Role of heme oxygenase in the regulation of the renal hemodynamics in a model of sex-dependent programmed hypertension by maternal diabetes.

Intrauterine programming of cardiovascular and renal function occurs in diabetes because of the adverse maternal environment. Heme oxygenase 1 (HO-1) and -2 (HO-2) exert vasodilatory and antioxidant actions, particularly in conditions of elevated HO-1 expression or deficient nitric oxide levels. We evaluated whether the activity of the heme-HO system is differentially regulated by oxidative stress in the female offspring of diabetic mothers, contributing to the improved cardiovascular function in comparison with males. Diabetes was induced in pregnant rats by a single dose of streptozotocin (STZ, 50 mg/kg ip) in late gestation. Three-month-old male offspring from diabetic mothers (MODs) exhibited higher blood pressure (BP), higher renal vascular resistance (RVR), worse endothelium-dependent response to acetylcholine (ACH), and an increased constrictor response to phenylephrine (PHE) compared with those in age-matched female offspring of diabetic mothers (FODs), which were abolished by chronic tempol (1 mM) treatment. In anesthetized animals, stannous mesoporphyrin (SnMP; 40 µmol/kg iv) administration, to inhibit HO activity, increased RVR in FODs and reduced glomerular filtration rate (GFR) in MODs, without altering these parameters in control animals. When compared with MODs, FODs showed lower nitrotirosyne levels and higher HO-1 protein expression in renal homogenates. Indeed, chronic treatment with tempol in MODs prevented elevations in nitrotyrosine levels and the acute renal hemodynamics response to SnMP. Then, maternal diabetes results in sex-specific hypertension and renal alterations associated with oxidative stress mainly in adult male offspring, which are reduced in the female offspring by elevation in HO-1 expression and lower oxidative stress levels.

Lactonase activity and status of paraoxonase 1 and oxidative stress in neonates of women with gestational diabetes mellitus.

BACKGROUND: The level and lactonase activity of paraoxonase 1 (PON1) and their association with PON1 genetic variants and oxidative stress are unclear in neonates of women with gestational diabetes mellitus (GDM). METHODS: This study included 362 neonates of women with GDM and 302 control neonates. The level, lactonase activity, normalized lactonase activity (NLA), and genetic polymorphisms of PON1, serum total oxidant status (TOS), total antioxidant capacity (TAC), and malondialdehyde (MDA) were analyzed. RESULTS: The neonates of the women with GDM had significantly higher levels, lactonase activity, and NLA of PON1, higher TOS, TAC, and MDA concentrations, and relatively higher oxidative stress index than those of the control neonates. The PON1 -108C → T variation decreased the lactonase activity, level, and NLA of PON1, while the PON1 192Q → R variation decreased the PON1 NLA in a genotype-dependent manner in the two groups. Multivariable regression analysis revealed the PON1 -108C/T or 192Q/R variation, apolipoprotein (apo)A1, or apoB as significant predictors of the level, lactonase activity, and NLA of PON1. CONCLUSIONS: The lactonase activity, level, and NLA of PON1 were increased in the neonates of women with GDM. The PON1 genetic variants, abnormalities in lipoproteins, and increased oxidative stress may be associated with these changes. IMPACT: This is the first study to report the elevated level, lactonase activity, and NLA of PON1 in the neonates of women with GDM. These neonates also exhibited increased oxidative stress and an adverse glycolipid metabolic profile. We further established that the -108C/T and/or 192Q/R genetic variants of the PON1 gene, abnormalities in lipoprotein metabolism, and/or increased oxidative stress had noticeable influences on the level and activities of PON1. Whether these changes potentially cause metabolic disorders later in life remains to be determined. Therefore, the neonates born to women with GDM require further clinical follow-ups.

Sex hormone-binding globulin regulates the activity of the ERK pathway in the placentas of patients with gestational diabetes mellitus.

