Prematurity and congenital malformations differ according to the type of pregestational diabetes

BACKGROUND

Diabetes mellitus (DM) is the most common metabolic disorder in pregnancy. Women with Type 2 DM seems to have no better perinatal outcomes than those with Type 1 DM.

METHODS

Single-center prospective cohort observational study. Pregnant women with diabetes (141 with Type 1 DM and 124 with Type 2 DM) that were followed in the university hospital between 2009 and 2021 were included in this study. Clinical data and obstetric and perinatal outcomes were collected.

RESULTS

As expected, women with Type 1 DM were younger and had a longer duration of diabetes than women with Type 2 DM. Obesity and chronic hypertension were higher in the group of women with Type 2 DM and their value of HbA1c in the second and third trimesters were lower than in Type 1 DM. No differences in prematurity were found, but more extreme prematurity was observed in Type 2 DM, as well as a higher rate of congenital malformations. The frequency of hypoglycemia and the weight of the newborn was higher in Type 1 DM. The maternal independent factors related to the weight of the newborn were: the glycemic control at the third trimester, the weight gain during pregnancy, and pregestational BMI.

CONCLUSIONS

Newborns born to mothers with Type 1 DM were larger and had a higher frequency of hypoglycemia, while congenital malformations and precocious preterm was more associated to Type 2 DM. Metabolic control, weight gain and pregestational weight were important determinants of both obstetric and neonatal complications.

The usefulness of HbA1c in postpartum reclassification of gestational diabetes

To investigate the role of HbA1c in postpartum reclassification of gestational diabetes (GDM) we studied 364 women with GDM attending the postpartum reclassification assessment of their glucose tolerance status. A 75-g oral glucose tolerance test (OGTT) was performed and HbA1c was determined. Diabetes was diagnosed in 12 (3.3%), 7 (1.9%) and 2 (0.6%) women according to the fasting plasma glucose (FPG) and/or the 2-hour OGTT, the FPG alone and HbA1c levels, respectively. The sensitivity and specificity for HbA1c to diagnose diabetes was 16.7% and 100%, respectively, for FPG and OGTT criteria. The combination of a cutoff value of 5.5% for HbA1c and FPG allowed us to identify 95.1% of women with any kind of glucose intolerance. We conclude that in the early postpartum period, the cutoff of 6.5% for HbA1c alone has low sensitivity for the diagnosis of diabetes compared with OGTT, but the combination of FPG and HbA1c at a lower cutoff value is very useful to identify women with any kind of glucose intolerance.

Insulin resistance, low-grade inflammation and type 1 diabetes mellitus

To assess the relationships between insulin resistance and low-grade inflammation in subjects with type 1 diabetes mellitus (T1DM) who do not have clinical macrovascular complications. A total of 120 subjects diagnosed with T1DM 14 years before were evaluated for the following: (1) sex, age, body mass index, waist-to-hip ratio (WHR), blood pressure, smoking, alcohol intake, insulin dose, HbA1c and lipid profile; (2) microvascular complications; (3) plasma concentrations of soluble fractions of tumour necrosis factor-α receptors type 1 and 2, interleukin-6, adiponectin, leptin and high-sensitivity C-reactive protein (hs-CRP); and (4) insulin resistance (estimation of the glucose disposal rate-eGDR). Those subjects with an eGDR below the median of the same sex group were classified as insulin resistant and the others as insulin sensitive. Insulin-resistant men, compared to the insulin-sensitive, had higher WHR (0.89 ± 0.08 vs. 0.83 ± 0.05; P < 0.01), higher systolic [121 (118-125) vs. 114 (108-120) mmHg; P = 0.01] and diastolic [73 (66-80) vs. 67 (70-73) mmHg; P = 0.02] blood pressures, higher HbA1c values [8.7 (8.1-9.9) vs. 7.5 (7.2-8.0) %; P < 0.01] and higher hs-CRP concentrations [1.16 (0.61-3.20) vs. 0.49 (0.31-0.82) mg/dl; P = 0.01], but no other significant differences between groups were found. Insulin-resistant women had higher WHR and HbA1c values, compared to the insulin-sensitive, but they did not have any other differences. In men, hs-CRP correlated significantly with WHR and HbA1c (r = 0.363; P = 0.016 and r = 0.317; P = 0.036, respectively), after adjusting for age, alcohol intake, smoking and microvascular complications. Insulin-resistant men with T1DM have an increase in plasma concentrations of hs-CRP. Central obesity and HbA1c are its main determinants.

