Changes Over Time in Hepatic Markers Predict Changes in Insulin Sensitivity, β-Cell Function, and Glycemia

Associations of alanine aminotransferase/aspartate aminotransferase with insulin resistance and β-cell function in women

We tested whether alanine aminotransferase/aspartate aminotransferase (ALT/AST), a marker of hepatosteatosis, associates with insulin resistance, β-cell function and postglucose glycemia. We studied 311 young and 148 middle-aged Japanese women, whose BMI averaged < 23.0 kg/m². Insulinogenic index and Matsuda index were evaluated in 110 young and 65 middle-aged women. In two groups of women, ALT/AST was associated positively with homeostasis model assessment insulin resistance (HOMA-IR) and inversely with Matsuda index. In middle-aged women only, the ratio was also associated positively with fasting and postload glycemia and HbA1c. The ratio showed negative association with disposition index (a product of insulinogenic index and Matsuda index). On multivariate linear regression analysis, HOMA-IR emerged as a single determinant of ALT/AST in young and middle-aged women (standardized β: 0.209, p = 0.003 and 0.372, p = 0.002, respectively). ALT/AST was associated with insulin resistance and β-cell function even in non-obese Japanese women, suggesting a pathophysiologic basis in its prediction of diabetic risk.

Association between ALT/AST and Muscle Mass in Patients with Type 2 Diabetes Mellitus

Objective

The alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio is thought to be related to metabolic disorders and insulin resistance. Type 2 diabetes mellitus (T2DM) is a high-risk population for low muscle mass. This study was performed to evaluate the association between ALT/AST and muscle mass in subjects with T2DM.

Method

This cross-sectional study enrolled 1068 subjects (566 males and 502 females) with T2DM. General information, medical history, and blood samples were collected. Skeletal muscle index (SMI) was detected using dual-energy X-ray absorptiometry. Logistic regression analysis was utilized to determine the correlation of ALT/AST and low muscle mass in subjects with T2DM. Multiple linear regression analysis was utilized to evaluate the association between ALT/AST, SMI and other metabolic characteristics.

Result

Of all subjects, 115 men (20.3%) and 71 women (14.1%) presented low muscle mass. ALT/AST was related to an increased risk for low muscle mass in both genders. Multiple linear regression analysis displayed that SMI was negatively associated with ALT/AST, age, glycosylated hemoglobin (HbA1c), and high-density lipoprotein cholesterol (HDL) in male group. While in female group, SMI was positively associated with systolic blood pressure (SBP) and negatively associated with ALT/AST and age. Furthermore, ALT/AST was associated with age and BMI in both genders.

Conclusion

ALT/AST was negatively associated with muscle mass in subjects with T2DM.

Association of distinct γ-glutamyltransferase trajectories with incident hyperglycemia using latent class growth mixture modeling: A longitudinal cohort study of Chinese adults

AIMS

To elucidate the association between distinct latent γ-glutamyltransferase (GGT) increasing trajectories in life time and incident hyperglycemia.

METHODS

4547 subjects were followed up for 3 years (January 2016-December 2019), and data regarding fasting plasma glucose, HbA_1c, GGT, and other indices were recorded. Latent class growth mixed modeling (LCGMM) was used to analyze GGT latent trajectories.

RESULTS

A three-class quadratic model was selected as the best fit by LCGMM. Subjects were categorized into three latent classes: high-increasing (n = 98, 2.16%), low-increasing (n = 364, 8.01%), and stable (n = 4085, 89.83%) classes. Adjusted hazard ratios of hyperglycemia for the high-increasing and low-increasing classes were 1.341 (1.076-2.051) and 1.264 (1.048-1.525) when compared with stable class, respectively. Odds Ratios (ORs) of GGT slopes were confirmed in the 28-57-year age group, shaped like an "M", ranging from 1.144 (1.059, 1.237) to 2.502 (1.384-3.862). Significant differences in the associations between model-estimated GGT values and hyperglycemia incidence were observed from 28 to 51 years of age, with ORs ranging from 1.011 (1.011, 1.012) to 1.014 (1.012, 1.019).

