immune system allows one to have greater insights of their role in pregnancy and newborn's health. Emerging evidence suggests that the vertical transmission of bacterial community from mother to newborn may begin in-utero which contributes in developing the immune system and infant gut microbiota.

Evaluation of serum placenta-specific gene 8 protein, total antioxidant capacity, interleukin-10, interleukin-17A, interleukin-21 and interleukin-33 levels in Turkish women with gestational diabetes mellitus

PURPOSE

Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance that begins or is diagnosed during pregnancy. Our study aimed to establish a correlation between proinflammatory and anti-inflammatory response in order to be able to develop treatment strategies and determine early diagnosis biomarkers in the sera of cases diagnosed with GDM. Moreover, we aimed to investigate interleukin (IL), placenta-specific gene 8 protein (PLAC8) and total antioxidant capacity (TAC) in patients with GDM.

METHODS

A total of 121 patients were included in the study. These were divided into four patient groups: pregnant and diagnosed with DM (P-GDM, n=30); pregnant and not diagnosed with DM (P-NGDM, n=32); non-pregnant diagnosed with DM (NP-DM, n=29) and non-pregnant and not diagnosed with DM (NPNDM, n=30). IL-10, IL-17A, IL-21, IL-33, PLAC8 and TAC determinations from patients were evaluated by ELISA (Enzyme-Linked ImmunoSorbent Assay) method.

RESULTS

IL-10 and IL-33 concentrations were found to be significantly higher in P-GDM and NP-DM patient groups compared to P-NGDM and NP-NDM groups (p<0.001). The PLAC8 level in the P-GDM patient group (20.38±5.37) was determined to be significantly higher than in the P-NGDM patient group (3.41±2.17, p<0.001). TAC in the P-NGDM and NP-NDM groups (12.42±2.31 vs. 12.96±3.78, p<0.001) was determined to be significantly higher than in the P-GDM and NP-DM groups (4.8±0.52 vs. 2.21±0.71, p<0.001).

DISCUSSION

The fact that the importance of PLAC8 level and TAC in the diagnosis and follow-up of GDM in pregnancy is demonstrated for the first time in this study shows that it is unique.

Does treatment modality affect measures of arterial stiffness in women with gestational diabetes?

OBJECTIVE

To investigate whether arterial stiffness (AS) differs between healthy women and women with gestational diabetes mellitus (GDM) managed by different treatment modalities.

METHODS

This was a prospective longitudinal cohort study comparing AS in pregnancies complicated by GDM and low-risk controls. AS was assessed by recording aortic pulse-wave velocity (AoPWV), brachial augmentation index (BrAIx) and aortic augmentation index (AoAIx) using the Arteriograph® at four gestational-age windows: 24 + 0 to 27 + 6 weeks (W1); 28 + 0 to 31 + 6 weeks (W2); 32 + 0 to 35 + 6 weeks (W3) and ≥ 36 + 0 weeks (W4). Women with GDM were considered both as a single group and as subgroups stratified by treatment modality. Data were analyzed using a linear mixed model on each AS variable (log-transformed) with group, gestational-age window, maternal age, ethnicity, parity, body mass index, mean arterial pressure and heart rate as fixed effects and individual as a random effect. We compared the group means including relevant contrasts and adjusted the P-values using Bonferroni correction.

RESULTS

The study population comprised 155 low-risk controls and 127 women with GDM, of whom 59 were treated with dietary intervention, 47 were treated with metformin only and 21 were treated with metformin + insulin. The two-way interaction term of study group and gestational age was significant for BrAIx and AoAIx (P < 0.001), but there was no evidence that mean AoPWV was different between the study groups (P = 0.729). Women in the control group demonstrated significantly lower BrAIx and AoAIx compared with the combined GDM group at W1-W3, but not at W4. The mean difference in log-transformed BrAIx was -0.37 (95% CI, -0.52 to -0.22), -0.23 (95% CI, -0.35 to -0.12) and -0.29 (95% CI, -0.40 to -0.18) at W1, W2 and W3, respectively. The mean difference in log-transformed AoAIx was -0.49 (95% CI, -0.69 to -0.30), -0.32 (95% CI, -0.47 to -0.18) and -0.38 (95% CI -0.52 to -0.24) at W1, W2 and W3, respectively. Similarly, women in the control group also demonstrated significantly lower BrAIx and AoAIx compared with each of the GDM treatment subgroups (diet, metformin only and metformin + insulin) at W1-W3. The increase in mean BrAIx and AoAIx seen between W2 and W3 in women with GDM treated with dietary management was attenuated in the metformin-only and metformin + insulin groups. However, the mean differences in BrAIx and AoAIx between these treatment groups were not statistically significant at any gestational-age window.

CONCLUSIONS

Pregnancies complicated by GDM demonstrate significantly higher AS compared with low-risk pregnancies regardless of treatment modality. Our data provide the basis for further investigation into the association of metformin therapy with changes in AS and risk of placenta-mediated diseases. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The Role of Endothelial Dysfunction in the Pathogenesis of Pregnancy-Related Pathological Conditions: A Review

In the recent decades, endothelial dysfunction (ED) has been recognized as a significant contributing factor in the pathogenesis of many pathological conditions. In interaction with atherosclerosis, hypercholesterolemia, and hypertension, ED plays a crucial role in the pathogenesis of coronary artery disease, chronic renal disease, and microvascular complications in diabetes mellitus. Although ED plays a significant role in the pathogenesis of several pregnancy-related disorders such as preeclampsia, HELLP syndrome, fetal growth restriction, and gestational diabetes mellitus, the exact pathogenetic mechanisms are still a matter of debate. The increased prevalence of these entities in patients with preexisting vascular diseases highlights the essential pathological role of the preexisting ED in these patients. The abnormal uteroplacental circulation and the release of soluble factors from the ischemic placenta into the maternal bloodstream are the main causes of the maternal ED underlying the characteristic preeclamptic phenotype. Besides the increased risk for maternal and fetal poor outcomes, the preexisting ED also increases the risk of development of future cardiovascular diseases in these patients. This study aimed to look deeper into the role of ED in the pathogenesis of several pregnancy-related hypertensive and liver diseases. Hopefully, it could contribute to improvement of the awareness, knowledge, and management of these conditions and also to the reduction of the adverse outcomes and additional long-term cardiovascular complications.