Effect of weight loss induced by gastric bypass on proinflammatory interleukin-18, soluble tumour necrosis factor-alpha receptors, C-reactive protein and adiponectin in morbidly obese patients

OBJECTIVE

Interleukin-18 (IL-18) is a potent proinflammatory cytokine whose role in human obesity has recently been suggested. The aim of our study was to analyse in morbidly obese patients undergoing gastric bypass, the relationship of IL-18 with insulin resistance and with proinflammatory cytokines (tumour necrosis factor-alpha receptors, sTNFR), C-reactive protein (CRP) and with adiponectin.

DESIGN

Observational and prospective study.

PATIENTS

Sixty-five morbidly obese patients, aged 45 +/- 8.9 years, were studied before and 12 months after gastric bypass.

MEASUREMENTS

We analysed plasma concentrations of IL-18, sTNFR, CRP and adiponectin.

RESULTS

Plasma concentrations of sTNFR2, IL-18 and CRP were decreased and adiponectin significantly increased after bypass surgery. In the multiple regression analysis, preoperative values of IL-18 remained significantly associated with preoperative triglycerides (beta = 0.47, P = 0.005) and TNFR2 (beta = 0.47, P = 0.004). R(2) for the model = 0.38. Postoperative IL-18 concentrations in the multiple regression analysis were significantly associated with postoperative homeostasis model assessment of insulin resistance (HOMA-IR) (beta = 0.092, P = 0.019) and triglycerides (beta = 0.40, P = 0.036). R(2) for the model = 0.46. IL-18 did not correlate with body mass index, fat mass, fat-free mass or body fat. No relationship was either found between adiponectin and IL-18, TNFR1 and -2 and CRP.

CONCLUSIONS

Massive weight loss induced by gastric bypass reduces IL-18, TNFR2 and CRP. IL-18 might be a marker of the chronic inflammatory process underlying insulin resistance but its lack of association with anthropometric and body composition parameters does not support a major secretion by human adipocytes. IL-18 and sTNFR1 and -2 do not play a main role in the inhibition of the secretion of adiponectin.

Adipose tissue expression of the glycerol channel aquaporin-7 gene is altered in severe obesity but not in type 2 diabetes

CONTEXT

Aquaporin-7 is required for efflux of glycerol from adipocytes and influences whole-body glucose homeostasis in animal studies.

OBJECTIVE

Our objective was to test the hypothesis that AQP7 gene expression levels may be affected by presence of obesity and type 2 diabetes in humans.

DESIGN

The obesity study cohort consisted of 12 lean, 22 nonseverely obese, and 13 severely obese subjects. The type 2 diabetes study cohort consisted of 17 lean and 39 obese type 2 diabetic patients. Circulating levels of plasma soluble proteins monocyte chemoattractant protein-1, TNF receptors 1 and 2, and IL-6 and glycerol were measured. The sc adipose tissue gene expression of AQP7, MCP-1, IL-6, TNFalpha, PPARgamma, and SREBP1c genes was measured by real-time PCR. AQP7 gene mutation analysis was performed.

RESULTS

Severely obese women showed lower AQP7 expression levels compared with lean and nonseverely obese (P < 0.001). Moreover, circulating glycerol concentration was lower in severely obese subjects, but no correlation with AQP7 adipose tissue expression was observed. AQP7 expression was negatively related with proinflammatory genes (for monocyte chemoattractant protein-1, r = -0.203 and P = 0.044; for TNFalpha, r = -0.209 and P = 0.036). Concerning adipogenic factors, AQP7 expression levels were found to be positively determined by PPARgamma mRNA expression levels (r = 0.265; P = 0.012). AQP7 expression did not show differences regarding the presence of type 2 diabetes.

CONCLUSION

Expression of AQP7 is down-regulated in women with severe obesity. The expression of this glycerol channel is not affected by type 2 diabetes.

Lower heart rate variability is associated with higher plasma concentrations of IL-6 in type 1 diabetes

OBJECTIVE

In type 1 diabetes, cardiovascular autonomic neuropathy (CAN) is associated with cardiovascular risk factors related to insulin resistance, which in turn are associated with low-grade systemic inflammation. Reduced heart rate variability (HRV) is considered one of the first indicators of CAN. Since the autonomic nervous system interacts with systemic inflammation, we evaluated CAN to study its possible association with low-grade systemic inflammation.

DESIGN

Cross-sectional study of a group of 120 subjects diagnosed with type 1 diabetes mellitus 14 years before.

