Secretion Index Research Articles

Growth Hormone Treatment Response: Associated Factors and Stimulated Growth Hormone Secretion Indices in Prepubertal Children with Idiopathic GH Deficiency.

This study aimed to examine the correlation between the growth response in prepubertal children with idiopathic growth hormone (GH) deficiency after 1 year of treatment with GH to the initial clinical and biochemical parameters. Additionally, the secretion dynamics of GH was also studied by analyzing the GH stimulation test profiles in relation to the GH treatment response. This retrospective study included 84 prepubertal children (47 males and 37 females) with a definitive diagnosis of GH deficiency. The GH secretory indexes GHmax, GH secretion rate, and GH secretion volume were analyzed in relation to the response to recombinant human growth hormone (rhGH) treatment as defined by the index of responsiveness (IoR). Correlation and regression models were used to identify the best clinical and biochemical predictors to rhGH treatment. ResultsIoR was negatively correlated with the age (r=-0.607, p<0.01) and positively with the distance of child's height from its midparental height (MPH) r=0.466 (p<0.01) and pretreatment growth velocity (r=0.247, p<0.05). GH secretory indexes were correlated, and the highest association was observed between GHmax and GH secretion volume (r=0.883, p<0.01). Among the GH secretory indexes, GHmax was the best predictor of IoR (β coef. = -0.514, p<0.001) followed by the GH secretion volume (β coef. = -0.47, p<0.001) and GH secretion rate (β coef. = -0.367 p<0.001). The age and the distance of child's height from its MPH are major predictors of GH treatment response in children with idiopathic GH deficiency. The calculation of the other GH secretory indexes GHSR and GHSV are not better predictors of response to GH than GHmax. The combination of clinical and biochemical indexes may improve the pretreatment assessment of response to rhGH treatment.

Exploring insulin resistance and pancreatic function in individuals with overweight and obesity: Insights from OGTTs and IRTs.

To investigate insulin resistance and pancreatic β-cell function in overweight or obese people under the same glucose tolerance conditions. The subjects were categorized based on the results of the oral glucose tolerance test (OGTT) and the BMI classification criteria. Basal and postprandial glucose concentrations, insulin concentrations, pancreatic β-cell function (HOMA-β), the insulin resistance index (HOMA-IR), and the insulin early secretion index (ΔI30/ΔG30) were compared between the different weight groups. Among individuals with similar glucose tolerances, those in the obese group presented higher HOMA-β, HOMA-IR, and ΔI30/ΔG30 values than did those in the normal weight and overweight groups. Additionally, in individuals with normal glucose tolerance and early diabetes, OGTT 1-h plasma glucose concentrations demonstrated a stronger correlation with early insulin secretion across different body weights. When the same glucose-tolerant population was grouped by weight, OGTTs were significantly less different than IRTs. Therefore, integrating both tests is the optimal approach. In individuals with preobesity, there is an increase in pancreatic β-cell function to maintain normal blood glucose levels. As the disease progresses, obesity substantially increases insulin resistance, which acts as a disease-promoting factor. Furthermore, OGTT 1-h plasma glucose concentrations are strongly correlated with insulin secretion in normal or early diabetic populations.

The relationship between residual insulin secretion and subclinical cardiovascular risk indices in young adults with type 1 diabetes.