The genetic polymorphisms and levels of adipokines and adipocytokines that influence the risk of developing gestational diabetes mellitus in Thai pregnant women

INTRODUCTION

Aberrant immune and inflammatory response is thought to be involved in the pathogenesis of gestational diabetes mellitus (GDM).

OBJECTIVE

To investigate the genetic polymorphisms and levels of adipokines/adipocytokines that influence the risk of developing GDM in Thai women.

RESEARCH DESIGN & METHODS

This case-control recruited 400 pregnant Thai women. A total of 12 gene polymorphisms at ADIPOQ, adipsin, lipocalin-2, PAI-1, resistin, IL-1β, IL-4, IL-17A, TGF-β, IL-10, IL-6, and TNF-α were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay and RNase H2 enzyme-based amplification (rhAmp) SNP assay. Serum levels of adipokines/adipocytokines were evaluated using Luminex assays.

RESULTS

Mean age, weight before and during pregnancy, body mass index before and during pregnancy, blood pressure, gestational age at blood collection, and median 50 g glucose challenge test were significantly higher in GDM women than control. Significantly lower adiponectin and higher IL-4 levels were found in GDM compared to controls (p = 0.001 and p = 0.03, respectively). The genotype frequencies of IL-17A (rs3819025) were significantly different between GDM and controls (p = 0.01). Using additive models, IL-17A (rs3819025) and. TNF-α (rs1800629) were found to be independently associated with increased risk of GDM (odds ratio [OR]: 2.867; 95 % confidence interval [CI]: 1.171-7.017; p = 0.021; and OR: 12.163; 95 %CI: 1.368-108.153; p = 0.025, respectively). In GDM with IL-17A (rs3819025), there was a significant negative correlation with lipocalin-2 and PAI-1 levels (p = 0.038 and p = 0.004, respectively).

CONCLUSION

The results of this study highlight the need for genetic testing to predict/prevent GDM, and the importance of evaluating adipokine/adipocytokine levels in Thai GDM women.

Effect of Carbohydrate-Restricted Dietary Pattern on Insulin Treatment Rate, Lipid Metabolism and Nutritional Status in Pregnant Women with Gestational Diabetes in Beijing, China

Carbohydrates play an important role in blood glucose control in pregnant women with GDM. Carbohydrate-restricted dietary (CRD) pattern for gestational diabetes mellitus (GDM) has been widely used in clinics, but the change in insulin utilization rate beyond CRD intervention in GDM remains unclear. The aim of the present study was to explore the application of insulin in pregnancy with GDM, as well as the influence of CRD pattern on lipid metabolism and nutritional state. A retrospective study of 265 women with GDM who delivered in Peking University People’s Hospital from July 2018 to January 2020 was conducted using a questionnaire survey. Women were divided into a CRD group or a control group according to whether they had received CRD intervention during pregnancy. There was no statistically significant difference in the rate of insulin therapy between the two groups (p > 0.05), the initial gestational week of the CRD group combined with insulin treatment was significantly higher than that of the control group (p < 0.05), and the risk of insulin therapy was positively correlated with fasting plasma glucose (FPG) in early pregnancy (p < 0.05). The incidence of abnormal low-density lipoprotein cholesterol levels in the CRD group was significantly lower than that in the control group (p < 0.05). There were no significant differences in nutritional indexes between the two groups. The results indicate that CRD intervention may be effective in delaying the use of insulin and improving the blood lipids metabolism during GDM pregnancy, while nutritional status may not be significantly affected under CRD intervention, and a high FPG in early pregnancy with GDM may be a risk factor for combined insulin therapy with CRD intervention.

Formyl peptide receptor-2 is upregulated in the blood and placenta of patients with gestational diabetes mellitus

Aim

To investigate the expression of formyl peptide receptor 2 (FPR2) in maternal blood, umbilical blood, and placenta of patients with gestational diabetes mellitus (GDM), and to analyze the changes of other pro‐inflammatory cytokines in blood, including interleukin 33 (IL‐33), IL‐1β, tumor necrosis factor alpha (TNF‐α), and C‐reactive protein (CRP), so as to reveal the pathogenesis of GDM.

Methods

FPR2, IL‐33, IL‐1β, T TNF‐α, and CRP in maternal blood and umbilical cord blood of 50 pregnant women with GDM and 30 normal pregnant women were analyzed by ELISA method to explore the correlation between inflammatory factors and blood glucose. The expression of FPR2 in placental tissues was analyzed by PCR and immunohistochemistry.

Results

The expression of FPR2 in maternal blood of gestational diabetes patients was significantly higher than that of normal pregnant women, and other inflammatory factors IL‐33 and IL‐1β in maternal blood were also significantly increased. The expression of FPR2 in umbilical cord blood of gestational diabetes was higher than that of normal pregnant women, but the difference was not significant. Other inflammatory factors IL‐33, IL‐1β, and CRP in umbilical cord blood were also significantly increased. The expression of FPR2mRNA and protein in placental tissues of gestational diabetes was significantly higher than that of normal pregnant women.

Conclusions

The level of FPR2, IL‐33, and IL‐1β in maternal blood was related to the pathogenesis of GDM and these inflammatory factors could be used as special candidate direction of marks for the prevention, clinical treatment and drug design of GDM, laying a new theoretical foundation for the treatment of GDM.

The cardio-ankle vascular index as a predictor of adverse pregnancy outcomes

OBJECTIVE

To assess the association between maternal hemodynamic parameters; cardio-ankle vascular index (CAVI), representing arterial stiffness; mean arterial pressure (MAP), uterine artery pulsatility index (Ut-PI), and adverse pregnancy outcomes including preeclampsia (PE), fetal growth restriction (FGR), and gestational diabetes mellitus (GDM).

METHODS

A prospective cohort study was conducted on low-risk pregnancies. All were serially measured for the mean CAVI, MAP, and Ut-PI for four times at gestational age (GA) 11-14, 18-22, 28-32, and after 36 weeks. Also, the women were followed up for pregnancy outcomes, focusing on PE, FGR, and GDM.

