Cross-reactive peptide epitopes of Enterovirus Coxsackie B4 and human glutamic acid decarboxylase detecting antibodies in latent autoimmune diabetes in adults versus type 1 diabetes

BACKGROUND

Diagnosis of latent autoimmune diabetes in adults (LADA) is usually based on the adult age, anti-pancreatic islet cell antibodies detection, and insulin independence. This study investigates the diagnostic value of antibodies against human glutamic acid decarboxylase (hGAD) peptides in LADA and type 1 diabetes mellitus (T1DM) patients, and their cross-reactivity with an Enterovirus Coxsackie B4 (CVB4) shared epitope.

METHODS

Sera from 27 LADA patients, 23 T1DM patients, and 24 controls were tested in ELISA for antibodies against hGAD peptides and a selected sequence of P2C protein of CVB4 (CVB4P2C). Diagnostic power of peptides was analyzed by ROC-curve analysis and cross-reactivity among peptides evaluated.

RESULTS

IgM and IgG antibodies showed significant differences between LADA and T1DM versus controls for all peptides. Antibody responses present high agreement among peptides for IgM and IgG-isotypes in T1DM, which is not reproduced in LADA. IgM antibodies showed high predicting diagnostic power particularly in LADA (sensitivity > 85%, specificity 95.8%).

CONCLUSIONS

Our study highlights the usefulness of peptides as diagnostic antigens in T1DM and LADA, and extends previous findings by comparing IgM and IgG-isotype antibodies in the same population. Additionally, results highlight the role of the entourage in the shared sequon PEVKXK in GAD and CVB4P2C particularly in IgMs identification.

Adherence to a follow-up program after gestational diabetes

AIM

The aim of this study was to examine attendance for early postpartum follow-up among women with gestational diabetes mellitus (GDM), and to identify factors that influenced their likelihood of attending.

METHODS

One thousand eight hundred and nineteen women with GDM were retrospectively analyzed. During pregnancy, the following data were collected: age, family history of diabetes, ethnicity, prepregnancy BMI, fasting plasma glucose, glycated hemoglobin, gestational week of GDM diagnosis, timing and mode of delivery, newborn's birth weight and length. Glycemia and insulinemia during OGTT, lipid profile and postpartum BMI were assessed at follow-up. Based on the OGTT, women were classified as having normal glucose tolerance (NGT) or abnormal glucose tolerance (AGT), which included impaired fasting glucose (IFG), impaired glucose tolerance (IGT), IFG + IGT, and DM2. Factors predicting postpartum attendance for follow-up and onset of AGT were considered.

RESULTS

Of the 889 (48.9%) who attended the scheduled postpartum OGTT, 741 (83.4%) had NGT, while 148 (16.6%) had AGT (IFG 6.7%, IGT 7.7%, IFG + IGT 0.8%, DM2 1.5%). The predictors of adherence to follow-up were: not belonging to an immigrant group; family history of DM2; and insulin therapy in pregnancy. The same factors were also predictive of AGT. Our data suggest a role of ethnicity in both attendance for postpartum follow-up and its outcome.

CONCLUSION

Despite efforts to provide care for women with GDM, postpartum screening rates are still low among Italian women, and especially among immigrants. Hence, the need to improve these patients' awareness of the severe risk of developing diabetes after pregnancy, concentrating efforts especially on women belonging to the most at risk ethnic groups.

Celiac Disease and Pregnancy Outcomes in Patients with Gestational Diabetes Mellitus

AIM

Gestational diabetes mellitus (GDM) and celiac disease, if not diagnosed and properly treated, are associated with adverse outcomes of pregnancy. The aim of our study was to examine pregnancies complicated by GDM in celiac and nonceliac women in terms of their metabolic parameters and maternal and fetal outcomes.

METHODS

The study involved 60 women with GDM, 20 with and 40 without celiac disease. Maternal clinical and metabolic parameters (glucose and insulin levels in the oral glucose tolerance test (OGTT), fasting plasma glucose, HbA1c, lipid profile, prepregnancy BMI, gestational weight gain, and chronic diseases), pregnancy outcomes (gestational hypertension, pre-eclampsia, eclampsia, time, and mode of delivery), and fetal parameters (weight and length at birth, and neonatal complications) were recorded.

RESULTS

The two groups did not differ significantly in maternal parameters other than blood glucose levels at 120' in the diagnostic OGTT (141.2 ± 35.2 vs 161.2 ± 35.4, mg/dl, p=0.047), prepartum cLDL (127.2 ± 43.5 vs 179.6 ± 31.7 mg/dl, p ≤ 0.001), and total cholesterol (229.0 ± 45.9 vs 292.5 ± 42.1 mg/dl, p ≤ 0.001), which were significantly lower in celiac women than in nonceliac controls. Children born from celiac women had a significantly higher birth weight (3458.1 ± 409.8 vs 3209.0 ± 432.7 g, p=0.044) and ponderal index (2.89 ± 0.32 vs 2.66 ± 0.25 g/cm3, p=0.006) and were more likely to be large for gestational age (27.8% vs 2.5%, p=0.012). Analyzing the composition of the celiac and nonceliac women's diet showed that, for the same amount of kilocalories, the gluten-free diet was associated with a slight increase in the amount of carbohydrates (49.75% vs 48.54%) and a reduction in the amount of protein (21.10% vs 23.31%) and especially of fiber (9.84% vs 12.71%).

CONCLUSIONS

Celiac women with GDM have much the same pregnancy outcomes as nonceliac women with GDM, except for fetal overgrowth. Gluten-free food, being richer in carbohydrates and less rich in fiber and protein, could have a role in fetal growth in celiac women.

Genetics and Epigenetics: New Insight on Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is the most common metabolic complication of pregnancy, with a prevalence that has increased significantly in the last decade, coming to affect 12-18% of all pregnancies. GDM is believed to be the result of a combination of genetic, epigenetic and environmental factors. Following the identification of susceptibility genes for type 2 diabetes by means of genome-wide association studies, an association has also been demonstrated between some type 2 diabetes susceptibility genes and GDM, suggesting a partial similarity of the genetic architecture behind the two forms of diabetes. More recent genome-wide association studies, focusing on maternal metabolism during pregnancy, have demonstrated an overlap in the genes associated with metabolic traits in gravid and non-gravid populations, as well as in genes apparently unique to pregnancy. Epigenetic changes-such as DNA methylation, histone modifications and microRNA gene silencing-have also been identified in GDM patients. Metabolomics has been used to profile the metabolic state of women during pregnancy, based on the measurement of numerous low-molecular-weight metabolites. Measuring amino acids and conventional metabolites has revealed changes in pregnant women with a higher insulin resistance and high blood glucose levels that resemble the changes seen in non-gravid, insulin-resistant populations. This would suggest similarities in the metabolic profiles typical of insulin resistance and hyperglycemia whether individuals are pregnant or not. Future studies combining data obtained using multiple technologies will enable an integrated systems biology approach to maternal metabolism during a pregnancy complicated by GDM. This review highlights the recent knowledge on the impact of genetics and epigenetics in the pathophysiology of GDM and the maternal and fetal complications associated with this pathology condition.