Patients with type 1 diabetes (DM1), even in the setting of adequate glycaemic control, have an excess risk for developing cardiovascular disease. Residual insulin secretion (RIS), measured by detectable C-peptide levels in patients with DM1, might protect against diabetes-related complications. This study aimed to examine the relationship between residual insulin secretion and prognostic markers of cardiovascular complications in patients with DM1. A total of 137 patients with DM1 were included in this analysis. They were of young age (<45 years), with an established diagnosis of over two years before the study entry and without a history of cardiovascular complications. All patients underwent complete clinical and laboratory evaluation. A c-peptide measurement of ≥0.05 ng/ml was used to identify the presence of RIS. Pulse wave velocity (PWV), cardiac autonomic function assessed both at rest, by total power of heart rate variability and dynamically, by the expiration to inspiration (e/i) index, albumin to creatinine ratio (ACR), and high sensitivity CRP (hs-CRP) were used as predictive biomarkers of cardiovascular complications. Female participants represented 63.5% of the population [mean age: 29.7 (±8.1) years, mean HbA1c: 7.6% (±1.4), median diabetes duration:15 (10-21) years, median age at diabetes diagnosis: 13 (8-17) years]]. The median value of fasting c-peptide was 0.04 (0.03-0.05) ng/ml, and RIS was detected in 32 patients (23.4%). Patients with RIS had a shorter diabetes duration, an older age at diagnosis and a lower BMI, while no significant association was found between residual c-peptide and age or HbA1c. RIS was significantly associated with lower PWV values [8.1 m/s² (7-8.7) vs 9.2 m/s² (7.8-10.1), p <0,001], higher total power values [1124 Hz (600-3277) vs 577 Hz (207-2091), p <0,001], and higher E/I measurements [1.4 (1.2-1.5) vs. 1.3 (1.2-1.4), p=0.01]. No significant association was noted between RIS and either ACR or hs-CRP. In multivariable linear regression analysis, the association between RIS and lower PWV values remained significant (p= 0.007) regardless of age, sex, diabetes duration or age of diagnosis, blood pressure and BMI. Similarly, residual insulin secretion retained a significant independent association with total power (p= 0.032) and E/I (p=0.045). In young patients with DM1, free of macrovascular complications, residual insulin secretion is independently associated with more favorable prognostic markers of subclinical atherosclerosis and cardiac autonomic function.

Insulin secretion, sensitivity, and clearance in normoglycemic Black and White adults with parental type 2 diabetes: association with incident dysglycemia

IntroductionEthnic disparities in the prevalence and pathophysiology of type 2 diabetes are well documented, but prospective data on insulin dynamics vis-à-vis pre-diabetes/early dysglycemia risk in diverse populations are scant.Research design...

Mesenteric Visceral Lipectomy (MVL) Improves Glucose Tolerance in Type 2 Diabetes Patients: A Pilot Study.

Increased mesenteric visceral fat is associated with the metabolic syndrome, insulin resistance, and type 2 diabetes. Using Targeted Cell Separation and Extraction Technology (TC-SET), we examined the effect of removal of intra-abdominal fat, specifically small bowel mesenteric fat, on glycemic control and insulin sensitivity in 7 obese, poorly controlled type 2 diabetic individuals (HbA1c = 8.9±0.2%; FPG = 211±12 mg/dl). At month 6, both HbA1c and FPG significantly declined to 7.7% (p=0.01) and 140 mg/dl (p<0.01). At month 12, both the FPG (172 mg/dl, P=0.02) and HbA1c (8.1%, P=0.10) tended to increase. Time-in-range (CGM) increased from 22% to 74% (month 6, p<0.001) and 50% (month 12, p<0.05). Suppression of endogenous (hepatic) glucose production increased from 29% to 45% (p<0.05) and to 43% (p<0.01) at months 6 and 12, respectively; whole body (muscle) insulin-mediated glucose disposal did not change significantly at months 6 and 12. Body weight (106.8 to 103.3 kg) and percent body fat (33.3 to 31.6%) both decreased slightly (p<0.05) at month 12. Hepatic fat content (1H-MRS) decreased significantly (23.9±3.7 to 19.1±3.4%, P<0.005) at month 12. Insulin secretion and disposition index during OGTT increased more than 2-fold at month 6 (both p<0.05), and these improvements persisted at 12 months. Mesenteric visceral lipectomy shows potential as a novel, minimally invasive approach to improve glycemic control in suboptimally controlled type 2 diabetes patients, but further controlled studies are needed to confirm these findings and better understand the potential benefits of MVL.

A critique of measurement of defective insulin secretion and insulin sensitivity as a precision approach to gestational diabetes.