RESULTS

Of 335 recruited cases meeting the inclusion criteria, 16 cases developed PE, 24 cases had FGR, and 83 cases had GDM. Compared to the non-PE group, women developing PE had a significant increase in CAVI at 18-22, 28-32, and after 36 weeks (P-value = 0.021, 0.003, and <0.001, respectively), a significant increase in MAP at all of the four periods (P-value < 0.001, for all periods), and a significant increase in Ut-PI during GA 18-22 weeks (P-value = 0.021). In pregnancies with FGR, there was a significant increase of CAVI at GA 18-22, 28-32 and after 36 weeks (P-value = 0.012, 0.015, and 0.004, respectively), an increase in Ut-PI in all gestational periods (P-value < 0.05) but no changes of MAP throughout pregnancy. In GDM, the three parameters were not significantly different from those in the non-GDM group in all of the four periods. CAVI could predict PE and FGR with AUC of 0.655-0.835 and 0.673-0.760, respectively. CAVI added predictive values when combined with MAP or Ut-PI.

CONCLUSION

Increased CAVI, like MAP and Ut-PI, can be used as a predictor of PE and FGR but not GDM. Also, it has an added predictive value when combined with MAP or Ut-PI.

Research Progress on Gestational Diabetes Mellitus and Endothelial Dysfunction Markers

Gestational diabetes mellitus (GDM) is the onset or first recognition of diabetes during pregnancy in women with normal glucose metabolism or potentially impaired glucose tolerance before pregnancy. Studies have shown that vascular endothelial cells (VECs) are an important target organ of insulin, which is injured by multiple factors in the case of GDM, thereby leading to worsened insulin resistance (IR) and the further development of GDM. When VECs are abnormal, there will be changes in the content of a variety of cell markers, which may be helpful for the clinical prediction and diagnosis of GDM. This study attempted to investigate the mechanism and markers of VECs injury in GDM patients.

Predictive and diagnostic biomarkers for gestational diabetes and its associated metabolic and cardiovascular diseases

Gestational diabetes mellitus (GDM) is defined as the presence of high blood glucose levels with the onset, or detected for the first time during pregnancy, as a result of increased insulin resistance. GDM may be induced by dysregulation of pancreatic β-cell function and/or by alteration of secreted gestational hormones and peptides related with glucose homeostasis. It may affect one out of five pregnancies, leading to perinatal morbidity and adverse neonatal outcomes, and high risk of chronic metabolic and cardiovascular injuries in both mother and offspring. Currently, GDM diagnosis is based on evaluation of glucose homeostasis at late stages of pregnancy, but increased age and body-weight, and familiar or previous occurrence of GDM, may conditionate this criteria. In addition, an earlier and more specific detection of GDM with associated metabolic and cardiovascular risk could improve GDM development and outcomes. In this sense, 1st-2nd trimester-released biomarkers found in maternal plasma including adipose tissue-derived factors such as adiponectin, visfatin, omentin-1, fatty acid-binding protein-4 and retinol binding-protein-4 have shown correlations with GDM development. Moreover, placenta-related factors such as sex hormone-binding globulin, afamin, fetuin-A, fibroblast growth factors-21/23, ficolin-3 and follistatin, or specific micro-RNAs may participate in GDM progression and be useful for its recognition. Finally, urine-excreted metabolites such as those related with serotonin system, non-polar amino-acids and ketone bodies, may complete a predictive or early-diagnostic panel of biomarkers for GDM.

Role of immunological markers in gestational diabetes mellitus-a brief review

Gestational Diabetes Mellitus (GDM) is a condition which develops due to insulin resistance. There are a number of immunological markers (IL-6, TNF-α, IL-10, etc), which play significant role during normal pregnancy and their irregular levels could likely cause some level of insulin resistance. There are studies which have compared the levels of different immunological mediators in GDM affected females and their healthy controls, but their findings are little controversial. Some of the studies have reported increased levels of IL-6, TNF-α, adiponectin, leptin, in females affected with GDM, while others do not confirm this. We have tried to summarize, in this short review, the findings of research studies being conducted globally, which have reported the association of insulin resistance, GDM and immunological markers. Our review suggests that there is a need for high quality data on the immunological parameters associated with GDM, especially from India.

The two-stage placental model of preeclampsia: An update

Early-onset preeclampsia has been linked to poor placentation and fetal growth restriction, whereas late-onset preeclampsia was suggested to result from maternal factors. We have proposed an alternative model, suggesting that both early- and late-onset preeclampsia result from placental syncytiotrophoblast stress. This stress represents a common endpoint of several Stage 1 processes, promoting the clinical stage 2 of preeclampsia (new-onset hypertension and proteinuria or other signs of end-organ dysfunction), but the causes and timing of placental malperfusion differ. We have suggested that late-onset preeclampsia, without evidence of poor spiral artery remodelling, may be secondary to intraplacental (intervillous) malperfusion due to mechanical restrictions. As the growing placenta reaches its size limit, malperfusion and hypoxia occurs. This latter pathway reflects what is observed in postmature or multiple pregnancies. Our revised two-stage model accommodates most risk factors for preeclampsia including primiparity, chronic pre-pregnancy disease (e.g. obesity, diabetic-, chronic hypertensive-, and some autoimmune diseases), and pregnancy risk factors (e.g. multiple or molar pregnancies, gestational diabetes or hypertension, and low circulating Placental Growth Factor). These factors may increase the risk of progressing to the second stage of preeclampsia (both early- and late-onset) by affecting one of or both pathways leading to Stage 1, as well as potentially accelerating the steps towards Stage 2, including priming the maternal cardiovascular susceptibility to inflammatory factors shed by the placenta. This paper reviews previous preeclampsia findings and concepts, which fit with the revised two-stage model, and argues that "maternal" preeclampsia does not exist, as all preeclampsia requires a placenta.

The Role of Inflammation in the Development of GDM and the Use of Markers of Inflammation in GDM Screening

Gestational diabetes mellitus is a hyperglycaemic state first recognised in pregnancy. GDM affects both mother and child. Women with GDM and their new-borns are at risk of developing type 2 diabetes in the future. The screening and diagnostic criteria for GDM are inconsistent and thus novel biomarkers of GDM are required to strengthen the screening and diagnostic processes in GDM. Chronic low-grade inflammation is linked to the majority of the well-established risk factors of GDM such as old age, obesity and PCOS. This review provides an overview of the present knowledge on the pathology of GDM, the screening criteria applied, the role of inflammation in the development of GDM and the use of markers of inflammation namely cytokines, oxidative stress markers, lipids, amino acids and iron markers in screening and diagnosis of GDM.