CONCLUSIONS

Our study demonstrated that subjects in GGT increasing classes exhibited higher risks of developing hyperglycemia. A steeper GGT slope is a more effective predictor of hyperglycemia than the GGT value.

Protective effects of N(1)-2,4-dihydroxybenzylidene-N(4)-2-hydroxybenzylidene-S-methyl-thiosemicarbazidato-oxovanadium (IV) on oxidative brain injury in streptozotocin-induced diabetic rats

Diabetes is usually accompanied by increased production of free radicals or impaired antioxidant defenses. The brain is a target tissue of the oxidative attacks caused by diabetes, and there are observed changes in the biochemical parameters of this tissue in the hyperglycemic state. In this study, we aimed to show the effect of N(1)-2,4-dihydroxybenzylidene-N(4)-2-hydroxybenzylidene-S-methyl-thiosemicarbazidato-oxovanadium (IV) (VOL) compound on diabetic damaged brain tissue, induced by streptozotocin (STZ) on 3.0-3.5-month-old male rats. Single dose of STZ at 65 mg/kg was used to make rats diabetic. Four groups were created randomly. Group (i): control (intact) animals; Group (ii): VOL given control animals; Group (iii): STZ-induced diabetic animals; and Group (iv): orally VOL administered STZ-induced diabetic rats. VOL (0.2 mM/kg/day) administration to control and diabetic animals was performed for a period of 12 days. At the end of day 12, the brain tissues were taken and homogenized. The clear supernatants were used for the determination of glutathione (GSH), lipid peroxidation (LPO), nonenzymatic glycosylation (NEG), and protein levels. Alanine and aspartate transaminases and acetylcholinesterase (AChE), myeloperoxidase (MPO), xanthine oxidase (XO), and oxidative stress marker enzymes activities were also estimated from the homogenates. According to the obtained results, there is found significant elevation of MDA and NEG levels and activities of transaminases, MPO and XO; whereas the GSH content and the activities of AChE and antioxidant enzymes were strongly decreased in the STZ-induced diabetic brain tissues in comparison to control group animals. Twelve days of administration of VOL complex to the diabetic animals reversed all biochemical parameters significantly in diabetic brain tissues. Our findings suggest that the VOL complex may be an ideal candidate to be used as an anti diabetic agent to improve oxidative injury and protect the brain tissue against damage caused by diabetes. This healing effect of the VOL complex may be due to its antioxidant activity and the insulin-mimetic effects of vanadium.

ALT/AST as an Independent Risk Factor of Gestational Diabetes Mellitus Compared with TG/HDL-C

Objective

This study aimed to find the association between alanine transaminase-to-aspartate aminotransferase ratio (ALT/AST) and the incidence of gestational diabetes mellitus (GDM).

Methods

A total of 1128 pregnant women were included in this prospective, double-center, observational cohort study. ALT, AST and total bilirubin (TBil) were tested during 6–12 weeks of gestation and 75-g oral glucose tolerance test (OGTT) was conducted during 24–28 weeks of gestation to screen GDM. The association between ALT/AST and glucose concentration during OGTT was analyzed by linear regression model. The OR with 95% CI for incidence of GDM associated with ALT/AST was estimated by binary logistic regression. The discriminatory values of ALT/AST and triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) for GDM were calculated by the area under the receiver operating characteristic curve (ROC-AUC).

Results

The incidence of GDM was 22.07% (249/1128). ALT/AST was higher in GDM group than in NGT group (0.92 [0.75, 1.18] vs 0.80[0.65, 1.02], P <0.001). ALT/AST had positive correlations with fasting blood glucose, 1-hour and 2-hour blood glucose concentration during OGTT (0.089 [95% CI: 0.034, 0.163], 0.176 [95% CI: 0.052, 0.104], and 0.115 [95% CI: 0.199, 0.609], respectively). The OR of ALT/AST for incidence of GDM was 1.603 (95% CI:1.097, 2.344). The ROC-AUC of ALT/AST and TG/HDL-C reached 0.615 (95% CI: 0.575, 0.655) and 0.619 (95% CI: 0.580, 0.659), respectively.

Conclusion

ALT/AST in early pregnancy was an independent risk factor of GDM. The predictive ability of ALT/AST was similar to TG/HDL-C for GDM.