Precision medicine approaches to gestational diabetes mellitus (GDM) have categorised patients according to disease pathophysiology (insulin resistance, insulin insufficiency or both), and demonstrated associations with clinical outcomes. We aimed to assess whether using enhanced processing to determine indices of insulin secretion and sensitivity is analytically robust, reproducible in a different population, and useful diagnostically and prognostically in clinical practice. A total of 1308 pregnant women with one or more risk factors for GDM who underwent a 75 g OGTT at one of nine hospital sites were recruited to this observational study. Specimens were collected for determination of glucose levels using standard and enhanced procedures, HbA1c and insulin analysis. GDM diagnosis and management followed National Institute for Health and Care Excellence guidance. We categorised women into pathophysiological subtypes: insulin-resistant GDM (HOMA2-S < 25th centile of the population with normal glucose tolerance [NGT]), insulin-insufficient GDM (HOMA2-B < 25th centile), both or neither. We assessed associations with pregnancy outcomes using logistic regression. Using enhanced specimen handling, 1027/1308 (78.5%) women had NGT, with 281/1308 (21.5%) being classified as having GDM. Of this group, 135/281 (48.0%) had insulin-resistant GDM, 73/281 (26.0%) had insulin-insufficient GDM and 2/281 (0.7%) had both insulin-resistant and insulin-insufficient GDM. Unexpectedly, 71 patients (25.3%) had GDM with both HOMA2-S and HOMA2-B ≥25th centile (GDM-neither). This novel subgroup appeared to be relatively insulin-sensitive in the fasting state but developed marked post-load hyperglycaemia and hyperinsulinaemia, suggesting an isolated postprandial defect in insulin sensitivity that was not captured by HOMA2-B or HOMA2-S. Women within most GDM subgroups had comparable pregnancy outcomes to those of normoglycaemic women, and HOMA2-B and HOMA2-S were weak predictors of pregnancy outcomes. Maternal BMI predicted a similar number of outcomes to HOMA2-S, suggesting that there was no additional predictive value in adding HOMA2-S. Similar findings were obtained when using different indices and standard specimen handling techniques. Precision categorisation of GDM using HOMA2-S and HOMA2-B does not provide useful diagnostic or prognostic information, but did distinguish a novel subgroup of patients with GDM, characterised by an isolated postprandial defect in insulin sensitivity.

The relationship of changes in insulin demand and insulin adequacy over the life course.

Insulin requirements in the human body undergo continuous changes in response to growth and development. We assessed the life course relationships between insulin demand and insulin adequacy. Three independent Chinese cohorts (204 children, aged [mean ± SD] 7.0 ± 0.5 years; 214 adolescents, aged 15.0 ± 1.8 years; 605 adults, aged 41.5 ± 9.3 years), recruited between 1998 and 2013, underwent OGTT tests. Indices of insulin sensitivity and insulin secretion were calculated based on paired glucose/insulin values during fasting, early phase and late phase of OGTT. Insulin demand and insulin adequacy were calculated by standardised major axis (SMA) regression from the paired insulin sensitivity and secretion indices. We derived the natural logarithm of ratio between the exponential functions of insulin adequacy and insulin demand (RAD) index for further evaluating the relationship between insulin demand and adequacy. The risk of abnormal glucose tolerance (AGT) was evaluated by logistic regression analyses. Area under the receiver-operating characteristic curve (AUC-ROC) analyses, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indices were used to demonstrate the discriminative value of the RAD method model. Adolescents had the lowest insulin sensitivity and the highest insulin secretion in all phases (fasting, early and late phase) of the OGTT, as compared with children and adults in each phase (all p<0.001). Adolescents had the highest insulin demand in all phases and lowest insulin adequacy in the fasting phase (p<0.001). In general, adults had the lowest insulin adequacy in both the early phase (p>0.05) and late phase (p<0.001) of the OGTT. Adolescents had negative RAD values irrespective of overweight and obesity, while, in general, children and adults had positive RAD values (p<0.001 between age groups in each of the fasting, early and late phases of the OGTT). Participants with RAD values below the 25th percentile had a higher risk of AGT compared with those above the 25th percentile (fasting-phase OR 1.86 [95% CI 1.18, 2.91]; early-phase OR 1.99 [95% CI 1.24, 3.19]; late-phase OR 2.49 [95% CI 1.57, 3.97]). The late-phase RAD index had the best performance in evaluating the risk of AGT compared with the fasting- and early-phase RAD indices (late-phase AUC-ROC = 0.635 [95% CI 0.583, 0.687]; late-phase NRI = 0.350 [95% CI 0.190, 0.510]; late-phase IDI = 0.033 [95% CI 0.015, 0.050]). The relationship between insulin demand and insulin adequacy changed throughout the life course. Adolescents had an imbalanced relationship between insulin demand and insulin adequacy, while, in general, children and adults had a balanced relationship. RAD is a novel index that was used to efficiently describe this relationship and evaluate the risk of AGT.