Impaired microvascular reactivity in gestational diabetes is associated with altered glycemic parameters

OBJECTIVES

To assess microvascular reactivity and glycemic parameters in GDM compared to age and GA matched controls.

METHODS

This study involved 21 GDM patients and 31 controls. Microvascular reactivity was assessed using LDF and PORH. Microvascular parameters; PORH_max , PORH_peak , and time to peak perfusion (Tp) were recorded after the release of 3 minutes' upper arm occlusion. HOMA-IR was performed to evaluate insulin resistance.

RESULTS

Average age and GA for subjects were 32.9 years and 29.2 weeks. Mean FBG and a 2-hour postprandial for GDM and controls were 4.87 ± 0.71 vs 3.99 ± 0.59 mmol/L; P < 0.001 and 9.50 ± 1.8 vs 5.67 ± 1.0 mmol/L; P < 0.001. Fasting insulin (13.88 ± 18.9 vs 8.37 ± 11.0 μLU/mL; P = 0.031) and HOMA-IR (3.14 ± 4.6 vs 1.52 ± 2.2; P = 0.004) were higher in GDM. Tp was prolonged in GDM (16.27 ± 4.3 vs 13.86 ± 2.1 seconds; P = 0.011). Positive correlations were seen between Tp and FBG and 2-hour postprandial levels.

CONCLUSION

Tp was prolonged in GDM compared to age-matched controls, indicating impaired microvascular reactivity.

The impact of omega-3 fatty acid supplementation on glycemic control in patients with gestational diabetes: a systematic review and meta-analysis of randomized controlled studies

Background: Omega-3 fatty acid supplementation shows some treatment efficacy for gestational diabetes. This systematic review and meta-analysis is conducted to investigate the efficacy of omega-3 fatty acid supplementation for glycemic control in patients with gestational diabetes.Methods: The databases including PubMed, Embase, Web of science, EBSCO, and Cochrane Library databases are systematically searched for collecting the randomized controlled trials (RCTs) regarding the efficacy of omega-3 fatty acid versus placebo for gestational diabetes.Results: This meta-analysis has included seven RCTs. Compared with placebo group in patients with gestational diabetes, omega-3 fatty acids supplementation results in remarkably reduced fasting plasma glucose (FPG) (standard mean difference (std. MD) = -0.56; 95% confidence interval (CI) = -0.87 to -0.24; p = .0005), homeostatic model of assessment for insulin resistance (HOMA-IR) (std. MD = -0.52; 95% CI = -0.83 to -0.21; p = .001), but has no statistical impact on macrosomia (risk ratio (RR) = 0.48; 95% CI = 0.22-1.02; p = .06), newborns' hyperbilirubinemia (RR = 0.46; 95% CI = 0.19-1.10; p = .08), nitric oxide (NO) (std. MD = 0.17; 95% CI = -0.64-0.98; p = .68), preterm delivery (RR = 1.75; 95% CI = 0.08-3.80; p=.16) and preeclampsia (RR =0.74; 95% CI = 0.26-2.16; p = .59). However, notably decreased high sensitivity C-reactive protein (hs-CRP) is revealed after omega-3 fatty acids supplementation (std. MD = -1.14; 95% CI = -2.0 to -0.29; p = .009).Conclusions: Omega-3 fatty acids supplementation can provide substantially beneficial effects on glycemic control and inflammatory response for gestational diabetes.

Haemodynamic differences amongst women who were screened for gestational diabetes in comparison to healthy controls

AIM

To assess the changes in haemodynamics amongst pregnant women who were screened for gestational diabetes mellitus (GDM) in comparison to low-risk healthy pregnant controls.

METHODOLOGY

A total of 120 pregnant women of mean (standard deviation) age 31.03 (5.41) years who attended their oral glucose tolerance test as part of the national screening for GDM (study), and 60 low-risk healthy pregnant women (control) of mean age 29.71 (5.33) years, were invited to participate in this study. All women included in the study booked at the University Hospitals of Leicester NHS Trust and fulfilled the relevant inclusion criteria. Non-invasive assessment of arterial stiffness and cardiac output were undertaken on participants between 26 and 28 weeks of pregnancy. The mean difference between GDM and low-risk group for each of the arterial stiffness and cardiac output measurements was assessed by a two-sample unpaired t-test.

RESULTS

Significant differences were found between the study and control groups for brachial (-64.5 vs. -69.5, p < 0.04) and aortic augmentation indices (5.2 vs. 2.7, p = 0.04), though there was no significant difference for PWV (8.3 vs. 8.1, p = 0.49). Cardiac output (7.6 vs. 7.0, p = 0.011), stroke volume (84.4 vs. 76.9, p = 0.013) and central mean arterial pressure (71 vs. 58, <0.001) were also significantly different between groups. However, no significant differences were reported for heart rate, systolic and diastolic blood pressure, or total peripheral resistance.

CONCLUSION

Pregnant women at risk of GDM between gestational weeks 26 and 28 had significantly increased measures of arterial stiffness, as assessed by brachial and aortic augmentation indices, compared with low-risk healthy controls. Whether these women are at greater long-term cardiovascular disease risk warrants further investigation.

Blunted cerebral oxygenation during exercise in women with gestational diabetes mellitus: associations with macrovascular function and cardiovascular risk factors

AIM/HYPOTHESIS

This cross-sectional, observational, controlled study examined cerebral oxygenation during exercise, an index of cerebrovascular function and cortical activation, in pregnancies complicated by gestational diabetes mellitus (GDM) and unaffected pregnancies. The association of cerebral oxygenation with macrovascular and cardiovascular function indices was also evaluated.

MATERIAL AND METHODS

Vascular function and structure [aortic pulse-wave-velocity (PWV), augmentation index (AI), carotid intima-media thickness], as well as 24-hour ambulatory blood pressure (BP) were assessed in women with GDM (n = 21) and uncomplicated pregnancies (n = 16), at 26-32 gestational weeks. Changes in cerebral oxygenation [oxy- (O₂Hb), deoxy- (HHb) and total- (tHb) hemoglobin] were continuously recorded by near-infrared spectroscopy (NIRS) during intermittent handgrip exercise. Beat-by-beat BP and systemic vascular resistance (SVR) were assessed (Finapres).