The sex hormone-binding globulin (SHBG) is involved in the onset and progression of insulin resistance and metabolic syndromes, with its expression downregulated in the placental tissues of patients with gestational diabetes mellitus (GDM). However, the underlying mechanisms for these effects remain unclear. In this study, we enrolled an equal number (30) of GDM and non-GDM puerperae who underwent cesarean section at Shengjing Hospital. After due approval by the ethics committee, the expression levels of SHBG and extracellular-signal-regulated kinase (ERK) pathway markers in the placental tissues of these individuals were measured via reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assays. The correlation analysis of these genes revealed that the expression of SHBG in placental tissues was downregulated and negatively correlated with the expression of ERK pathway markers, which were upregulated in placental tissues. Further investigations using the HTR-8/SVneo trophoblast cell line revealed that the trophoblasts with small interfering RNA (siRNA)-silenced SHBG expression displayed increased mRNA and protein expression levels of ERK pathway markers, as well as reduced apoptosis and enhanced proliferation. In contrast, trophoblasts with high SHBG expression showed a downregulated expression of ERK pathway markers, increased apoptosis, reduced proliferation, and a shorter S phase. Therefore, we believe that SHBG may participate in the onset of insulin resistance and GDM by regulating the activity of the ERK pathway.

Blunted Cardiac AMPK Response is Associated with Susceptibility to Ischemia/Reperfusion in Male Offspring of Gestational Diabetic Rats.

BACKGROUND/AIMS: Gestational diabetes mellitus (GDM) is closely associated with early perinatal complications and long-term health problems, such as cardiovascular disease, in offspring. AMP-activated protein kinase (AMPK) is cardioprotective, particularly in the treatment of ischemia/reperfusion (I/R). However, whether GDM programs offspring susceptibility to cardiac I/R and the involvement of AMPK remain unclear. METHODS: Streptozotocin was administered to rats during mid pregnancy; the postpartum maternal metabolome was assessed by chromatography-mass spectrometry (GC-MS). Male offspring were subjected to body composition scanning followed by ex vivo global I/R. Cardiac signaling was determined by Western blotting. RESULTS: The body weights (BWs) of the GDM male offspring were significantly heavier than those of the control group from the age of 8 weeks; the heart weights (HWs) and HW/BW were also increased in the GDM group compared to the control group. The ex vivo post-I/R cardiac contractile function recovery was significantly compromised in the GDM male offspring. The phosphorylation of AMPK and ACC was elevated by ex vivo I/R in both groups, but to a significantly lesser extent in the GDM group. CONCLUSION: GDM male offspring rats have higher risks of overgrowth and intolerance to cardiac I/R, which may be due to a compromised AMPK signaling pathway.

Seasonality, temperature and pregnancy oral glucose tolerance test results in Australia.

BACKGROUND: The oral glucose-tolerance test (OGTT) is currently the standard method for diagnosis of gestational diabetes (GDM). We conducted a post hoc analysis using the Australian Hyperglycemia and Adverse Pregnancy Outcome (HAPO) data to determine seasonal variations in OGTT results, the consequent prevalence of GDM, and association with select perinatal parameters. METHOD: Women enrolled in the Australian HAPO study sites (Brisbane and Newcastle) from 2001 to 2006 were included if OGTT results between 24 to 32 weeks gestation were available (n = 2120). Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, HbA1c, HOMA-IR, and umbilical cord C-peptide and glucose values were categorized by season and correlated to monthly temperature records from the Australian Bureau of Meteorology for Brisbane and Newcastle. GDM was defined post hoc using the IADPSG/WHO criteria. RESULTS: Small but significant (p <  0.01 on ANOVA) elevations in fasting glucose (+ 0.12 mM), HbA1c (+ 0.09%), and HOMA-IR (+ 0.88 units) were observed during the winter months. Conversely, higher 1-h (+ 0.19 mM) and 2-h (+ 0.33 mM) post-load glucose values (both p <  0.01) were observed during the summer months. The correlations between fasting glucose, 1-h glucose, 2-h glucose, and HbA1c with average monthly temperatures confirmed this trend, with positive Pearson's correlations between 1-h and 2-h glucose with increasing average monthly temperatures, and negative correlations with fasting glucose and HbA1c. Further, umbilical cord C-peptide and glucose displayed negative Pearson's correlation with average monthly temperature, aligned with trends seen in the fasting plasma glucose. Overall prevalence of GDM did not display significant seasonal variations due to the opposing trends seen in the fasting versus 1-h and 2-h post-load values. CONCLUSION: A significant winter increase was observed for fasting plasma glucose, HbA1c, and HOMA-IR, which contrasted with changes in 1-h and 2-h post-load venous plasma glucose values. Interestingly, umbilical cord C-peptide and glucose displayed similar trends to that of the fasting plasma glucose. While overall prevalence of GDM did not vary significantly by seasons, this study illustrates that seasonality is indeed an additional factor when interpreting OGTT results for the diagnosis of GDM and provides new direction for future research into the seasonal adjustment of OGTT results.