Role of unilateral-cannulating adrenal venous sampling for the subtyping of primary aldosteronism for adrenalectomy: Experience from a low-volume center.

Current guidelines recommend adrenal venous sampling (AVS) for subtyping primary aldosteronism (PA). However, bilateral adrenal cannulation failure is common especially at low-volume centers. The role of unilateral-cannulating AVS in selecting patients for unilateral adrenalectomy is unclear. Fifty consecutive patients underwent AVS between 2009 and 2023 and thirty-three (66%) underwent unilateral adrenalectomy. We defined unilateral PA (uPA) by the normalized plasma aldosterone and the aldosterone-renin ratio following unilateral adrenalectomy. We examined the effectiveness of unilateral-cannulating AVS in identifying uPA. 88%, 50%, and 48% of patients had the left, right, and bilateral adrenal veins successfully cannulated, respectively. Among patients with bilateral successful cannulation, a lateralization index (LI)>4 provided a sensitivity of 100% and a positive predictive value (PPV) of 86.7% for uPA. Thresholds for the contralateral suppression index (CSI) and relative aldosterone secretion index (RASI) were derived from this subgroup and applied to the entire cohort. CSI <0.5 demonstrated a sensitivity of 76.5% and PPV of 92.9% for uPA, whereas RASI >2.4 showed a sensitivity of 85.0% and PPV of 94.4% for uPA. With CSI <0.5 or RASI >2.4 combined, a higher PPV (95.5%) was achieved when compared to computed tomography and iodocholesterol scintigraphy (86.2% and 62.5%, respectively). Despite unsuccessful bilateral cannulation, our study confirms that unilateral-cannulating AVS can effectively select patients for unilateral adrenalectomy based on a combination of CSI or RASI criteria.

2-Hydroxylation is a chemical switch linking fatty acids to glucose-stimulated insulin secretion

Glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells is metabolically regulated and progressively diminished during the development of type 2 diabetes (T2D). This dynamic process is tightly coupled with fatty acid metabolism, but the underlying mechanisms remain poorly understood. Fatty acid 2-hydroxylase (FA2H) catalyzes the conversion of fatty acids to chiral specific (R)-2-hydroxy fatty acids ((R)-2-OHFAs), which influences cell metabolism. However, little is known about its potential coupling with GSIS in pancreatic β cells. Here, we showed that Fa2h knockout decreases plasma membrane localization and protein level of glucose transporter 2 (GLUT2), which is essential for GSIS, thereby controlling blood glucose homeostasis. Conversely, FA2H overexpression increases GLUT2 on the plasma membrane and enhances GSIS. Mechanistically, FA2H suppresses the internalization and trafficking of GLUT2 to the lysosomes for degradation. Overexpression of wild-type FA2H, but not its mutant with impaired hydroxylase activity in the pancreatic β-cells, improves glucose tolerance by promoting insulin secretion. Levels of 2-OHFAs and Fa2h gene expression are lower in high-fat diet-induced obese mouse islets with impaired GSIS. Moreover, lower gene expression of FA2H is observed in a set of human T2D islets when the insulin secretion index is significantly suppressed, indicating the potential involvement of FA2H in regulating mouse and human GSIS. Collectively, our results identified an FA chemical switch to maintain the proper response of GSIS in pancreatic β cells and provided a new perspective on the β-cell failure that triggers T2D.

Interactions of genes with alcohol consumption affect insulin sensitivity and beta cell function.