Underestimated Prediabetic Biomarkers: Are We Blind to Their Strategy?

Type 2 Diabetes (T2D) is currently one of the fastest growing health challenging, a non-communicable disease result of the XXI century lifestyle. Given its growing incidence and prevalence, it became increasingly imperative to develop new technologies and implement new biomarkers for early diagnosis in order to promote lifestyle changes and thus cause a setback of the disease. Promising biomarkers have been identified as predictive of T2D development; however, none of them have yet been implemented in clinical practice routine. Moreover, many prediabetic biomarkers can also represent potential therapeutical targets in disease management. Previous studies have identified the most popular biomarkers, which are being thoroughly investigated. However, there are some biomarkers with promising preliminary results with limited associated studies; hence there is still much to be understood about its mechanisms and associations in T2D pathophysiology. This work identifies and discusses the promising results of Galectin-3, Ophthalmate and Fetuin-A.

Postpartum circulating microRNA enhances prediction of future type 2 diabetes in women with previous gestational diabetes

AIMS/HYPOTHESIS

Type 2 diabetes mellitus is a major cause of morbidity and death worldwide. Women with gestational diabetes mellitus (GDM) have greater than a sevenfold higher risk of developing type 2 diabetes in later life. Accurate methods for postpartum type 2 diabetes risk stratification are lacking. Circulating microRNAs (miRNAs) are well recognised as biomarkers/mediators of metabolic disease. We aimed to determine whether postpartum circulating miRNAs can predict the development of type 2 diabetes in women with previous GDM.

METHODS

In an observational study, plasma samples were collected at 12 weeks postpartum from 103 women following GDM pregnancy. Utilising a discovery approach, we measured 754 miRNAs in plasma from type 2 diabetes non-progressors (n = 11) and type 2 diabetes progressors (n = 10) using TaqMan-based real-time PCR on an OpenArray platform. Machine learning algorithms involving penalised logistic regression followed by bootstrapping were implemented.

RESULTS

Fifteen miRNAs were selected based on their importance in discriminating type 2 diabetes progressors from non-progressors in our discovery cohort. The levels of miRNA miR-369-3p remained significantly different (p < 0.05) between progressors and non-progressors in the validation sample set (n = 82; 71 non-progressors, 11 progressors) after adjusting for age and correcting for multiple comparisons. In a clinical model of prediction of type 2 diabetes that included six traditional risk factors (age, BMI, pregnancy fasting glucose, postpartum fasting glucose, cholesterol and triacylglycerols), the addition of the circulating miR-369-3p measured at 12 weeks postpartum improved the prediction of future type 2 diabetes from traditional AUC 0.83 (95% CI 0.68, 0.97) to an AUC 0.92 (95% CI 0.84, 1.00).

CONCLUSIONS

This is the first demonstration of miRNA-based type 2 diabetes prediction in women with previous GDM. Improved prediction will facilitate early lifestyle/drug intervention for type 2 diabetes prevention.

Hepatokine levels during the first or early second trimester of pregnancy and the subsequent risk of gestational diabetes mellitus: a systematic review and meta-analysis

PURPOSE

The relationship between hepatokine levels during the first or early second trimester of pregnancy and the subsequent risk of gestational diabetes mellitus (GDM) have been studied extensively. However, conclusions remain debateable whether hepatokines are potential markers of GDM. We conducted a meta-analysis of published articles to understand the association between circulating levels of selected hepatokines (including FGF21, fetuin-A, afamin, adropin, ficolin-3, selenoprotein P, ANGPTL4 and AGF) and the risk of GDM.

MATERIALS AND METHODS

We searched the PubMed, Embase, Cochrane Library and Web of Science databases for studies published before January 2021 that examined the association between hepatokines and GDM (Prospero Registration# CRD42020191408). The quality was assessed by the Newcastle-Ottawa Scale (NOS). Pooled standard mean differences (SMDs) and weighted mean differences (WMDs) with 95% confidence intervals (CIs) were used to compare the levels of hepatokines in different groups using fixed effects or random effects models. Meta-regression analysis and publication bias were conducted in accordance with standard methods. The trim-fill adjustment method was used to further assess the possible effect of publication bias. Sensitivity analysis was performed by omitting each study one at a time.