Increased Alkaline Phosphatase in Cord Blood of Obese Diabetic Mothers Is Associated to Polyunstaurated Fatty Acid Levels.

INTRODUCTION: Recent studies indicate that alkaline phosphatase (ALP) may affect expression and activity of fatty acid (FA) transport proteins in placenta and other tissues. OBJECTIVE: To evaluate if disturbed FA profile in offspring of gestational diabetes mellitus (GDM) with different maternal pregestational weight could be related to maternal or neonatal ALP. METHODS: Prospective observational study of pregnant women recruited in the third trimester (25 controls, 23 lean-GDM, 20 obese-GDM). Fetal ultrasound was performed. At delivery, FAs were analyzed in placenta, maternal, and venous cord blood. Western blotting analysis of lipid carriers was performed in placenta. RESULTS: Newborns from obese-GDM tended to higher birthweight (p = 0.059) than those from both lean-GDM and controls. ALP in maternal blood tended to be lower in GDM (p = 0.170) while increased significantly in cord blood of obese-GDM with respect to controls (p = 0.039). Saturated FA percentages in cord blood were significantly higher (p < 0.000), while polyunsaturated FA (PUFA) percentages were lower (p = 0.003) in both GDM, which could be due to a lower expression of major family domain 2a receptor (MFSD2a) in the placenta. Plasma ALP in the offspring of obese-GDM was inversely associated to cord essential PUFAs (ß = -6.18, p = 0.005) and to placental MFSD2a (ß = -38.46, p = 0.014). CONCLUSIONS: Cord PUFA and placental MFSD2a are decreased in both lean and obese-GDM pregnancies. Higher ALP in cord blood of obese-GDM could play a role in the FA levels in these pregnancies.

Higher level of GGT during mid-pregnancy is associated with increased risk of gestational diabetes mellitus.

OBJECTIVE: This study was to explore the link between gamma-glutamyl transferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST) levels during early-middle pregnancy and subsequent risk of gestational diabetes mellitus (GDM). METHODS: In a prospective cohort study, pregnant women enrolled prior to 16 weeks of gestation were followed up until delivery. GGT, AST and ALT levels were tested during weeks 14-18 of gestation and oral glucose tolerance test was conducted during 24-28 weeks to screen GDM. RESULTS: The GDM rate was 8.1% (122/1512). Mean GGT level was higher in GDM than non-GDM women (18.7 ± 13.0 vs 14.5 ± 7.0, P < .001). The higher GGT level was 26.9~74.0 U/L, which was significantly associated with increased risk of GDM. The adjusted RR (95% CI) comparing higher GGT level versus lower was 5.40 (3.36-8.68). No significant correlation was found between ALT or AST levels and the risk of GDM. CONCLUSIONS: The results suggest that pregnant women with higher serum GGT during early-middle pregnancy have higher risk of developing GDM. A GGT level >26.9 U/L may indicate an increased risk of developing GDM later and should be further concerned.

Activity and distribution of plasma platelet-activating factor acetylhydrolase in women with gestational diabetes mellitus and their neonates.