METHODS

Information recorded: 1) clinical characteristics: sex, age, body mass index, waist-to-hip ratio (WHR), blood pressure (BP), smoking, alcohol intake, insulin dose, HbA1c, and lipid profile; 2) plasma levels of soluble fractions of tumour necrosis factor alpha receptors 1 and 2, IL-6, and C-reactive protein; 3) insulin resistance by estimation of the glucose disposal rate (eGDR); and 4) tests for CAN: HRV in response to deep breathing (E/I ratio), HRV in response to the Valsalva maneuver, and changes in systolic BP responding to standing.

RESULTS

A significant negative correlation was found between E/I ratio and plasma concentrations of IL-6 (r=-0.244, P=0.032), which remained significant after adjusting for potential confounding factors (age, sex, HbA1c, WHR, diastolic BP, triglycerides, HDL-cholesterol, retinopathy, nephropathy, peripheral neuropathy, insulin dose, and smoking; r=-0.231, P=0.039). No other significant associations were found between inflammation-related proteins, tests for CAN, and eGDR.

CONCLUSIONS

These findings suggest a link between low-grade inflammation and early alterations of CAN in type 1 diabetes and may be of importance in the pathogenesis of CAN and/or its clinical implications.

IL-18: relationship with anthropometry, body composition parameters, leptin and arterial hypertension

OBJECTIVE

Interleukin-18 (IL-18) is a potent pro-inflammatory cytokine with potential atherogenic properties whose role in human obesity has been recently suggested. The aim of our study was to analyze the physiologic distribution of IL-18 among sexes and all decades of the adult life in a healthy population randomly selected and to study its relationship with anthropometric, body composition measurements and leptin concentrations. We also studied the relationship of IL-18 with smoking and arterial hypertension, known risk factors implicated in atherogenesis.

MATERIALS AND METHODS

One hundred and thirty four men and 127 healthy women were included in the study. Plasma concentrations of IL-18 and leptin were determined in all subjects. Body composition was evaluated by bioelectrical impedanciometry.

RESULTS

IL-18 was distributed similarly in men and women and throughout decades. No significant differences were found in IL-18 between obese and normal-weight men and women according to their body mass index and body fat content. Higher IL-18 concentrations were found in subjects with arterial hypertension. In the bivariate correlation analysis only waist to hip ratio correlated weakly with IL-18 in the whole population (r=0.12, p=0.04). In the multiple regression analysis the relationship between IL-18 and waist to hip ratio lost significance after adjusting for age, sex and body mass index. However, IL-18 remained associated with arterial hypertension (adjusted r2=0.25, p=0.023).

CONCLUSIONS

The lack of correlation between IL-18 with anthropometric, body composition variables and leptin in our healthy population argues against a role of this cytokine in obesity. Moreover, our findings suggest the implication of this interleukin in the atherogenic process induced by arterial hypertension.

The tumour necrosis factor (TNF)-alpha system is activated in accordance with pulse pressure in normotensive subjects with type 1 diabetes mellitus

OBJECTIVE

Pulse pressure (PP) and inflammation are important predictors of cardiovascular disease (CVD), even in the normotensive. The age-related increase in PP can be diagnosed up to 20 years earlier in subjects with type 1 diabetes mellitus (T1DM) than in the general population. Some evidence suggests that PP can stimulate inflammation. Our aim was to study the relationship between PP and plasma inflammatory proteins in normotensive subjects with T1DM.

DESIGN

This was a cross-sectional study of a group of normotensive (<140/80 mmHg) subjects diagnosed with T1DM 14 years before. None of them had clinically proven CVD or inflammatory conditions or were on antiplatelet, antihypertensive, anti-inflammatory or lipid-lowering treatment.

METHODS

The following information was recorded: sex, age, body-mass index (BMI), waist-to-hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), PP, mean blood pressure (MBP), smoking, alcohol intake, insulin dose, lipid profile, HbA1c, microvascular complications, and plasma concentrations of soluble receptor types 1 and 2 of tumour necrosis factor (TNF)-alpha (sTNFR1 and sTNFR2, respectively), interleukin-6, C-reactive protein, adiponectin and leptin.

RESULTS

A total of 112 subjects were evaluated (aged 27.4+/-6.6 years, 52.7% women, BMI: 20.4+/-2.7 kg/m2, WHR: 0.82+/-0.09, SBP: 112+/-12 mmHg, DBP: 68+/-9 mmHg, PP: 45+/-9 mmHg, MBP: 82+/-9 mmHg, HbA1c: 8.2% (7.3-9.0%), 41.1% microvascular complications). After adjusting for potential confounders, only inflammatory markers of the TNF-alpha system correlated significantly with PP (Pearson correlation coefficient between sTNFR1 and PP: r = 0.215, P = 0.030; and between PP and sTNFR2: r = 0.238, P = 0.020).