RESULTS

Women with GDM had higher AI than controls. During exercise, women with GDM maintained a smaller force (p < 0.05), despite similar ratings of perceived exertion. Despite similar increases in BP during exercise, the GDM group exhibited a lower average and total (AUC) increase in cerebral-O₂Hb than controls (p < 0.05). In addition, GDM exhibited a slower rate of cerebral-O₂Hb decay during recovery (p < 0.05). SVR was lower in GDM compared to controls throughout the protocol (p < 0.01). Cerebral oxygenation indices were correlated with PWV and AI (p < 0.05).

CONCLUSIONS

This study provided novel evidence for blunted cerebral oxygenation during exercise in women with GDM compared to uncomplicated pregnancies, suggesting a link between reduced cerebrovascular function with exercise intolerance in GDM. Cerebral oxygenation during physical stress was correlated with macrovascular function and cardiovascular risk factors. More studies are needed to examine whether this impaired cerebral oxygenation reflects early cerebrovascular disease.

The effects of metformin on maternal haemodynamics in gestational diabetes mellitus: A pilot study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major clinical challenge and is likely to remain so as the incidence of GDM continues to increase.

AIM

To assess longitudinal changes in maternal haemodynamics amongst women diagnosed with GDM requiring either metformin or dietary intervention in comparison to low-risk healthy controls.

METHODOLOGY

Fifty-six pregnant women attending their first appointment at the GDM clinic and 60 low-risk healthy pregnant controls attending their routine antenatal clinics were recruited and assigned to three groups: GDM Metformin (GDM-M), GDM Diet (GDM-D) and Control. Non-invasive assessment of maternal haemodynamics, using recognised measures of arterial stiffness and central blood pressure (Arteriograph®), were undertaken under controlled conditions within four gestational windows: antenatal; AN1 (26-28 weeks), AN2 (32-34 weeks) and AN3 (37-40 weeks), and postnatal (PN) (6-8 weeks after delivery). Data were analysed using a linear mixed model incorporating gestational age and other relevant predictors, including age, blood pressure (BP), baseline bodyweight and pulse as fixed effects, and patient as a random effect.

RESULTS

Fitted linear mixed models showed evidence of a two-way interaction effect between groups (GDM-D, GDM-M and Control) and stages of gestation (AN1, AN2, AN3 and PN) for maternal haemodynamic parameters: brachial artery augmentation index (AIx) (p = 0.004), aortic AIx (p = 0.008), and central systolic BP (p = 0.001). However, differences in respect of aortic pulse wave velocity (p = 0.001) and heart rate (p < 0.001) were only significant for gestational stage. At AN2, we did not observe any evidence that the mean brachial Aix in the GDM-M was different from the control group (p = 0.158).

CONCLUSION

AIx and central systolic BP measures of arterial stiffness are adversely affected by GDM in comparison to controls during pregnancy. The possible beneficial effects of metformin therapy seen at 32 to 34 weeks of gestation require further exploration.

Expression of intercellular adhesion molecule-1 in umbilical vascular of pregnant women with gestational diabetes mellitus and the clinical significance

The purpose of this study was to investigate the expression of intercellular adhesion molecule-1 (ICAM-1) in umbilical vascular of pregnant women with gestational diabetes mellitus (GDM) and the clinical significance. A total of 103 pregnant women with GDM were selected in the First Hospital of Lanzhou University and the Second Affiliated Hospital of Xi'an Jiaotong University from January 2016 to December 2016 as GDM group. At the same time, 106 normal pregnant women were selected as control group. i) General information of the two groups of pregnant women including age, gestational age, gravida, parity, BMI, systolic blood pressure and diastolic blood pressure were compared; ii) the laboratory indicators of the two groups of pregnant women including fasting blood glucose, glycosylated hemoglobin (HbA1c), umbilical cord arterial pH, partial pressure of oxygen (pO₂) and carbon dioxide (pCO₂) in umbilical artery were compared; iii) expression of ICAM-1 in umbilical vascular was detected by immunohistochemistry; iv) expression levels of ICAM-1 in umbilical vascular of the two groups of patients were compared. i) There was no significant difference in the age, smoking, gestational age, gravida, parity, BMI, systolic blood pressure and diastolic blood pressure between the two groups (p>0.05); ii) no significant differences in HbA1c, umbilical cord arterial pH, pO₂ and pCO₂ were found between the groups (p>0.05); iii) ICAM-1 was expressed in umbilical vessels of both groups of pregant women; iv) no significant differences in expression levels of ICAM-1 in umbilical artery and umbilical vein endothelial cells were found between the groups (p>0.05). Therefore, GDM patients with good blood glucose control have no umbilical cord endothelial cell damage.

A Randomized Double-Blinded, Placebo-Controlled Trial Investigating the Effect of Fish Oil Supplementation on Gene Expression Related to Insulin Action, Blood Lipids, and Inflammation in Gestational Diabetes Mellitus-Fish Oil Supplementation and Gestational Diabetes

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, and it is mostly associated with postpartum diabetes, insulin resistance, and dyslipidemia. Fish oil (omega-3) supplementation has been shown to reduce the risk of different chronic diseases such as cardiovascular disease, type 2 diabetes, and cancers, though the evidence of its impact on gestational diabetes is scarce. Our goal in this study was to determine the effect of fish oil administration on gene expression related to insulin action, blood lipids, and inflammation in women with GDM. Participants with GDM (n = 40), aged 18–40 years, were randomized to take either 1000 mg fish oil capsules, containing 180 mg eicosapentaenoic acid and 120 mg docosahexaenoic acid (n = 20), or placebo (n = 20) twice a day for 6 weeks. Gene expression related to insulin, lipids, and inflammation was quantified in peripheral blood mononuclear cells (PBMCs) of GDM women using Reverse Transcription Polymerase Chain Reaction (RT-PCR) method. Results of RT-PCR indicated that omega-3 supplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.04) in PBMCs of patients with GDM, compared with the placebo. In addition, gene expression of the low-density lipoprotein receptor (LDLR) (P < 0.001), interleukin-1 (IL-1) (P = 0.007), and tumor necrosis factor alpha (TNF-α) (P = 0.01) was downregulated in PBMCs of women with GDM, following omega-3 supplementation. No significant effect of omega-3 supplementation was indicated on gene expression of IL-8 in PBMCs of patients with GDM. Overall, fish oil supplementation for 6 weeks in women with GDM significantly improved gene expression of PPAR-γ, IL-1, and TNF-α, but not gene expression of IL-8.