Alcohol consumption has complex effects on diabetes and metabolic disease, but there is widespread heterogeneity within populations and the specific reasons are unclear. Genetic factors may play a role and warrant exploration. The aim of this study was to elucidate genetic variants modulating the impact of alcohol consumption on insulin sensitivity and pancreatic beta cell function within populations presenting normal glucose tolerance (NGT). We recruited 4194 volunteers in Nanjing, 854 in Jurong and an additional 5833 in Nanjing for Discovery cohorts 1 and 2 and a Validation cohort, respectively. We performed an OGTT on all participants, establishing a stringent NGT group, and then assessed insulin sensitivity and beta cell function. Alcohol consumption was categorised as abstinent, light-to-moderate (<210 g per week) or heavy (≥210 g per week). After excluding ineligible individuals, an exploratory genome-wide association study identified potential variants interacting with alcohol consumption in 1862 NGT individuals. These findings were validated in an additional cohort of 2169 NGT individuals. Cox proportional hazard regression was further employed to evaluate the effect of the interaction between the potential variants and alcohol consumption on the risk of type 2 diabetes within the UK Biobank cohort. A significant correlation was observed between drinking levels and insulin sensitivity, accompanied by a consequent inverse relationship with insulin resistance and beta cell insulin secretion after adjusting for confounding factors in NGT individuals. However, no significant associations were noted in the disposition indexes. The interaction of variant rs56221195 with alcohol intake exhibited a pronounced effect on the liver insulin resistance index (LIRI) in the discovery set, corroborated in the validation set (combined p=1.32 × 10-11). Alcohol consumption did not significantly affect LIRI in rs56221195 wild-type (TT) carriers, but a strong negative association emerged in heterozygous (TA) and homozygous (AA) individuals. The rs56221195 variant also significantly interacts with alcohol consumption, influencing the total insulin secretion index INSR120 (the ratio of the AUC of insulin to glucose from 0 to 120 min) (p=2.06 × 10-9) but not disposition index. In the UK Biobank, we found a significant interaction between rs56221195 and alcohol consumption, which was linked to the risk of type 2 diabetes (HR 0.897, p=0.008). Our findings reveal the effects of the interaction of alcohol and rs56221195 on hepatic insulin sensitivity in NGT individuals. It is imperative to weigh potential benefits and detriments thoughtfully when considering alcohol consumption across diverse genetic backgrounds.

1-Hour Post-Load Glucose: Early Screening for High Risk of Type 2 Diabetes in Koreans with Normal Fasting Glucose.

With rising the prevalence of type 2 diabetes mellitus (T2DM) and prediabetes, the importance of 1-hour post-load plasma glucose (1-h PG) for early hyperglycemia screening is emphasized. This study investigates the utility of 1-h PG in predicting T2DM in adults with normal fasting plasma glucose (FPG) levels. 7,504 participants were categorized into three groups: normal glucose tolerance (NGT) with 1-h PG < 155 mg/dL, NGT with 1-h PG ≥ 155 mg/dL, and impaired glucose tolerance (IGT). Insulin sensitivity and secretion indices were compared between groups at baseline, and T2DM incidence was analyzed using Cox proportional hazards models. The predictive abilities of 1-h PG and 2-hour post-load plasma glucose (2-h PG) were assessed with receiver operating characteristic analysis. At baseline, the composite insulin sensitivity index in the NGT & 1-h PG ≥ 155 mg/dL group was similarly reduced as in the IGT group (P = .076). Over a mean follow-up of 7.4 years, T2DM developed in 960 patients (12.8%). The highest risk was in the IGT group (hazard ratio [HR] 5.47), followed by the NGT & 1-h PG ≥ 155 mg/dL group (HR 2.74), compared to the NGT & 1-h PG < 155 mg/dL group. The 1-h PG level had a higher area under the curve (0.772) than other glycemic parameters, including 2-h PG. Even with normal FPG, a 1-h PG ≥ 155 mg/dL indicates lower insulin sensitivity similar to IGT and increased T2DM risk, making it a more effective early screening tool than 2-h PG.

Oral glucose tolerance test curve shape in Mexican children and adolescents with and without obesity.

Mexican children with obesity are at a higher risk of developing type 2 diabetes mellitus (T2DM). The aim of the study was to compare oral glucose tolerance test (OGTT) characteristics: time of peak glucose, glucose level≥155 mg/dL at 1 h, presence of metabolic syndrome (MetS), sensitivity, secretion, and oral disposition index (oDI) in children with and without obesity, according to oral glucose tolerance curve shape: monophasic or biphasic. Cross-sectional study including 143 children. Groups were divided into (a)obese: biphasic (B-Ob) (n=55) and monophasic (M-Ob) (n=50), (b)without obesity: biphasic (B-NonOb) (n=20) and monophasic (M-NonOb) (n=18). Late glucose peak was more frequent in the M-Ob group (p<0.001). Glucose levels≥155 mg/dL and MetS were more frequent in the M-Ob group but did not show significance. The groups with obesity (biphasic and monophasic) had higher indices of insulin resistance and insulin secretion compared to the nonobese groups (biphasic and monophasic) (p<0.001). AUC glucose was higher in the M-Ob group (p<0.05), and AUC insulin was higher in the M-NonOb group. oDI (Matsuda) was significantly lower in the M-Ob group compared to the other groups (p<0.001), and oDI-HOMA IR was higher in M-NonOb group (p=0.03). All OGTT parameters could help to identify Mexican children at increased risk of developing T2DM, not only fasting plasma glucose and 2 h glucose. M-Ob in non-T2DM Mexican children reflects an early defect in glucose metabolism. Higher level of IR indexes in M-NonOb vs. B-NonOb could indicate an increased risk for T2DM of genetic origin.