RESULTS

The meta-analysis included 31 observational studies relating hepatokine levels to GDM in 4729 participants (1908 GDM, 2821 non-GDM). Serum FGF21 levels in patients with GDM were higher than those in healthy pregnant women during the second trimester and after delivery (SMD 0.89, [95% CI] 0.01-1.78 for the second trimester; SMD 1.42, [95% CI] 0.86-1.98 for after delivery). The serum levels of afamin in patients with GDM were significantly higher than those in healthy pregnant women during the first trimester and before pregnancy (SMD 0.51, [95% CI] 0.15-0.86 for first trimester; SMD 0.97, [95% CI] 0.45-1.50 for before pregnancy). Serum adropin levels in patients with GDM were higher than those in healthy pregnant women during the first and third trimesters of pregnancy (SMD 4.26, [95% CI] 3.30-5.23 for the first trimester; SMD 4.02, [95% CI] 3.09-4.94 for the third trimester). The serum levels of ficolin-3 in GDM patients were higher than those in healthy pregnant women during the second and third trimesters of pregnancy (WMD 1.43, [95% CI] 0.91-1.96 for the second trimester; SMD 1.28, [95% CI] 0.72-1.84 for the third trimester). The serum AGF level of patients with GDM was higher than that of healthy pregnant women in the control group in the third trimester (WMD 61 [95% CI] 37.04-81.96). The serum levels of selenoprotein P in patients with GDM were higher than those in healthy pregnant women in the control group during the first trimester (WMD 7.09 [95% CI] 4.6-9.57).

CONCLUSIONS

Measurement of circulating hepatokines in the first or second trimester of pregnancy may improve the identification of women at risk of developing GDM later. Prospective evaluation of the combination of hepatokines and maternal characteristics for early identification of those who do and do not require OGTT is warranted. Additional well-designed prospective studies with longitudinal assessment of hepatokines during pregnancy are needed to understand the trajectories and dynamic associations of hepatokines with GDM risk.

Association Between Aspartate Aminotransferase to Alanine Aminotransferase Ratio and Incidence of Type 2 Diabetes Mellitus in the Japanese Population: A Secondary Analysis of a Retrospective Cohort Study

BACKGROUND

The study on the association between aspartate aminotransferase to alanine aminotransferase (AST/ALT) ratio and the risk of type 2 diabetes mellitus (T2DM) was limited. Therefore, we conducted a secondary analysis based on online data to explore whether there was an association between the AST/ALT ratio and incident T2DM among a large number of Japanese people.

METHODS

The study was a retrospective cohort study. We downloaded the NAGALA (NAfld in Gifu area) data from DATADRYAD website between 2004 and 2015. This present study included 15,291 participants. Cox proportional-hazards regression, generalized additive models and subgroup analyses were used to find out the association between the AST/ALT ratio and T2DM events.

RESULTS

The negative relationship was shown between AST/ALT ratio and incident T2DM (HR = 0.617, 95% CI: 0.405-0.938) in our study. A non-linear relationship and saturation effect were found between them, and the inflection point was 0.882. It indicated that the AST/ALT ratio was negatively correlated with incident T2DM when the AST/ALT ratio was less than the inflection point (HR = 0.287, 95% CI: 0.126-0.655, p = 0.0030). We found that exercise modified their relationship (P for interaction = 0.0024), and people who did not exercise associated strongly (HR = 0.464 95% CI: 0.290-0.741).

CONCLUSION

AST/ALT ratio was negatively associated with T2DM risk, and their relationship was non-linear and had a saturation effect. When the AST/ALT ratio was less than 0.882, they showed a significant negative correlation.

Association of Time With Reliability of Maternal Recall of Infant Birth Weight

This cohort study evaluates the association of birth weights measured at delivery and those recalled by mothers after 3 months and 3 years.

A randomized trial of dapagliflozin and metformin, alone and combined, in overweight women after gestational diabetes mellitus

BACKGROUND

Women with a history of gestational diabetes mellitus are at a substantially increased risk of gestational diabetes mellitus recurrence and type 2 diabetes. Weight gain, particularly increased central adiposity after delivery, is strongly associated with deterioration of pancreatic beta cell compensation for insulin resistance. Weight management after gestational diabetes mellitus could have a significant benefit in these women who are at a high risk of developing type 2 diabetes.

