Postpartum development of endothelial dysfunction and oxidative stress markers in women with previous gestational diabetes mellitus

BACKGROUND

Relationships between adhesion molecules (AM), oxidative stress, gestational diabetes mellitus (GDM) and future development of type 2 diabetes mellitus are unclear.

AIM

We investigated AM and oxidant/antioxidant markers in women with previous history of GDM.

SUBJECTS AND METHODS

Postpartum women with GDM (cases; n = 41) and healthy women (controls; n = 21) had clinical and laboratory variables measured, including indicators of vascular damage (ICAM-1, VCAM-1 and E-selectin), oxidative stress (LPO, GSH and GST) and antioxidant markers (catalase, SOD, GPX and TAC).

RESULTS

Previous GDM versus control women presented higher body mass index: 27.4 ± 5.6 versus 23.9 ± 3.6 (p = 0.013); waist circumference: 85.2 ± 12.9 versus 77.5 ± 9.0 (p = 0.017); MetS (WHO definition): 14.6 versus 0 % (p = 0.012); MetS (NCEP-ATPIII definition): 22 versus 0 % (p = 0.002); low HDL: 36.6 versus 9.5 % (p = 0.024); fasting glucose (mmol/L): 5.4 ± 0.6 versus 4.9 ± 0.2 (p < 0.001); glucose 120 min (mg/dL): 105.0 ± 30.2 versus 85.1 ± 14.2 (p = 0.007); fasting insulin (μU/mL): 13.4 ± 8.1 versus 8.4 ± 4.3 (p = 0.004); HOMA index: 3.3 ± 2.3 versus 1.8 ± 1.0 (p = 0.002); HbA1c (%/mmol/mol): 5.4 ± 0.2 versus 5.2 ± 0.2/36 ± 1.4 versus 33 ± 1.4 (p = 0.021); uric acid (mg/dL): 4.1 ± 1 versus 3.5 ± 0.6 (p = 0.009); catalase (nmol/min/mL): 38.7 ± 15.6 versus 28.9 ± 11.1 (p = 0.013). There were no significant differences in hypertension prevalence, lipid fractions, albumin/creatinine ratio and AM.

CONCLUSIONS

Women with previous GDM have high catalase levels which correlate positively with glucose intolerance, indicating the potential effect of oxidative stress on postpartum dysglycemic status.

Endotoxin increase after fat overload is related to postprandial hypertriglyceridemia in morbidly obese patients

The low-grade inflammation observed in obesity has been associated with a high-fat diet, though this relation is not fully understood. Bacterial endotoxin, produced by gut microbiota, may be the linking factor. However, this has not been confirmed in obese patients. To study the relationship between a high-fat diet and bacterial endotoxin, we analyzed postprandial endotoxemia in morbidly obese patients after a fat overload. The endotoxin levels were determined in serum and the chylomicron fraction at baseline and 3 h after a fat overload in 40 morbidly obese patients and their levels related with the degree of insulin resistance and postprandial hypertriglyceridemia. The morbidly obese patients with the highest postprandial hypertriglyceridemia showed a significant increase in lipopolysaccharide (LPS) levels in serum and the chylomicron fraction after the fat overload. Postprandial chylomicron LPS levels correlated positively with the difference between postprandial triglycerides and baseline triglycerides. There were no significant correlations between C-reactive protein (CRP) and LPS levels. The main variables contributing to serum LPS levels after fat overload were baseline and postprandial triglyceride levels but not glucose or insulin resistance. Additionally, superoxide dismutase activity decreased significantly after the fat overload. Postprandial LPS increase after a fat overload is related to postprandial hypertriglyceridemia but not to degree of insulin resistance in morbidly obese patients.

Assessment of cellular and plasma oxidative stress in SAHS patients before and after continuous positive airway pressure treatment

BACKGROUND

Several indirect techniques have been used for measuring oxidative stress in sleep apnoea-hypopnoea syndrome (SAHS) patients. The purpose of this study was to find out if both, cellular or plasma oxidative stress evaluations, are good estimators to assess oxidative stress in SAHS patients before and after one month's CPAP treatment.

METHODS

The study included 28 SAHS patients requiring CPAP treatment and 15 healthy control subjects. Plasma and serum oxidative stress biomarkers (lipid peroxidation, total antioxidant capacity, and the activities of glutathione peroxidase, glutathione reductase, glutathione s-transferase, catalase and superoxide dismutase) were measured using commercial kits. Cellular oxidative stress biomarkers (mitochondrial membrane potential, intracellular glutathione, superoxide anion, and hydrogen peroxide) were analysed by flow cytometry. The Wilcoxon test for paired samples was used to compare oxidative stress and clinical parameters in patients before and after treatment with CPAP. Relationships in oxidative stress markers between controls and patients were analyzed using the Mann-Whitney U test. The Spearman correlation coefficient was calculated to estimate the linear correlations between variables.

RESULTS

Oxidative stress was notably decreased after CPAP. Before CPAP, SAHS severity positively correlated with hydrogen peroxide levels, while negative correlations were observed between SAHS severity and plasma TAC in patients. Also, plasma glutathione peroxidase activity negatively correlated with cellular superoxide anion, while plasma superoxide dismutase activity positively correlated with intracellular glutathione. After CPAP, plasma TAC and glutathione peroxidase activity negatively correlated with cellular hydrogen peroxide and superoxide anion.

CONCLUSIONS

In conclusion, this study seems to confirm that plasma and cellular assessment reflect, in the same way, the oxidative stress status of the studied patients. Furthermore, plasma total antioxidant capacity as well as cellular hydrogen peroxide levels can be good markers for assessing oxidative stress in SAHS patients.