Relationship of Inflammatory Mediators (Interleukin and Cortisol Concentrations) with Corneal Epithelial Quantifiable Metrics

PurposeTo investigate the relationship of inflammatory biomarkers with corneal epithelial quantifiable metrics in patients with keratoconus and in healthy eyes. DesignProspective observational comparative study. ParticipantsThis study included 100 eyes of 100 patients, 48 eyes of 48 patients with KC, and 52 healthy eyes of 52 healthy controls. MethodsThe concentrations of tear cytokines were investigated in both groups: interleukin (IL) 1B, IL6, IL8, IL10, IL12p70 and TNFα were obtained by capillary flow and measured using flow cytometer. Cortisol concentrations were determined in both groups from the most proximal hair segment as an index of cumulative secretion and measured by liquid chromatography mass spectrometry. Epithelial variables were obtained with optical coherence tomography (OCT). Pearson correlation (r) was used to measure linear dependence between two different variables. Main Outcome MeasuresInvestigating the existence, strength, and significance of any correlation between inflammatory biomarkers (IL1B, IL6, IL8, IL10, IL12p70, TNFα and hair cortisol concentration) and OCT corneal epithelial quantifiable variables such as minimum and maximum epithelial thickness of the map, difference between the minimum and maximum (Epithelial Min-Max) and standard deviation of the epithelial thickness of the map (Epithelial Std Dev) and average epithelial thickness of the superior and inferior regions of the map. ResultsEyes with keratoconus presented statistically significantly higher levels of IL1b (p=0.02), IL6 (p <0.0001), IL8 (p <0.0001), and TNFα (p <0.0001) and hair cortisol concentration (p=0.01) compared to healthy controls.There was a significant correlation between IL6 and measurement Epithelium Min-Max [Pearson= -0.59 (-0.69, -0.47); p<0.0001] and Epithelial standard deviation (Std Dev) [Pearson= +0.56 (0.44, 0.67); p<0.0001]. There was a significant correlation between hair cortisol concentration and Epithelium Min-Max [Pearson=-0.27 (-0.42, -0.1); p<0.0001] and Epithelium Std Dev groups [Pearson= +0.2 (0.03, 0.36); p=0.021]. There was also a significant correlation between TNFα and Epithelial Max. [Pearson= -0.37 (-0.55, 0.17); p<0.0001]. We found no significant correlation between the concentration of IL1b, IL8, IL10 and IL2p70 with any epithelium parameters. ConclusionsThe higher concentration of inflammatory markers (IL6 and hair cortisol) in eyes with keratoconus present a significant correlation with OCT metrics identifying epithelial variability, such as Epithelial Min-Max and Std Dev. These findings demonstrate the role of chronic inflammation in eyes with keratoconus, and that these epithelial changes detectable with OCT are sensitive to this inflammatory process.

Liver fat accumulation is associated with increased insulin secretion independent of total, visceral, and pancreatic fat.