CONCLUSION

In normotensive subjects with T1DM after 14 years of diagnosis, the activation of the TNF-alpha system is positively associated with PP levels. This finding might suggest a pathogenic role of the TNF-alpha system in the development of cardiovascular disease in T1DM.

Diabetic neuropathy is associated with activation of the TNF-alpha system in subjects with type 1 diabetes mellitus

OBJECTIVE

The development of diabetic neuropathy (DN) is predicted by cardiovascular risk factors associated with insulin resistance. As inflammation seems to be implicated in the pathogenesis of insulin resistance, we investigated whether subjects with type 1 diabetes mellitus (T1DM) and DN have an increase in plasma concentrations of inflammatory proteins involved in insulin resistance.

DESIGN

Cross-sectional. Patients One hundred twenty subjects, all diagnosed with T1DM 14 years before.

MEASUREMENTS

(1) Sex, age, body mass index, waist-to-hip ratio (WHR), blood pressure, smoking, alcohol intake, insulin dose, HbA1c and lipid profile; (2) DN (peripheral and cardiac autonomic), retinopathy and nephropathy; (3) plasma concentrations of soluble fractions of tumour necrosis factor alpha receptors 1 and 2 (sTNFR1 and sTNFR2), interleukin-6, high-sensitive C-reactive protein, adiponectin and leptin; and (4) insulin resistance (by way of a mathematical estimation of the glucose disposal rate - eGDR-).

RESULTS

Thirty-six subjects had DN and 84 did not. Subjects with DN received higher insulin doses (57.6 +/- 16.7 vs. 49.2 +/- 15.0 IU/day; P = 0.008) and had higher WHR (0.85 +/- 0.07 vs. 0.81 +/- 0.10; P = 0.007) and HbA1c values (8.5 (7.6-9.6) vs. 7.7 (7.3-8.9)%; P = 0.049) than subjects without DN. They also had higher values of sTNFR1 (2.42 +/- 0.60 vs. 1.96 +/- 0.66 microg/l; P = 0.001) and sTNFR2 (4.73 +/- 1.33 vs. 4.14 +/- 1.09 microg/l; P = 0.015), and were more insulin resistant (eGDR values: 7.28 (5.83-8.03) vs. 8.30 (7.17-9.03) mg kg(-1) min(-1); P = 0.003). The relationship between DN and either sTNFR1 or sTNFR2 remained essentially unchanged after adjusting for several confounders, including glycaemic control, WHR, lipid profile, blood pressure and other microvascular complications (OR for sTNFR1: 2.592 (1.222-5.498), P = 0.013; OR for sTNFR2: 2.124 (1.258-3.587), P = 0.005).

CONCLUSIONS

The activity of the TNF-alpha system is increased in subjects with type 1 diabetes mellitus and diabetic neuropathy, regardless of their glycaemic control and cardiovascular risk factors associated with insulin resistance. These results suggest that TNF-alpha may play a pathogenic role in the development of diabetic neuropathy.

Tumour necrosis factor receptors (TNFRs) in Type 2 diabetes. Analysis of soluble plasma fractions and genetic variations of TNFR2 gene in a case-control study

AIMS

We have studied the relationships between soluble fractions of tumour necrosis factor receptors (sTNFR1 and sTNFR2) in Type 2 diabetes (DM2) and its chronic microvascular complications. Likewise, we have analysed the genetic susceptibility of 196T > G exon6/CA-repeat intron 4 mutations in the TNFR2 gene in this population.

METHODS

A case-control study was conducted to examine the role of sTNFRs in 345 DM2 patients and 173 healthy subjects. The mutations were studied in all healthy subjects and in a subset of 232 patients.

RESULTS

sTNFRs levels were similar in healthy and DM2 patients. A positive correlation between age and both sTNFRs was observed in healthy subjects. In DM2 patients, sTNFR1 showed a positive correlation with age, systolic blood pressure and leptin levels (r = 0.53, P < 0.0001; r = 0.28, P = 0.005; r = 0.46, P < 0.0001, respectively) and sTNFR2 was positively correlated with age, triglycerides and leptin levels (r = 0.34, P < 0.0001; r = 0.21, P < 0.0001; r = 0.28, P = 0.002, respectively). Patients with micro- or macroalbuminuria showed higher plasma levels of sTNFR1 and sTNFR2 than normoalbuminuric patients, after adjusting for confounding variables (B = 0.85, P = 0.022, 95% CI: 0.12-1.58 for sTNFR1 and B = 1.50, P < 0.001, 95% CI: 0.67-2.33 for sTNFR2). In DM2 patients, TT-exon 6 homozygous showed lower levels of sTNFR1 [2,4 (1.1) vs. 3.4 (1.2) ng/ml], and the CA273-allele tracked with elevated plasma HDL-cholesterol [1.8 (0.7), 1.4 (0.3) and 1.3 (0.3) mm, for CA273/273, CA273/- and CA-/-, respectively]. No association was seen with other analysed variables.

