Review of Diabetic Studies最新文献

Background: Gastrointestinal complications in diabetes may affect glucose and endocrine homeostasis. Glucose-dependent insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1), and leptin regulate glucose homeostasis, food intake, and gastric emptying.

Aim: The aim was to investigate associations between diabetes complications and glucose homeostasis and plasma levels of GIP, GLP-1, and leptin.

Methods: Sixteen diabetes patients (seven men) were examined with gastric emptying scintigraphy and 72-h continuous subcutaneous glucose monitoring, 14 with the deep-breathing test, and 12 with esophageal manometry. A fiber-rich breakfast was given during the second day of glucose registration. Blood samples were taken 10 min and right before a fat-rich breakfast, as well as 10, 20, 30, 45, 60, 90, 120, 150, and 180 min afterwards. 20 healthy volunteers acted as controls. Plasma was analyzed regarding GIP, GLP-1, and leptin by Luminex.

Results: Gastroparesis lowered maximal concentration (c-max) (p = 0.003) and total area under the curve (tAUC) (p = 0.019) of glucose levels as well as d-min (p = 0.043) of leptin levels. It tended to lower baseline (p = 0.073), c-max (p = 0.066), change from baseline (d-max) (p = 0.073), and tAUC (p = 0.093) of GLP-1 concentrations. Esophageal dysmotility tended to lower tAUC of glucose levels (p = 0.063), and c-min (p = 0.065) and tAUC (p = 0.063) of leptin levels. Diabetes patients had a higher baseline concentration of glucose (p = 0.013), GIP (p = 0.023), and leptin (p = 0.019) compared with healthy subjects.

Conclusions: Gastric and esophageal dysmotility are associated with both lesser increases in postprandial glucose elevations and decreased postprandial changes in GLP-1 and leptin.

Background: Current screening methods for gestational diabetes mellitus (GDM) are insufficient in detecting the risk of GDM in the first trimester of the pregnancy. Recent metabolomic studies have detected altered amino acid and acylcarnitine concentrations in type 2 diabetes (T2D). Because of the similarities between T2D and GDM, the determination of these metabolites may be useful in early screening for GDM.

Aim: To evaluate the association between GDM and first-trimester maternal serum concentrations of ten amino acids and 31 acylcarnitines.

Methods: This retrospective case-control study included data from pregnant women screened at Oulu University Hospital between 1.1.2008 and 31.12.2011. A total of 31,146 women participated voluntarily in a first-trimester combined screening (for chromosomal abnormalities). The study population included 69 women who developed GDM during pregnancy and 295 women without diabetes before or after pregnancy. The serum concentrations of ten amino acids and 31 acylcarnitines were analyzed from frozen serum samples taken in the first-trimester screening. Multiple of median (MoM) values were compared between the two groups.

Results: In the GDM group, serum levels of arginine were significantly higher (1.13 MoM vs. 0.97 MoM), and those of glycine (0.93 MoM vs. 1.03 MoM) and 3-hydroxy-isovalerylcarnitine (0.86 MoM vs. 1.03 MoM) significantly lower compared to the control group (all p < 0.01). In each case, arginine, glycine, and 3-hydroxy-isovaleryl-carnitine would have detected 46%, 32%, and 39% of GDM cases, with a false-positive rate of 20%. Combining these three metabolites with the first-trimester serum marker pregnancy-associated plasma protein A (PAPP-A) and prior risk (age, BMI, and smoking) achieved a detection rate of 72%.

Conclusion: There are significant differences in the serum levels of arginine, glycine, and 3-hydroxy-isovalerylcarnitine between controls and women who subsequently develop GDM. These differences were already existent in the first trimester of the pregnancy. The use of metabolites in combination with prior risk and first-trimester PAPP-A represents a reliable method to identify women at risk of GDM.

Background: Prediabetes has been related to an increased risk of developing diabetes and cardiovascular disease (CVD).

Aim: The aim of the present study was to examine the effect of the Mediterranean diet on diabetes and CVD risk in subjects with impaired fasting glucose (IFG, i.e. fasting plasma glucose 100-125 mg/dl).

Methods: During 2001-2002, 3042 men and women (>18y) were enrolled for the study. The participants showed no clinical evidence of CVD or any other chronic disease, and were living in the greater Athens (Greece) area. In 2011 and 2012, the 10-year follow-up examinations were performed, including a working sample of n = 1875 participants without diabetes at baseline. Adherence to the Mediterranean diet at baseline evaluation was assessed using the MedDietScore (range 0-55).

Results: The prediabetic subjects (n = 343) had a significantly higher incidence of diabetes (25% vs. 10%, p < 0.001) and CVD (17.8% vs. 12.3%, p = 0.007) compared with subjects with normal glucose values. A significant trend towards lower diabetes and CVD incidence was observed with medium and high adherence to the Mediterranean diet compared with low adherence (p < 0.001). High adherence to the Mediterranean diet (>35/55 score) was associated with lower 10-year incidence of diabetes and CVD. In multiple logistic regression models, participants with high levels of adherence to the Mediterranean diet were significantly less affected by diabetes and CVD than those with low adherence levels.