The modulatory role of cytokines IL-4 and IL-17 in the functional activity of phagocytes in diabetic pregnant women

The study investigated the role of cytokines IL-4 and IL-17 in the modulation of the functional activity of mononuclear phagocytes in diabetic pregnant women with hyperglycemia. Sixty pregnant women were assigned to the following groups: nondiabetic (ND), mild gestational hyperglycemia (MGH), gestational diabetes mellitus (GDM), or type 2 diabetes mellitus (DM2). The functional activity of phagocytes from maternal blood, cord blood, and colostrum was assessed by determining their superoxide release, phagocytosis, microbicidal activity, and intracellular Ca²⁺ release. Irrespective of glycemic status, colostrum and blood cells treated with IL-4 and IL-17 increased superoxide release in the presence of enteropathogenic Escherichia coli (EPEC). The highest phagocytosis rate was observed in cells from the DM2 group treated with IL-4. In all the groups, phagocytes from colostrum, maternal blood, and cord blood exhibited higher microbicidal activity against EPEC when treated with cytokines. IL-17 increased intracellular Ca²⁺ release by colostrum phagocytes in diabetic groups. The results indicate that the IL-4 and IL-17 modulate the functional activity of phagocytes in the maternal blood, cord blood, and colostrum of diabetic mother. The natural immunity resulting from the interaction between the cells and cytokines tested may be an alternative procedure to improve the prognosis of maternal and newborn infections.

Roles of Inflammation and Depression in the Development of Gestational Diabetes

Inflammation, the body's response to harmful external agents, has long been found to be associated with depressive symptoms. The relationship between inflammation and depression is well established in the general population of people with depression, but is less so among perinatal women. Depression in the perinatal period is a common disorder, however available data do not indicate that there is a specific inflammatory picture associated with perinatal depression. We suggest that perinatal depression may be a heterogeneous construct, and that inflammation may be relevant to it in the context of other inflammatory morbidities of pregnancy. In this review we explore the available support for the hypothesis that inflammation associated with depression can represent a precipitating insult for the development of gestational diabetes, a known inflammatory morbidity of pregnancy.

Role of Plasminogen Activator Inhibitor Type 1 in Pathologies of Female Reproductive Diseases

Normal pregnancy is a state of hypercoagulability with diminishing fibrinolytic activity, which is mainly caused by an increase of plasminogen activator inhibitor type 1 (PAI-1). PAI-1 is the main inhibitor of plasminogen activators, including tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). In human placentas, PAI-1 is expressed in extravillous interstitial trophoblasts and vascular trophoblasts. During implantation and placentation, PAI-1 is responsible for inhibiting extra cellular matrix (ECM) degradation, thereby causing an inhibition of trophoblasts invasion. In the present study, we have reviewed the literature of various reproductive diseases where PAI-1 plays a role. PAI-1 levels are increased in patients with recurrent pregnancy losses (RPL), preeclampsia, intrauterine growth restriction (IUGR), gestational diabetes mellitus (GDM) in the previous pregnancy, endometriosis and polycystic ovary syndrome (PCOS). In general, an increased expression of PAI-1 in the blood is associated with an increased risk for infertility and a worse pregnancy outcome. GDM and PCOS are related to the genetic role of the 4G/5G polymorphism of PAI-1. This review provides an overview of the current knowledge of the role of PAI-1 in reproductive diseases. PAI-1 represents a promising monitoring biomarker for reproductive diseases and may be a treatment target in the near future.

Increased intestinal permeability, measured by serum zonulin, is associated with metabolic risk markers in overweight pregnant women

BACKGROUND

Increased intestinal permeability with subsequent metabolic endotoxemia, i.e., elevated circulating levels of bacterial lipopolysaccharide, LPS, has been introduced as a novel initiator of obesity related metabolic disturbances in non-pregnant individuals. The objective was to investigate the extent to which intestinal permeability, measured by serum zonulin concentration, is related to metabolic endotoxemia and metabolic risk markers in overweight pregnant women.

METHODS

This was a cross-sectional study including 100 pregnant overweight women in early pregnancy. Serum zonulin was analyzed using ELISA, and markers for metabolic endotoxemia (LPS), inflammation (high-sensitive C-reactive protein and glycoprotein acetylation GlyA), glucose metabolism (fasting glucose and insulin), and lipid metabolism were measured.

RESULTS

Higher serum zonulin concentration associated positively with LPS (P=0.02), inflammatory markers (P<0.001), insulin (P<0.001), insulin resistance (P<0.001), and triglycerides (P=0.001), and negatively with insulin sensitivity (P=0.001) (ANOVA with Tukey's corrections or Kruskal-Wallis nonparametric test with Bonferroni correction for zonulin quartiles). All the observed associations were confirmed (P<0.015) in a linear regression model adjusted with potential confounding factors. Both LPS and GlycA showed positive relationship with insulin resistance, serum insulin, triglycerides, total and LDL-cholesterol and negative relationship with insulin sensitivity (P≤0.03) in the univariate linear regression. Positive relationship was also found between LPS and HDL-cholesterol (P=0.03).

CONCLUSIONS

Our findings suggest that increased serum zonulin concentration, i.e., increased intestinal permeability, contributes to metabolic endotoxemia, systemic inflammation, and insulin resistance in overweight pregnant women. By reinforcing intestinal barrier, it may be possible to manipulate maternal metabolism during pregnancy with subsequent health benefits.

Altered cytokine network in gestational diabetes mellitus affects maternal insulin and placental-fetal development

Pregnancy is characterized by an altered inflammatory profile, compared to the non-pregnant state with an adequate balance between pro-and anti-inflammatory cytokines needed for normal development. Cytokines are small secreted proteins expressed mainly in immunocompetent cells in the reproductive system. From early developmental stages onward, the secretory activity of placenta cells clearly contributes to increase local as well as systemic levels of cytokines. The placental production of cytokines may affect mother and fetus independently. In turn because of this unique position at the maternal fetal interface, the placenta is also exposed to the regulatory influence of cytokines from maternal and fetal circulations, and hence, may be affected by changes in any of these. Gestational diabetes mellitus (GDM) is associated with an overall alteration of the cytokine network. This review discusses the changes that occur in cytokines post GDM and their negative effects on maternal insulin and placental-fetal development.