OBJECTIVE

This study aimed to evaluate the treatment efficacy of dapagliflozin and metformin, alone and in combination, on body weight and anthropometric, cardiovascular, and metabolic parameters in overweight women with a recent history of gestational diabetes mellitus.

STUDY DESIGN

This was a prospective, single-blind, randomized, outpatient clinical trial with 3 parallel treatment groups. Overweight or obese (body mass index>25) females (n=66; ≥18-45 years) with gestational diabetes mellitus in pregnancy in the past 12 months were randomized in a single-blind manner to dapagliflozin, metformin, or dapagliflozin-metformin for 24 weeks. Body weight, height, body mass index, waist circumference, waist-to-height ratio, and blood pressure were determined at baseline and trial completion. Oral glucose tolerance tests were performed at baseline and 24 weeks to assess glycemia and mean blood glucose and calculate insulin sensitivity and secretion measures. Plasma lipid fractions, thyroid-stimulating hormone, and liver enzymes were also assessed in the fasting sample at the beginning and completion of the study trial.

RESULTS

The study was completed by 49 participants (74%). Significant reduction of weight, waist circumference, and waist-to-height ratio and improved glycemia and insulin sensitivity index derived from oral glucose tolerance test were found with dapagliflozin-metformin vs metformin monotherapy. Both dapagliflozin and dapagliflozin-metformin therapy were superior to metformin in increasing high-density lipoprotein levels, reducing triglyceride concentrations, lowering the triglyceride-to-high-density lipoprotein cholesterol ratio, and improving glucose excursion after an oral glucose tolerance test. The early insulin response to a glucose challenge significantly improved with only dapagliflozin-metformin compared with single-drug treatments.

CONCLUSION

This is the first report comparing the efficacy of a sodium-glucose cotransporter 2 inhibitor alone and in combination with metformin in this patient population. We found that combination dapagliflozin-metformin treatment over a 24-week period had a greater positive effect on body weight, waist circumference, and glycemic, cardiovascular, and metabolic parameters than metformin monotherapy in overweight or obese at-risk women with a recent history of gestational diabetes mellitus.

Changes Over Time in Uric Acid in Relation to Changes in Insulin Sensitivity, Beta-Cell Function, and Glycemia

CONTEXT

Serum uric acid has been linked to risk of type 2 diabetes (T2DM), but debate persists as to whether it plays a causal role. Indeed, it is unclear if changes in uric acid relate to the pathophysiologic determinants of T2DM (insulin resistance, beta-cell dysfunction), as would be expected if causal.

OBJECTIVE

To evaluate the impact of changes in uric acid over 2 years on changes in insulin sensitivity, beta-cell function, and glycemia in women with and without recent gestational diabetes (GDM), a model of the early natural history of T2DM.

DESIGN/SETTING/PARTICIPANTS

At both 1 and 3 years postpartum, 299 women (96 with recent GDM) underwent uric acid measurement and oral glucose tolerance tests that enabled assessment of insulin sensitivity/resistance (Matsuda index, homeostasis model assessment of insulin resistance [HOMA-IR]), beta-cell function (insulin secretion-sensitivity index-2 [ISSI-2], insulinogenic index/HOMA-IR [IGI/HOMA-IR]), and glucose tolerance.

RESULTS

Women with recent GDM had higher serum uric acid than their peers at both 1 year (281 ± 69 vs 262 ± 58 µmol/L, P = 0.01) and 3 years postpartum (271 ± 59 vs 256 ± 55 µmol/L, P = 0.03), coupled with lower insulin sensitivity, poorer beta-cell function, and greater glycemia (all P < 0.05). However, on fully adjusted analyses, neither uric acid at 1 year nor its change from 1 to 3 years was independently associated with any of the following metabolic outcomes at 3 years postpartum: Matsuda index, HOMA-IR, ISSI-2, IGI/HOMA-IR, fasting glucose, 2-hour glucose, or glucose intolerance.

CONCLUSION

Serum uric acid does not track with changes over time in insulin sensitivity, beta-cell function, or glycemia in women with recent GDM, providing evidence against causality in its association with diabetes.