Studies in heterogenous groups of people with respect to sex, body mass index (BMI), and glycemic status (normoglycemia, impaired glucose tolerance, diabetes), indicate no relationship between liver fat accumulation and pancreatic insulin secretion. To better understand the association of liver fat with insulin secretion. Cross-sectional analysis of 61 men with abdominal obesity who had high liver fat (HLF, ≥5.6% by magnetic resonance spectroscopy, n=28) or low liver fat (LLF, n=33), but were balanced on BMI, total body fat, visceral adipose tissue (VAT), and pancreatic fat. A frequently sampled 5-hour oral glucose tolerance test with 11 samples, in conjunction with mathematical modeling, was used to compute indices of insulin sensitivity and insulin secretion (oral minimal model). Compared to subjects with LLF, those with HLF had significantly greater fasting glucose, insulin, C-peptide, and triglyceride; lower high-density lipoprotein-cholesterol; but similar glycated hemoglobin. Areas under the 5-hour curve for glucose, insulin, and C-peptide were greater in the HLF group than the LLF group (by ∼10%, ∼38%, and ∼28%, respectively); fasting and total postprandial insulin secretion rates were ∼37% and ∼50% greater, respectively (all P<0.05); whereas the insulinogenic index was not different. HLF subjects had lower whole-body and hepatic insulin sensitivity, disposition index, and total insulin clearance than LLF subjects (all P<0.05). Accumulation of liver fat is associated with increased insulin secretion independently of total adiposity, abdominal fat distribution, and pancreatic fat. Thereby, hyperinsulinemia in fatty liver disease is partly because of insulin hypersecretion and partly because of impaired insulin clearance.

Cystic fibrosis-related diabetes develops from a combination of insulin secretion defects and insulin resistance.

The relative contributions of insulin secretory defects and possible additional contribution of insulin resistance for the development of cystic fibrosis (CF)-related diabetes (CFRD) are poorly understood. We aimed to (a) determine which indices of insulin resistance predict progression to CFRD, and (b) to model the relative contributions of insulin secretory function and insulin resistance to predict the risk of CFRD. Three hundred and three individuals living with CF underwent a 2-h oral glucose tolerance test with blood sampling every 30 min at 12-24-month intervals until they developed CFRD or until the end of follow-up (up to 15 years). Indices of insulin resistance (e.g. Stumvoll) and insulin secretion were calculated from oral glucose tolerance test glucose and insulin measurements. CFRD-free survival was assessed by survival analysis. Estimated insulin resistance showed associations with glucose homeostasis and risk of progression to CFRD. The CFRD-free survival was significantly different between quartiles of insulin resistance (p < 0.0001). When patients were subdivided according to both insulin resistance and insulin secretion (insulinogenic index), CFRD-free survival was significantly lower in those with combined lowest insulin secretion and highest insulin resistance (Stumvoll) indices (hazard ratio: 11.2; p < 0.0001). There was no significant difference when the same analysis was performed for the nine other indices. Insulin resistance is correlated with glucose homeostasis and the risk of progression to CFRD. Patients combining low insulin secretion and high insulin resistance had the greatest odds of developing CFRD over a 15-year period.

β-cell function and long-term glycemic control in patients newly diagnosed with type 2 diabetes with moderate hyperglycemia after a 6-month course of basal insulin therapy

AimsTo evaluate whether treatment with insulin is advantageous compared with oral anti-diabetic drugs (OAD) for patients newly diagnosed with type 2 diabetes with moderate hyperglycemia. MethodsPatients newly diagnosed with type 2 diabetes with moderate hyperglycemia were recruited and randomized to receive insulin, metformin or sitagliptin treatment. The oral glucose tolerance test (OGTT) was performed before treatment and 6 months thereafter. The primary outcome was the glycohemoglobin (HbA1c) level change. For the secondary efficacy analysis, the β-cell function and insulin sensitivity were calculated from the OGTT, as was the proportion of subjects who reached the treatment target (HbA1c level < 7.0 % or < 6.5 %) at 6 months. ResultsWe randomized 50 patients to the three groups and 32 patients who received the allocated treatment were analyzed. The change of HbA1c level in the insulin, metformin, and sitagliptin groups was − 2.06 ± 1.37 %, −0.43 ± 0.32 %, and − 1.62 ± 0.92 %, respectively. This change was smallest in the metformin group. There was no significant difference in the changes or final HbA1c levels between the insulin and sitagliptin groups. The treat-to-target (HbA1c level < 7.0 %) rates in the insulin, metformin and sitagliptin were 75 %, 50 % and 100 %, respectively. The treat-to-target rates were not significantly different among the three groups. The insulin secretion indices, including the Matsuda index and HOMA-IR, indicated that the groups did not differ after 6 months of therapy. ConclusionA 6-month course of basal insulin therapy did not benefit patients newly diagnosed with diabetes with moderate hyperglycemia in terms of insulin sensitivity or insulin secretion.