CONCLUSIONS

Our findings suggest that chronic TNF activation may have some pathogenic role in diabetic nephropathy in DM2 patients. Genetic variations in exon 6/intron 4 of the TNFR2 gene do not predispose to a major risk for DM2 or its microvascular complications.

Body fat distribution, insulin mediated suppression of non-esterified fatty acids and plasma triglycerides in obese subjects

Triglyceride levels and free fatty acid metabolism are influenced by body fat distribution. To test whether the pattern of fat distribution in obese subjects results in distinct insulin mediated suppression of non-esterified fatty acids which could account for differences in plasma triglycerides, we studied 59 obese subjects who were classified according to waist-to-hip ratio. Non-esterified fatty acids and insulin response to a 75 g oral glucose tolerance test were higher in abdominal obesity. Total non-esterified fatty acids response, after adjustment for sex, showed a positive association with waist-to hip ratio (r = 0.292; p < 0.05). The abdominal obese group had higher fasting triglycerides (1.74+/-0.83 versus 1.11+/-0.71 mmol/L; p = 0.003) and lower glucose/insulin ratio (5.2+/-2.3 versus 7.1+/-2.4; p = 0.003). Stepwise multiple regression analysis showed that triglyceride levels are explained by fasting and 120 min non-esterified fatty acids and by glucose/insulin ratio. We conclude that abdominal obesity is associated with a higher resistance to insulin mediated suppression of non-esterified fatty acids in obese subjects. Variation of triglyceride concentrations in obesity is dependent on both fasting and 120 min non-esterified fatty acids as well as on insulin sensitivity to glucose utilization.

Dehydroepiandrosterone sulphate, body fat distribution and insulin in obese men

Sex steroid hormones may be involved in determining body fat distribution in men. Recent evidence suggests that insulin may be an important regulator of sex hormones metabolism in men. Few data, however, are available on the relationship of dehydroepiandrosterone sulphate (DHEA-SO4), a major secretory product of the adrenal gland, to regional distribution of body fat or to insulin levels in men. We therefore examined the association of DHEA-SO4, total testosterone and free testosterone to waist-to-hip ratio (WHR) and to subscapular-to-triceps ratio (STR) in 34 obese, otherwise healthy men. In addition, we examined the relation between these sex steroid hormones and insulin response to an oral glucose tolerance test. DHEA-SO4 was significantly positively related to STR and significantly negatively related to insulin area. These associations remained significant after adjustment for age and obesity. Using multiple linear regression, DHEA-SO4 was independently related to both STR and insulin area. Without claiming any causality in the observed associations, we conclude that, in obese men, high DHEA-SO4 levels are related to centralized adiposity, while low DHEA-SO4 levels are related to hyperinsulinemia.

Protein intake during aggressive calorie restriction in obesity determines growth hormone response to growth hormone-releasing hormone after weight loss

OBJECTIVE

We evaluated the influence of two types of calorie restriction, total fast or very low calorie diet, on GH responsiveness to GHRH in severely obese patients.

DESIGN

Twenty patients with massive obesity underwent one of two types of calorie restriction, total fast (10 patients) or very low calorie diet (10 patients).

MEASUREMENTS

Fasting GH, IGF-I, glucose, insulin and GH secretion after GHRH (100 ug i.v.) were assessed in all patients before and after diet therapy.

RESULTS

Both types of diet produced similar weight reduction (total fast, 5.6 +/- 1.6 kg/m2 vs very low calorie diet, 5.6 +/- 1.5 kg/m2 mean +/- SD). A significant increase in the integrated GH secretion was observed after weight loss with very low calorie diet (17 +/- 9 vs 27 +/- 12 mU/l min; P < 0.05). However, no change was found in GH response after weight loss with total fast (13 +/- 5 vs 15 +/- 7 mU/l min). Glucose, insulin and IGF-I levels showed a significant decrease with weight reduction which was similar for both groups.

CONCLUSION

These findings suggest that the type of dietary manipulation during calorie restriction in obese patients may influence the changes in GH response to GHRH after weight loss.