Effects of dynamic change in fetuin-A levels from the first to the second trimester on insulin resistance and gestational diabetes mellitus: a nested case-control study

OBJECTIVE

To examine the effects of dynamic change in fetuin-A levels before the diagnosis of gestational diabetes mellitus (GDM) on insulin resistance and GDM.

RESEARCH DESIGN AND METHODS

A total of 135 women with GDM and 135 normal glucose tolerance (NGT) women with matched age (±2 years old) and gestational age at taking the oral glucose tolerance test (OGTT) were included in this nested case-control study. Fasting venous blood samples were collected at the prenatal visit of the first trimester and during OGTT of the second trimester. Plasma concentration of fetuin-A and insulin was determined.

RESULTS

The plasma fetuin-A concentration in women with GDM was significantly higher than NGT controls in both the first trimester (medians: 403.0 pg/mL vs 273.4 pg/mL; p<0.05) and the second trimester (medians: 475.7 pg/mL vs 290.8 pg/mL; p<0.05) and notably increased from the first to the second trimester. Multivariate linear regression analysis showed that the change in fetuin-A concentration was associated with the changes in fasting insulin, homeostasis model assessment (HOMA) of insulin resistance, and HOMA of β-cell function (HOMA-β) (p<0.05). The highest quartile of the increase in fetuin-A concentration from the first to the second trimester was associated with a higher risk of developing GDM compared with the lowest quartile (OR 2.14; 95% CI 1.05 to 4.37).

CONCLUSIONS

The dynamic change in fetuin-A levels was associated with the changes in insulin resistance and β-cell function from the first to the second trimester, and was associated with an increased risk of the development of GDM, indicating that fetuin-A could be a biomarker to predict the risk of GDM.

TRIAL REGISTRATION NUMBER

NCT03814395.

TyG-er: An ensemble Regression Forest approach for identification of clinical factors related to insulin resistance condition using Electronic Health Records

BACKGROUND

Insulin resistance is an early-stage deterioration of Type 2 diabetes. Identification and quantification of insulin resistance requires specific blood tests; however, the triglyceride-glucose (TyG) index can provide a surrogate assessment from routine Electronic Health Record (EHR) data. Since insulin resistance is a multi-factorial condition, to improve its characterisation, this study aims to discover non-trivial clinical factors in EHR data to determine where the insulin-resistance condition is encoded.

METHODS

We proposed a high-interpretable Machine Learning approach (i.e., ensemble Regression Forest combined with data imputation strategies), named TyG-er. We applied three different experimental procedures to test TyG-er reliability on the Italian Federation of General Practitioners dataset, named FIMMG_obs dataset, which is publicly available and reflects the clinical use-case (i.e., not all laboratory exams are prescribed on a regular basis over time).

RESULTS

Results detected non-conventional clinical factors (i.e., uricemia, leukocytes, gamma-glutamyltransferase and protein profile) and provided novel insight into the best combination of clinical factors for detecting early glucose tolerance deterioration. The robustness of these extracted clinical factors was confirmed by the high agreement (from 0.664 to 0.911 of Lin's correlation coefficient (r_c)) of the TyG-er approach among different experimental procedures. Moreover, the results of the three experimental procedures outlined the predictive power of the TyG-er approach (up to a mean absolute error of 5.68% and r_c=0.666,p<.05).

CONCLUSIONS

The TyG-er approach is able to carry information about the identification of the TyG index, strictly correlated with the insulin-resistance condition, while extracting the most relevant non-glycemic features from routine data.

Serum Ferritin and Glucose Homeostasis in Women With Recent Gestational Diabetes

OBJECTIVES

Serum markers of iron storage have been linked to type 2 diabetes; however, the mechanism underlying this association is unclear. In pregnancy, increased serum ferritin has been reported in women with gestational diabetes (GDM), a patient population at high risk of future type 2 diabetes. However, in the years after pregnancy, it is not known if ferritin relates to their diabetes risk or the pathophysiologic determinants thereof (insulin sensitivity and beta-cell function). Therefore, we sought to characterize the relationship between ferritin and glucose homeostasis in the early postpartum years in women with and without recent GDM.