Impact of Systemic Inflammation on the Progression of Gestational Diabetes Mellitus

With increasing rates of obesity and new diagnostic criteria for gestational diabetes mellitus (GDM), the overall prevalence of GDM is increasing worldwide. Women with GDM have an increased risk of maternal and fetal complications during pregnancy as well as long-term risks including higher prevalence of type 2 diabetes mellitus and cardiovascular disease. In recent years, the role of immune activation and inflammation in the pathogenesis of GDM has gained increasing attention. This monograph explores the current state of the literature as regards the expression of markers of inflammation in the maternal circulation, placenta, and adipose tissue of women with GDM.

First trimester screening for gestational diabetes mellitus by maternal factors and markers of inflammation

OBJECTIVE

To examine the potential role of maternal serum levels of tumor necrosis factor-α (TNF-α) and high sensitivity C-reactive protein (Hs-CRP) in the first trimester of pregnancy in the prediction of gestational diabetes mellitus (GDM).

METHODS

Maternal serum TNF-α and Hs-CRP concentrations were measured in a case-control study of singleton pregnancies at 11-13 weeks' gestation, which included 200 cases that subsequently developed GDM and 800 unaffected controls. Measured levels of TNF-α and Hs-CRP were expressed as multiples of the median (MoM) after adjustment for maternal characteristics and history. The performance of screening for GDM by maternal factors and MoM values of TNF-α and Hs-CRP was evaluated by the area under the receiver operating characteristic curves (AUROC).

RESULTS

In the GDM group, compared to the normal group, the median TNF-α was significantly increased (1.303 MoM, interquartile range [IQR] 1.151-1.475 vs. 1.0 MoM, IQR 0.940-1.064; p=0.031) and the median Hs-CRP was not significantly different (1.113 MoM, IQR 0.990-1.250 vs. 1.0 MoM, IQR 0.943-1.060; p=0.084). In the prediction of GDM, the AUROC for maternal characteristics with TNF-α or Hs-CRP was not significantly different than the AUROC for maternal characteristics alone (p=0.5055 and p=0.2197, respectively).

CONCLUSIONS

In pregnancies that develop GDM there is no evidence of an inflammatory response at 11-13 weeks' gestation and the levels of serum TNF-α and Hs-CRP are not useful in first-trimester screening for GDM.

Aortic Stiffness and Cardiovascular Risk in Women with Previous Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a significant risk factor for cardiovascular disease (CVD) in later life, but the mechanism remains unclear. The aim of the study was to investigate indices of glucose metabolism, dyslipidemia, and arterial stiffness (as measured by pulse wave velocity (PWV)), in women with and without a history of GDM, using both the old WHO and new IADPSG diagnostic criteria, at 5 years after the index pregnancy. Dyslipidemia and PWV were used as surrogate markers for CVD risk. The population-based prospective cohort included 300 women from the original STORK study. All participants had an oral glucose tolerance test (OGTT) during pregnancy. Five years later, the OGTT was repeated along with dual-energy x-ray absorptiometry, lipid analysis, and PWV analysis. Measurements were compared between those women who did and did not have GDM based on both the WHO and IADPSG criteria. We found that women with GDM based on the old WHO criteria had higher CVD risk at 5 years than those without GDM, with markedly elevated PWV and more severe dyslipidemia (higher triglycerides (TG)/HDL cholesterol ratio). After adjusting for known risk factors, the most important predictors for elevated PWV and TG/HDL-C ratio at 5-year follow-up were maternal age, BMI, GDM, systolic blood pressure, and indices of glucose metabolism in the index pregnancy. In conclusion, we found a higher risk for CVD, based on the surrogate markers PWV and TG/HDL-C ratio, at 5-year follow-up in women diagnosed with GDM in the index pregnancy when using the old WHO diagnostic criteria.

Adipokines in gestational diabetes

Gestational diabetes is characterised by glucose intolerance with onset or first recognition during pregnancy. The disease shows facets of the metabolic syndrome including obesity, insulin resistance, and dyslipidaemia. Adipokines are a group of proteins secreted from adipocytes, which are dysregulated in obesity and contribute to metabolic and vascular complications. Recent studies have assessed the role of various adipokines including leptin, adiponectin, tumour necrosis factor α (TNFα), adipocyte fatty acid-binding protein (AFABP), retinol-binding protein 4 (RBP4), resistin, NAMPT, SERPINA12, chemerin, progranulin, FGF-21, TIMP1, LCN2, AZGP1, apelin (APLN), and omentin in gestational diabetes. This Review provides an overview of these key adipokines, their regulation in, and potential contribution to gestational diabetes. Based on the evidence so far, the adipokines adiponectin, leptin, TNFα, and AFABP seem to be the most probable candidates involved in the pathophysiology of gestational diabetes.

The changes of neutrophil gelatinase-associated lipocalin in plasma and its expression in adipose tissue in pregnant women with gestational diabetes

AIMS

To investigate plasma levels and the expression of neutrophil gelatinase-associated lipocalin (NGAL) in subcutaneous adipose tissue (SAT) in patients with gestational diabetes mellitus (GDM).

METHODS

The study recruited 260 Chinese women divided into three groups: 96 were healthy pregnant women with pre-pregnancy body mass index (pre-pregnancy BMI) below 25kg/m(2) (GROUP 1), 84 were women with GDM with pre-pregnancy BMI below 25kg/m(2) (GROUP 2) and 80 were women with GDM with pre-pregnancy BMI over 25kg/m(2) (GROUP 3). Laboratory and anthropometric measurements were recorded and NGAL plasma levels were determined by ELISA for subjects in all groups. Real-time RT-PCR and Western blotting were used to assess the relative mRNA and protein expression of NGAL and tumor necrosis factor-α (TNF-α) in SAT (30 cases in each group).