BACKGROUND: Abnormal activity and distribution of plasma platelet-activating factor acetylhydrolase (PAF-AH) are associated with chronic inflammatory status. In this study, we investigate the activity and distribution of plasma PAF-AH and their association with metabolic components in mothers with gestational diabetes mellitus (GDM) and in their neonates. METHODS: Based on the International Association of Diabetes Pregnancy Study Group criteria, we performed a case-controlled study of 101 women with GDM, 98 women with uncomplicated pregnancies, 142 neonates of mothers with GDM and 121 neonates of mothers with uncomplicated pregnancies. Plasma PAF-AH, high-density lipoprotein (HDL)-associated PAF-AH (H-PAF-AH) and apolipoprotein (apo) B-containing lipoprotein-associated PAF-AH (apoB-PAF-AH) activities were measured using the trichloroacetic acid precipitation procedure with PAF C-16 as a substrate. RESULTS: The plasma PAF-AH and apoB-PAF-AH activities, triglyceride (TG) levels, atherogenic index and TG/HDL-C ratio were increased, and the H-PAF-AH proportions were decreased in the mothers with GDM compared with the control mothers (p < 0.05). Multivariate regression analyses demonstrated that the apoB and TG levels were significant predictors of plasma PAF-AH or apoB-PAF-AH activities, while the low-density lipoprotein-cholesterol levels, weight gain during pregnancy and age were associated with H-PAF-AH activities. The neonates of mothers with GDM had higher plasma insulin and glucose concentrations (p < 0.05) and tended to exhibit increased serum apoB levels (p = 0.062) compared with the neonates of mothers with uncomplicated pregnancies. CONCLUSIONS: The mothers with GDM presented with a state of chronic inflammation, and these mothers and their neonates also exhibited unfavourable metabolic profiles in terms of glucose and lipids. Copyright © 2016 John Wiley & Sons, Ltd.

Association of downregulated HDAC 2 with the impaired mitochondrial function and cytokine secretion in the monocytes/macrophages from gestational diabetes mellitus patients.

Gestational diabetes mellitus (GDM) is associated with an increased risk of type 2 diabetes (T2DM) and cardiovascular diseases in later life, yet with underlying mechanisms unclear. The present study was to explore the association of upregulated histone deacetylase 2 (HDAC 2) with the impaired mitochondrial function and the cytokine secretion in the monocytes/macrophages from GDM patients. In this study, we examined the mitochondrial function, proinflamatory cytokine secretion and the HDAC 2 level in the serum or in the monocytes/macrophages from GDM patients, investigated the influence by HDAC 2 inhibitor, AR-42 (N-hydroxy-4-[[(2S)-3-methyl-2-phenylbutanoyl]amino]benzamide), on the mitochondrial function and cytokine secretion in the isolated GDM monocytes/macrophages. Results demonstrated an increased mitochondria size, mitochondrial superoxide and reactive oxygen species (ROS) production, and an undermined mitochondria membrane potential (MMP) in the GDM monocytes/macrophages. And the serum levels of interleukin (IL)-1ß, tumor necrosis factor (TNF)-α and IL-6 were also markedly higher in the GDM pregnancies, while the expression and activity of HDAC 2 was downregulated. Moreover, AR-42-mediated HDAC 2 inhibition in vitro contributed to the impaired mitochondrial function and the proinflamatory cytokine secretion. In conclusion, this study suggests an association of the impaired mitochondrial function and the promoted proinflamatory cytokine secretion with the reduced HDAC 2 activity in GDM. These findings may present HDAC 2 as a target for GDM treatment.

Gestational diabetes mellitus impairs fetal endothelial cell functions through a mechanism involving microRNA-101 and histone methyltransferase enhancer of zester homolog-2.

OBJECTIVE: Gestational diabetes mellitus (GDM) produces fetal hyperglycemia with increased lifelong risks for the exposed offspring of cardiovascular and other diseases. Epigenetic mechanisms induce long-term gene expression changes in response to in utero environmental perturbations. Moreover, microRNAs (miRs) control the function of endothelial cells (ECs) under physiological and pathological conditions and can target the epigenetic machinery. We investigated the functional and expressional effect of GDM on human fetal ECs of the umbilical cord vein (HUVECs). We focused on miR-101 and 1 of its targets, enhancer of zester homolog-2 (EZH2), which trimethylates the lysine 27 of histone 3, thus repressing gene transcription. EZH2 exists as isoforms α and ß. APPROACH AND RESULTS: HUVECs were prepared from GDM or healthy pregnancies and tested in apoptosis, migration, and Matrigel assays. GDM-HUVECs demonstrated decreased functional capacities, increased miR-101 expression, and reduced EZH2- ß and trimethylation of histone H3 on lysine 27 levels. MiR-101 inhibition increased EZH2 expression and improved GDM-HUVEC function. Healthy HUVECs were exposed to high or normal d-glucose concentration for 48 hours and then tested for miR-101 and EZH2 expression. Similar to GDM, high glucose increased miR-101 expression. Chromatin immunoprecipitation using an antibody for EZH2 followed by polymerase chain reaction analyses for miR-101 gene promoter regions showed that both GDM and high glucose concentration reduced EZH2 binding to the miR-101 locus in HUVECs. Moreover, EZH2-ß overexpression inhibited miR-101 promoter activity in HUVECs. CONCLUSIONS: GDM impairs HUVEC function via miR-101 upregulation. EZH2 is both a transcriptional inhibitor and a target gene of miR-101 in HUVECs, and it contributes to some of the miR-101-induced defects of GDM-HUVECs.