METHODS

At both 1 and 3 years postpartum, 340 women (105 with recent GDM) underwent serum ferritin measurement and an oral glucose tolerance test that enabled assessment of insulin sensitivity and/or resistance (Matsuda index and Homeostasis Model Assessment [HOMA-IR]), beta-cell function (Insulin Secretion-Sensitivity Index-2 and insulinogenic index/HOMA-IR) and glucose tolerance.

RESULTS

Serum ferritin did not differ between women who had GDM and their peers at either 1 or 3 years postpartum. Baseline-adjusted change in ferritin between 1 and 3 years correlated with the concomitant change in C-reactive protein (r=0.21, p=0.0002) but was not associated with measures of insulin sensitivity and/or resistance, beta-cell function or glycemia. On adjusted analyses, neither baseline ferritin nor its change from 1 to 3 years was independently associated with any of the following metabolic outcomes at 3-years postpartum: Matsuda index, HOMA-IR, Insulin Secretion-Sensitivity Index-2, insulinogenic index/HOMA-IR, fasting glucose, 2-h glucose or glucose intolerance.

CONCLUSIONS

Serum ferritin is not associated with glucose homeostasis in the early years after a GDM pregnancy.

Stability of insulin and C-peptide measurement with long-term frozen storage of serum: Implications for diabetes research studies

The current era of large-scale clinical trials in diabetes has generated thousands of biological samples from study participants that are being stored long-term under frozen conditions for the future measurement of analytes of interest. Insulin and C-peptide are two such analytes that can provide insight into underlying pathophysiological processes (insulin sensitivity and β-cell function). However, the validity of the inferences that may be drawn from such future measurements is contingent on the stability of these analytes after long-term frozen storage. We conducted the present study to determine the stability of insulin and C-peptide concentrations that were first measured on fresh serum at the time of collection, followed by frozen storage at -80°C for >5 years and then repeat measurement. Bland-Altman analyses revealed good agreement between the repeated insulin measurements and between the repeated C-peptide measurements. The concordance correlation coefficient (CCC) confirmed reproducibility for both insulin (CCC 0.98, 95% confidence interval [CI] 0.96-0.99) and C-peptide (CCC 0.91, 95% CI 0.84-0.95); thus, insulin and C-peptide measurements are both stable and reproducible after long-term frozen storage of serum samples.

Metabolic Changes in Androgen-Deprived Nondiabetic Men With Prostate Cancer Are Not Mediated by Cytokines or aP2

Context

Androgen deprivation therapy (ADT) remains the cornerstone of management of prostate cancer (PCa). Previous studies have shown that men undergoing ADT develop insulin resistance and diabetes, but the mechanisms behind ADT-induced metabolic abnormalities remain unclear.

Objective

To evaluate the role of inflammatory cytokines and adipocyte protein-2 (aP2) in ADT-induced metabolic dysfunction.

Participants and Interventions

This 6-month prospective cohort study enrolled nondiabetic men with PCa about to undergo ADT (ADT group) and a control group of nondiabetic men who had previously undergone prostatectomy for localized PCa and were in remission (non-ADT group); all participants had normal testosterone at study entry. Fasting blood samples were collected at baseline and at 6, 12, and 24 weeks after initiation of ADT and at the same intervals in the non-ADT group. Glucose, insulin, lipids, inflammatory cytokines, and C-reactive protein were measured. We also measured serum aP2, an adipocyte-secreted protein that promotes hepatic glucose production. Homeostatic model assessment of insulin resistance (HOMA-IR) was calculated.

Results

Seventy-three participants formed the analytical sample (33 ADT, 40 non-ADT). HOMA-IR increased in the ADT group (estimated change = 0.25; P = 0.05), but was unchanged in the non-ADT group (0.11; P = 0.342). Serum concentrations of inflammatory cytokines or aP2 did not change significantly. There was a treatment-associated increase in total (16 mg/dL; P < 0.001), high-density lipoprotein (8 mg/dL; P < 0.001), and low-density lipoprotein (7 mg/dL; P = 0.02) cholesterol.

Conclusion

ADT-induced metabolic abnormalities were not associated with changes in circulating inflammatory cytokines or aP2 levels.