RESULTS

Our results demonstrated statistically significant elevation in plasma NGAL concentrations in GROUP 2 and GROUP 3 compared with GROUP 1 (p<0.001 for both group comparisons). Moreover, SAT NGAL mRNA (p<0.001 and p<0.001, respectively) and protein (p<0.001 and p<0.001, respectively) expression levels were higher in GROUP 3 than in both GROUP 1 and GROUP 2. Correlations were noted between the plasma NGAL concentration and various parameters of insulin resistance.

CONCLUSIONS

Plasma NGAL may play a role in the development of insulin resistance in GDM, and the high levels of NGAL expression in SAT in overweight women with GDM suggests that NGAL in SAT is associated with obesity in women with GDM.

Increased endothelial inflammation, sTie-2 and arginase activity in umbilical cords obtained from gestational diabetic mothers

Objective

The aim of this study was to determine subclinical inflammation in umbilical vein derived endothelial cells (HUVECs) obtained from Asian Indian subjects with gestational diabetes (GDM) and to determine levels of angiogenic factors and arginase activity in their cord blood.

Methods

This case-control study included 38 control and 30 GDM subjects. Subjects were confirmed as GDM based on 75g oral glucose tolerance test (OGTT) conducted in the second trimester of pregnancy. Angiogenic markers and arginase activity were measured in cord blood by ELISA and colorimetric methods respectively. Endothelial inflammation was assessed through adhesion of PKH26-labelled leukocytes onto HUVEC monolayer obtained from the study groups. Gene and surface expression of adhesion molecules were confirmed via reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry respectively.

Results

The study revealed increased adhesion of leukocytes to HUVECs isolated from GDM subjects compared to controls. HUVECs of babies born to GDM mothers had increased surface and mRNA expression of E-selectin. sTie2 levels were significantly higher in the cord blood for GDM subjects (3869 ± 370 ng/L) compared to controls (3045 ± 296 ng/L). Furthermore, arginase activity was higher in cord blood of GDM mothers as opposed to the control group (7.75 ± 2.4 µmoles of urea/ml/hour vs 2.88 ±0.49 µmoles of urea/ml/hour; p-value= 0.019). Spearman’s correlation analysis revealed positive correlation of cord blood arginase activity with glucose intolerance (ρ=0.596, p=0.004) and post load glucose values (ρ=0.472, p=0.031) of mothers observed during the second trimester of pregnancy.

Conclusions

HUVECs derived from Asian Indian GDM mothers, exhibit signs of sub-clinical endothelial inflammation along with increased levels of sTie2 and arginase activity in their cord blood serum.

Hemodynamic and hormonal patterns of untreated essential hypertension in men and women

BACKGROUND

Knowledge of hemodynamic factors accounting for the development of hypertension should help to tailor therapeutic approaches and improve blood pressure control. Few data exist regarding sex differences of hemodynamic factors contributing to hypertension progression among patients with untreated nondiabetic stage I and II prehypertension (PreHyp) as defined by the Joint National Committee-7 guidelines (JNC-7).

METHODS

We utilized noninvasive impedance cardiography, applanation tonometry and plasma measures of angiotensin II, angiotensin (1-7), serum aldosterone, high-sensitivity C-reactive protein (hs-CRP) and cytokine biomarkers of inflammation to characterize the hemodynamic and hormonal profile of 100 patients with untreated hypertension (39 women).

RESULTS

Despite there being no differences between women and men in terms of office blood pressure, heart rate and body mass index, men demonstrated lower values of pulse pressure, systemic vascular resistance, brachial artery pulse wave velocity and augmentation index. In each of the three hypertension categories, the increased blood pressure in men was associated with significant augmentations in stroke volume and cardiac output compared with women. Sex-related hemodynamic differences were associated in women with higher plasma levels of leptin, hs-CRP, plasma angiotensin II and serum aldosterone, and no differences in the serum concentrations of cytokinins. In women but not men, hs-CRP correlated with plasma concentrations of transforming growth factor β1 (TGFβ1) and body weight; in addition, plasma TGFβ1 correlated with levels of serum vascular cell adhesion molecule 1.

CONCLUSION

The impact of sex differences in the hemodynamic factors accounting for the elevation in arterial pressure in subjects with essential hypertension has been poorly characterized or this information is not available. We suggest that this gap in knowledge may adversely influence choices of drug treatment since our study shows for the first time significant differences in the hemodynamic and hormonal mechanisms accounting for the increased blood pressure in women compared to men.

Pregnancy Complications and Later Development of Hypertension

Pregnancy complications such as preeclampsia and diabetes affect approximately 5 to 10 % of all pregnancies and compromise maternal and fetal health during gestation. Complications during pregnancy may also contribute to the development of hypertension and future cardiovascular risk in the mother. Moreover, fetal exposure to hypertension and diabetes during pregnancy can program hypertension and cardiovascular disease in the offspring. Transgenerational transmission of programmed cardiovascular risk highlights the importance of understanding the mechanisms that link complications during pregnancy with later hypertension in her offspring and subsequent generations. However, experimental studies are needed to investigate the cause and effect of increased blood pressure in the mother following a complicated pregnancy and provide insight into the development of preventative measures that may improve the long-term cardiovascular health of women and their offspring.

Cytokine levels in gestational diabetes mellitus: a systematic review of the literature

PROBLEM

Gestational diabetes mellitus (GDM) is an inflammatory condition that involves unbalanced cytokine production. We carried out a systematic review on the relationship between GDM and maternal circulating levels of cytokines in the 2nd/3rd trimesters.

METHOD OF STUDY

Three electronic databases (MEDLINE, EMBASE and LILACS), were searched. Duplicate study selection, extraction and quality assessment was performed.

RESULTS

Twenty-two studies with 1982 participants reporting levels of 9 cytokines (IL-1B, IL-2, IL-6, IL-10, IL-13, IL-18, IFN-G, TGF-B and TNF-A) were included. Most studies differed considerably in selection criteria, sampling and assay methods and in reporting their results. Consequently, only two studies could be pooled: TNF-A concentration was slightly higher in GDM than in control patients, although not significant (WMD=0.45, 95% CI -0.34-1.23).

CONCLUSIONS

New studies with well-defined, more homogeneous methodological parameters are needed to detect whether there are significant differences in circulating levels of cytokines in patients with GDM.