Cord serum dipeptidyl-peptidase 4 activity in gestational diabetes.

BACKGROUND: Tissue-specific dipeptidyl-peptidase 4 (DPP4) dysregulation has been described in adults with diabetes mellitus. The DPP4 -incretin system has not been studied in foetal life. In this study, DPP4 activity and glucagon-like peptide-1 (GLP-1) levels were assessed in cord blood of neonates born to women with gestational diabetes mellitus (GDM) and nondiabetic controls. MATERIAL AND METHODS: This study has been conducted in two Hungarian and one Austrian centres. PATIENTS: A total of 568 pregnant women were enrolled in the study after their OGTT between the 24th and 28th gestational week. Cord blood samplings with DPP4 activity and GLP-1 level measurements were possible in 270 (DPP4: 159 control, 111 GDM) and 112 (GLP-1: 72 control, 40 GDM) cases. OGTT (24-28th gestational week) and cord blood sampling at delivery were performed. Cord serum DPP4 activity was determined in a continuous monitoring microplate-based kinetic assay, and cord plasma GLP-1 was measured using a fluorescence ELISA method. RESULTS: Cord serum DPP4 activity was lower in GDM [mean (95% CI): 28.07 U/L (26.32-29.82 U/L)] than in controls [31.61 U/L (29.93-33.29 U/L), MWU P = 0.0015]. Cord plasma active GLP-1 levels were close to the lower detection limit and were not altered in GDM (control: mean = 3.43 pM, 95% CI: 3.04-3.82 pM, GDM: mean = 3.61 pM, 95% CI: 2.96-4.28 pM - MWU test P = 0.6). CONCLUSIONS: Decreased cord serum DPP4 activity in gestational diabetes mellitus might be the result of an adaptive foetal response or an early dysregulation in the entero-insular axis with consequences beyond the incretin system. Cord plasma GLP-1 levels may reflect the missing oral intake with a limited glucose sensing of L cells via the circulation in foetal life.

GCK monogenic diabetes and gestational diabetes: possible diagnosis on clinical grounds.

AIM: To determine if the previously published clinical criteria for identifying glucokinase monogenic diabetes [GCK gene mutation in maturity-onset diabetes of the young (GCK-MODY)], an elevated antenatal fasting blood glucose of 5.5-8.0 mmol/l, an increment of < 4.6 mmol/l at 2 h in an oral glucose tolerance test and slim are applicable in a large multi-ethnic cohort of women with gestational diabetes. METHODS: We analysed de-identified data from all women with gestational diabetes, diagnosed using the Australasian Diabetes in Pregnancy Society (1998) Australian criteria at our institution between 1993 and 2013, making comparisons among those with complete antenatal data including: diagnostic oral glucose tolerance test results meeting the above criteria; pregestational BMI; birth outcomes; and postpartum oral glucose tolerance test data. We categorized these women into two groups: Group A1 had a BMI ≤ 21 kg/m(2) and Group A2 had a BMI > 21 kg/m(2) and < 25 kg/m(2). RESULTS: Of the 302 women meeting the study entry criteria, we had complete data including a postpartum oral glucose tolerance test result for 171 women: 54 in Group A1 and 117 in Group A2. Ethnicity was significantly different between the groups. The oral glucose tolerance test and postpartum HbA1c results identified few women ( < 14%) in Group A1 and Group A2 who still had 'possible GCK-MODY'. CONCLUSIONS: Our findings indicate that previously recommended clinical criteria for the identification of women likely to have GCK-MODY lack specificity in a cohort of women with multi-ethnic backgrounds. Using these criteria to select women for testing for GCK-MODY in pregnancy would therefore be costly and is likely to yield few women positive for this condition.