Conclusion: High adherence to the Mediterranean diet is associated with a low risk of developing diabetes and CVD in prediabetic subjects.

Background: Pancreatic islet-cell dysfunction is a hallmark in the development of diabetes, but the reasons for the primary β-cell defect are still elusive. Elevated circulating proline levels have been found in subjects with insulin resistance, obesity, and type 2 diabetes. Therefore, we assessed β-cell function, gene expressions, and cell death after long-term exposure of pancreatic β-cells to excess proline in vitro.

Methods: Isolated mouse islets and INS-1E cells were incubated with and without excess proline. After 72 h, we examined: (1) β-cell function, including basal insulin secretion (BIS) and glucose-stimulated insulin secretion (GSIS), (2) transcription factors related to insulin gene expression and enzymes involved in the tricarboxylic acid cycle and cholesterol biogenesis, (3) cellular triglycerides (TG) and cholesterol content, (4) the death of INS-1E cells and 3H thymidine incorporation, and (5) protein expression of INS-1E cells in response to proline by proteomics.

Results: We found that high doses of proline increased BIS and decreased GSIS in both isolated mouse islets and INS-1E cells. MafA, insulin 1, and the cytochrome c oxidase subunit VIa polypeptide 2 mRNA expressions were all downregulated, indicating that proline impaired insulin gene transcription and mitochondrial oxidative phosphorylation. In contrast, mevalonate decarboxylase gene expression was upregulated, and simultaneously, cholesterol content in INS-1E cells was enhanced. Protein profiling of INS-1E cells revealed that cytosolic non-specific dipeptidase and α enolase were differentially expressed.

Conclusions: Our results indicate that proline-induced insulin transcription and mitochondrial oxidative phosphorylation impairment may contribute to the β-cell dysfunction observed in type 2 diabetes. Caution should be applied in interpreting the pathophysiological role of proline since very high proline concentrations were used in the experiments.

Aim: To identify dietary patterns among apparently healthy individuals and to determine their long-term effect on diabetes incidence.

Methods: During 2001-2002, a random sample of 3,042 men and women (18-89 years old), living in greater Athens, was randomly selected to participate in the study. During 2011-2012, the 10-year follow-up was performed in 2,583 participants (15% drop-out rate). After excluding participants with diabetes at baseline and those for whom no information on diabetes status was available at follow-up, the working sample consisted of 1,485 participants. Dietary habits were assessed by means of a validated semi-quantitative, food frequency questionnaire. Factor analysis was performed to extract dietary patterns from 18 food groups.

Results: Diabetes diagnosis at follow-up was made in 191 participants, yielding an incidence rate of 12.9%. Six factors (i.e. dietary patterns) were identified that explained 54% of the variation in consumption. After adjusting for major confounders, and stratification by age-group, logistic regression revealed that the most healthful pattern consisted of the consumption of fruits, vegetables, legumes, bread, rusk, and pasta which reduced the 10-year diabetes risk by 40%, among participants aged 45-55 years. The association reached marginal statistical significance (95% CI: 0.34, 1.07), while no significant association was observed for the other age-groups. When the analysis was additionally adjusted for carbohydrate percentage, statistical significance was lost completely, suggesting a possibly mediating effect of this macronutrient.

Conclusions: The results confirm the potentially protective effect of a plant-based dietary pattern in the primary prevention of diabetes, in particular among middle-aged people. Carbohydrate content may be a specific factor in this relationship; other micronutrients found in plant-based food groups may also play a role.

Medical nutrition therapy constitutes an important lifestyle intervention in diabetes management. Several nutrition patterns have been effective in improving diabetes control, but there has been a debate about the optimal macronutrient composition in diabetes meal planning. For many years, the recommended diets for persons with and without diabetes were similar, i.e. heart-healthy and low in fat. For almost three decades, carbohydrates have been lauded, lipids demonized, and proteins considered of little importance. However, in the past few years, this concept has been questioned and reassessed. Modern nutritional recommendations for people with diabetes are headed towards individualization, but lack specific guidelines. Nutritional algorithms may help nutritionists in diabetes meal planning. This review aims to discuss: 1) the effects of the three major macronutrients (carbohydrates, proteins, and lipids) on glucose levels, 2) current recommendations for macronutrient intake for people with diabetes, and 3) specific parameters that need to be taken into consideration when determining the macronutrient composition for a person with diabetes, for example body mass index, degree of insulin resistance, HbA1c value, and lipid profile (especially triglycerides and HDL cholesterol). These aspects are analyzed in the context of the results of recent studies, especially randomized controlled trials (RCTs). Finally, we introduce an individualized nutritional concept that proposes carbohydrate over lipid restriction, substitution of SFAs with MUFAs and PUFAs, and adequate intake of dietary fiber, which are key factors in optimizing diabetes management.