Insulin sensitivity, disposition index and insulin clearance in cystic fibrosis: a cross-sectional study

Aims/hypothesisThe aim of this study was to investigate insulin secretion, insulin sensitivity, disposition index and insulin clearance by glucose tolerance status in individuals with cystic fibrosis (CF) and exocrine pancreatic insufficiency.MethodsIn a cross-sectional study, we conducted an extended (ten samples) OGTT in individuals with pancreatic-insufficient CF (PI-CF). Participants were divided into normal glucose tolerance (NGT), early glucose intolerance (EGI), impaired glucose tolerance (IGT) and CF-related diabetes (CFRD) groups. We used three different oral minimal models to assess insulin secretion, insulin sensitivity and insulin clearance during the OGTT. We evaluated insulin secretion using total secretion (Φ total), first-phase secretion (Φ dynamic) and second-phase secretion (Φ static) from the model, and we estimated the disposition index by multiplying Φ total and insulin sensitivity.ResultsAmong 61 participants (NGT 21%, EGI 33%, IGT 16%, CFRD 30%), insulin secretion indices (Φ total, dynamic and static) were significantly lower in the CFRD group compared with the other groups. Insulin sensitivity declined with worsening in glucose tolerance (p value for trend <0.001) and the disposition index declined between NGT and EGI and between IGT and CFRD. Those with CFRD had elevated insulin clearance compared with NGT (p=0.019) and low insulin secretion (Φ total) was also associated with high insulin clearance (p<0.001).Conclusions/interpretationIn individuals with PI-CF, disposition index declined with incremental impairment in glucose tolerance due to a reduction in both insulin secretion and insulin sensitivity. Moreover in CF, reduced insulin secretion was associated with higher insulin clearance.Graphical

Diabetes-associated Genetic Variation in MTNR1B and Its Effect on Islet Function.

Multiple common genetic variants have been associated with type 2 diabetes, but the mechanism by which they predispose to diabetes is incompletely understood. One such example is variation in MTNR1B, which implicates melatonin and its receptor in the pathogenesis of type 2 diabetes. To characterize the effect of diabetes-associated genetic variation at rs10830963 in the MTNR1B locus on islet function in people without type 2 diabetes. The association of genetic variation at rs10830963 with glucose, insulin, C-peptide, glucagon, and indices of insulin secretion and action were tested in a cohort of 294 individuals who had previously undergone an oral glucose tolerance test (OGTT). Insulin sensitivity, β-cell responsivity to glucose, and Disposition Indices were measured using the oral minimal model. The Clinical Research and Translation Unit at Mayo Clinic, Rochester, MN. Two cohorts were utilized for this analysis: 1 cohort was recruited on the basis of prior participation in a population-based study in Olmsted County. The other cohort was recruited on the basis of TCF7L2 genotype at rs7903146 from the Mayo Biobank. Two-hour, 7-sample OGTT. Fasting, nadir, and integrated glucagon concentrations. One or 2 copies of the G-allele at rs10830963 were associated with increased postchallenge glucose and glucagon concentrations compared to subjects with the CC genotype. The effects of rs10830963 on glucose homeostasis and predisposition to type 2 diabetes are likely to be partially mediated through changes in α-cell function.

Insulin resistance and secretion change after 3 years follow-up and the risk for developing diabetes in non-diabetic adults

Purpose : To determine 3-years natural change of insulin resistance and secretion in non-diabetic Chinese adults and corresponding risk for developing diabetes. Methods : Population-based cohort study was performed in Chinese adults (35-74 years) from 2009 to 2015. Fasting plasma glucose and serum insulin was determined in 1882 subjects (701 men) at baseline and re-tested in 1087 (377 men). Insulin resistance was estimated with HOMA insulin resistance index (HOMA-IR) and insulin secretion with HOMA insulin secretion index (HOMA-IS). The change of HOMA-IR and HOMA-IS was calculated as: the value at follow-up minus that at baseline

Prospective associations between breast feeding, metabolic health, inflammation and bone density in women with prior gestational diabetes mellitus

IntroductionThe aim of the study is to investigate prospective associations between breastfeeding and metabolic outcomes, inflammation, and bone density in women with prior gestational diabetes mellitus (GDM).Research design and methodsWe...