Relationship between a lipoprotein lipase gene polymorphism in placental tissue and insulin resistance in patients with gestational diabetes mellitus.

The aim of this study was to investigate the relationship between a lipoprotein lipase (LPL) gene polymorphism in placental tissue and insulin resistance (IR) in patients with gestational diabetes mellitus. Using polymerase chain reaction-restriction enzyme fragment length polymorphism (PCR-RFLP) analysis, the LPL HindIII RFLP was examined in the placental tissue of 110 patients with gestational diabetes mellitus (observation group) and 110 women with normal gestation (control group). The relationships between fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting insulin (FINS), cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), body mass index (BMI), and IR indices and the LPL polymorphism in the two study groups and their offspring were determined. The frequency of the H+ allele was significantly higher in the observation group than in the controls (P < 0.05). There were statistically significant differences in the observation group between the FPG, PPG, LDL, TC, TG, HDL, BMI, FINS, and IR indices of the H+H+ group and those of the non H+H+ type patients (P < 0.05). Correlation analysis showed that the LPL gene polymorphism was positively related to IR. There were statistically significant differences between HDL, BMI, and IR indices between the two study groups (P < 0.05). In conclusion, the LPL gene polymorphism was determined to be the main factor related to IR in women with gestational diabetes, and was also found to be related to the IR of their offspring.

The association of endothelial nitric oxide synthase gene G894T polymorphism and serum nitric oxide concentration with microalbuminuria in patients with gestational diabetes.

AIM: Gestational diabetes mellitus (GDM) is a glucose intolerant condition that affects 14% of all pregnancies. Diabetes mellitus (DM) occurs in 30 - 70% of patients with GDM after delivery. DM and GDM are associated with structural and functional deterioration of the renovascular system. Our aim is to investigate the association Glu- 298Asp polymorphism of the endothelial nitric oxide synthase (eNOS) gene with serum nitric oxide levels and microalbuminuria in patients with GDM and healthy pregnancies. MATERIAL AND METHODS: Serum nitric oxide (NO) levels, urinary excretion of albumin and Glu298Asp polymorphism of the eNOS gene were analyzed in 68 patients with GDM and 73 healthy controls. High performance liquid chromatography (HPLC-Griess) method was used to analyze serum NO levels. Microalbuminuria was evaluated by rate nephelometry method. The Glu298Asp polymorphism of the eNOS gene was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). RESULTS: Nitric oxide, glucose, creatinine, and microalbuminuria were significantly different between the patients and the control subjects (p = 0.001, p = 0.001, p = 0.002, and p = 0.005, respectively). There was a significant difference between groups in terms of the ratio of GG/GT+TT of eNOS gene Glu- 298Asp (p = 0.02). The patients with GT+TT genotype had significantly higher microalbuminuria levels and lower NO concentrations (22.16 vs. 9.51, p = 0.005, and 10.56 vs. 12.73, p = 0.021, respectively). The presence of T allele of eNOS gene is an independent predictor of microalbuminuria (OR: 2.346, 95% confidence interval: 1.247 - 5.238, p = 0.02) as well as serum glucose and NO concentration. CONCLUSION: The G894T polymorphism of eNOS gene and decreased NO concentration seem to be independent predictors of increased urinary excretion of albumin in patients with GDM. Determining the frequency of eNOS gene G894T polymorphism may help to identify pregnancies at increased risk of microalbuminuria.

Inherited catalase deficiency: is it benign or a factor in various age related disorders?

Hydrogen peroxide was - and is still - considered toxic for a wide range of living organisms. Oxidative stress occurs when there is an excess of pro-oxidants over antioxidants and it has been implicated in several diseases. Catalase is involved in hydrogen peroxide catabolism and is important in defense against oxidative stress. Acatalasemia means the inherited near-total deficiency of catalase activity, usually in reference to red cell catalase. Acatalasemia was thought at first to be an asymptotic disorder. In the absence of catalase, neither the Japanese, or Hungarian acatalasemics nor acatalasemic mice had significantly increased blood glutathione peroxidase activity. In animal models, catalase deficient tissues show much slower rates of removal of extracellular hydrogen peroxide. In catalase knock-out mice, a decreased hydrogen peroxide removing capacity and increased reactive oxygen species formation were reported. Hydrogen peroxide may cause methemoglobinemia in patients with catalase deficiency. During anesthesia for a Japanese acatalasemic patient the disinfection with hydrogen peroxide solution caused severe methemoglobinemia. Patients with inherited catalase deficiency, who are treated with uric acid oxidase (rasburicase) may experience very high concentrations of hydrogen peroxide and may suffer from methemoglobinemia and hemolysis. The high (18.5%) prevalence of diabetes mellitus in inherited catalase deficient individuals and the earlier (10 years) manifestation of the disease may be attributed to the oxidative damage of oxidant sensitive, insulin producing pancreatic beta-cells. Ninety-seven of 114 acatalasemics had diseases related to oxidative stress and aging. The oxidative stress due to catalase deficiency could contribute to the manifestation of diabetes while for the other diseases it may be one of the factors in their causations. In summary, inherited catalase deficiency is associated with clinical features, pathologic laboratory test results, age and oxidative stress related disorders. Rather than considering it a benign condition, it should be considered as a complicating condition for aging and oxidative stress.

Ethnic variation in the activity of lipid desaturases and their relationships with cardiovascular risk factors in control women and an at-risk group with previous gestational diabetes mellitus: a cross-sectional study.

BACKGROUND: Lipid desaturase enzymes mediate the metabolism of fatty acids to long chain polyunsaturated fatty acids and their activities are related to metabolic risk factors for Type 2 diabetes (T2DM) and coronary heart disease (CHD). There are marked ethnic differences in risks of CHD and T2DM but little is known about ethnic differences in desaturase activities. METHODS: Samples from a study of CVD risk in women with previous gestational diabetes were analysed for percentage fatty acids in plasma free fatty acid, triglyceride, cholesterol ester and phospholipid pools for 89 white European, 53 African Caribbean and 56 Asian Indian women. The fatty acid desaturase activities, stearoyl-CoA desaturase (SCD, calculated separately for C16 and C18 fatty acids), delta 6 desaturase (D6D) and delta 5 desaturase (D5D) were estimated from precursor-to-product ratios and their relationships with adiposity, blood pressure, cholesterol, triglycerides, HDL cholesterol and insulin sensitivity explored. Ethnic differences in desaturase activities independent of ethnic variation in risk factor correlates of desaturase activities were then identified. RESULTS: There was significant ethnic variation in age, BMI, waist circumference, blood pressure, serum triglycerides and HDL cholesterol concentrations and insulin resistance. Desaturase activities showed significant correlations, independent of ethnicity, with BMI, waist circumference, triglycerides and HDL cholesterol. Independent of ethnic variation in BMI, waist circumference, triglycerides and HDL cholesterol, SCD-16 activity, calculated from each of the four lipid pools measured, was 18-35 percent higher in white Europeans than in African Caribbeans or Asian Indians (all p < 0.001). Similar, though less consistent differences were apparent for SCD-18 activity. Also independently of risk factor variation, but specifically when calculated from the cholesterol ester and phospholipid, pools, D6D activity was significantly lower in Asian Indians, and D5D activity higher in African Caribbeans. CONCLUSIONS: Significant ethnic differences exist in desaturase activities, independently of ethnic variation in other risk factors. These characteristics did not accord with higher risk of T2DM among African Caribbeans and Asian Indians nor with lower risk of CHD among African Caribbeans but did accord with the higher risk of CHD in Asian Indians.

Salivary exoglycosidases in gestational diabetes .

INTRODUCTION: As exoglycosidases have been described as potential markers of salivary gland pathology, we decided to check the possibility of the use of these enzymes in the detection of salivary gland involvement in gestational diabetes. MATERIALS AND METHODS: For this purpose diabetic pregnant women were compared to pregnant and non-pregnant healthy women. The activities of total HEX as well as GLU in the saliva were determined in duplicate according to Marciniak et al. The activities of GAL, FUC, and MAN in the saliva were determined in duplicate according to Zwierz et al. RESULTS: It was found that the specific activities of exoglycosidases in the saliva of diabetic pregnant women significantly increased in comparison to healthy pregnant and non-pregnant women. CONCLUSION: Increased specific activity of exoglycosidases suggests that gestational diabetes provokes structural/functional alterations in salivary glands and changes in the salivary glycoconjugates metabolism.

A low-protein diet during pregnancy alters glucose metabolism and insulin secretion.

In pancreatic islets, glucose metabolism is a key process for insulin secretion, and pregnancy requires an increase in insulin secretion to compensate for the typical insulin resistance at the end of this period. Because a low-protein diet decreases insulin secretion, this type of diet could impair glucose homeostasis, leading to gestational diabetes. In pancreatic islets, we investigated GLUT2, glucokinase and hexokinase expression patterns as well as glucose uptake, utilization and oxidation rates. Adult control non-pregnant (CNP) and control pregnant (CP) rats were fed a normal protein diet (17%), whereas low-protein non-pregnant (LPNP) and low-protein pregnant (LPP) rats were fed a low-protein diet (6%) from days 1 to 15 of pregnancy. The insulin secretion in 2.8 mmol l(-1) of glucose was higher in islets from LPP rats than that in islets from CP, CNP and LPNP rats. Maximal insulin release was obtained at 8.3 and 16.7 mmol l(-1) of glucose in LPP and CP groups, respectively. The glucose dose-response curve from LPNP group was shifted to the right in relation to the CNP group. In the CP group, the concentration-response curve to glucose was shifted to the left compared with the CNP group. The LPP groups exhibited an "inverted U-shape" dose-response curve. The alterations in the GLUT2, glucokinase and hexokinase expression patterns neither impaired glucose metabolism nor correlated with glucose islet sensitivity, suggesting that ß-cell sensitivity to glucose requires secondary events other than the observed metabolic/molecular events.

Can serum gamma-glutamyltransferase levels be useful at diagnosing gestational diabetes mellitus?

OBJECTIVE: The aim of this study was to evaluate plasma gamma-glutamyltransferase (GGT) in gestational diabetes mellitus (GDM) in pregnant women at oral glucose tolerance test (OGTT) and the diagnosis of GDM and to explore whether this activity is associated with metabolic parameters. METHOD: This prospective control study included 37 women with GDM and 42 women with normal glucose tolerance in pregnancy (control group). In the study group (GDM), blood was taken for analyzing 100 g OGTT from women who have abnormal 50 g glucose challenge test (GCT). RESULTS: Compared with the controls, the GDM group had significantly higher mean values for serum fasting glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), triglyceride and GGT. Within the GDM group, GGT levels were only negatively correlated with high-density lipoprotein (r = -0.41, p = 0.01). GGT was determined to be an independent metabolic parameter for GDM. While performing analyses receiver operational curve analysis, GGT cutoff set was set at 16 IU/L, the sensitivity was calculated as 86%, and specificity was as 37%. CONCLUSION: The increase at GGT level is an independent risk factor for GDM and identified as high-risk women for diagnosis of GDM.

Maternal diabetes-mediated RORA suppression in mice contributes to autism-like offspring through inhibition of aromatase.

Retinoic acid-related orphan receptor alpha (RORA) suppression is associated with autism spectrum disorder (ASD) development, although the mechanism remains unclear. In this study, we aim to investigate the potential effect and mechanisms of RORA suppression on autism-like behavior (ALB) through maternal diabetes-mediated mouse model. Our in vitro study in human neural progenitor cells shows that transient hyperglycemia induces persistent RORA suppression through oxidative stress-mediated epigenetic modifications and subsequent dissociation of octamer-binding transcription factor 3/4 from the RORA promoter, subsequently suppressing the expression of aromatase and superoxide dismutase 2. The in vivo mouse study shows that prenatal RORA deficiency in neuron-specific RORA null mice mimics maternal diabetes-mediated ALB; postnatal RORA expression in the amygdala ameliorates, while postnatal RORA knockdown mimics, maternal diabetes-mediated ALB in offspring. In addition, RORA mRNA levels in peripheral blood mononuclear cells decrease to 34.2% in ASD patients (n = 121) compared to the typically developing group (n = 118), and the related Receiver Operating Characteristic curve shows good sensitivity and specificity with a calculated 84.1% of Area Under the Curve for ASD diagnosis. We conclude that maternal diabetes contributes to ALB in offspring through suppression of RORA and aromatase, RORA expression in PBMC could be a potential marker for ASD screening.