Standard Oral Glucose Load Research Articles

Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults

Sucralose is an artificial non-nutritive sweetener used in foods aimed to reduce sugar and energy intake. While thought to be inert, the impact of sucralose on metabolic control has shown to be the opposite. The gut microbiome has emerged as a factor shaping metabolic responses after sweetener consumption. We examined the short-term effect of sucralose consumption on glucose homeostasis and gut microbiome of healthy male volunteers. We performed a randomised, double-blind study in thirty-four subjects divided into two groups, one that was administered sucralose capsules (780 mg/d for 7 d; n 17) and a control group receiving placebo (n 17). Before and after the intervention, glycaemic and insulinaemic responses were assessed with a standard oral glucose load (75 g). Insulin resistance was determined using homeostasis model assessment of insulin resistance and Matsuda indexes. The gut microbiome was evaluated before and after the intervention by 16S rRNA sequencing. During the study, body weight remained constant in both groups. Glycaemic control and insulin resistance were not affected during the 7-d period. At the phylum level, gut microbiome was not modified in any group. We classified subjects according to their change in insulinaemia after the intervention, to compare the microbiome of responders and non-responders. Independent of consuming sucralose or placebo, individuals with a higher insulinaemic response after the intervention had lower Bacteroidetes and higher Firmicutes abundances. In conclusion, consumption of high doses of sucralose for 7 d does not alter glycaemic control, insulin resistance, or gut microbiome in healthy individuals. However, it highlights the need to address individual responses to sucralose.

Performance of the FreeStyle Libre Flash glucose monitoring system in patients with type 1 and 2 diabetes mellitus

ObjectiveTo evaluate the performance of the FreeStyle Libre Flash continuous glucose monitoring (FSL-CGM) system against established central laboratory methods.Research design and methods20 subjects (8 type 1 diabetes mellitus, 12 type...

Is it time to implement a standardized oral glucose and fat load test to detect high risk patients? Probably not yet…

Is it time to implement a standardized oral glucose and fat load test to detect high risk patients? Probably not yet…

BMI and waist circumference are associated with impaired glucose metabolism and type 2 diabetes in normal weight Chinese adults

AimsTo examine the associations of BMI and waist circumference with glucose metabolism and (pre)diabetes among adults with BMI<25kg/m2. MethodsWe conducted a cross-sectional study in a nationally representative sample (10,098 men and 17,454 women) of Chinese adults aged ≥20years with BMI<25kg/m2. Glucose levels after at least 10hours of overnight fasting, at 30minutes and at 120minutes after a standard 75-g oral glucose load were measured. Associations of BMI and waist circumference with outcomes were examined by general linear models for continuous outcomes and by logistic regression models for dichotomous outcomes. ResultsAmong those with BMI<25kg/m2, 18.8% of men and 17.1% of women had abnormal glucose metabolism, including 4.9% of men and 3.8% of women with undiagnosed type 2 diabetes. For each SD increase in BMI (2.1kg/m2) and waist circumference (8.3cm), fasting glucose levels increased by 0.128 and 0.170mmol/L in men, and by 0.112 and 0.167mmol/L in women, respectively; the corresponding increases for 2-hour post-load glucose levels were 0.121 and 0.217mmol/L in men, and 0.241 and 0.362mmol/L in women. When simultaneously included in the same model, these associations with waist circumference were stronger than with BMI. ConclusionObesity measures are associated with abnormal glucose metabolism and diabetes, with central obesity playing a more prominent role than general obesity in Chinese population with BMI<25kg/m2. Chinese diabetes prevention and treatment programs should incorporate targeting of normal weight adults with central obesity.

13C]Glucose Breath Testing Provides a Noninvasive Measure of Insulin Resistance: Calibration Analyses Against Clamp Studies

Exhaled (13)CO2 following ingestion of [(13)C]glucose with a standard oral glucose tolerance load correlates with blood glucose values but is determined by tissue glucose uptake. Therefore exhaled (13)CO2 may also be a surrogate measure of the whole-body glucose disposal rate (GDR) measured by the gold standard hyperinsulinemic euglycemic clamp. Subjects from across the glycemia range were studied on 2 consecutive days under fasting conditions. On Day 1, a 75-g oral glucose load spiked with [(13)C]glucose was administered. On Day 2, a hyperinsulinemic euglycemic clamp was performed. Correlations between breath parameters and clamp-derived GDR were evaluated, and calibration analyses were performed to evaluate the precision of breath parameter predictions of clamp measures. Correlations of breath parameters with GDR and GDR per kilogram of fat-free mass (GDRffm) ranged from 0.54 to 0.61 and 0.54 to 0.66, respectively (all P<0.001). In calibration analyses the root mean square error for breath parameters predicting GDR and GDRffm ranged from 2.32 to 2.46 and from 3.23 to 3.51, respectively. Cross-validation prediction error (CVPE) estimates were 2.35-2.51 (GDR) and 3.29-3.57 (GDRffm). Prediction precision of breath enrichment at 180 min predicting GDR (CVPE=2.35) was superior to that for inverse insulin (2.68) and the Matsuda Index (2.51) but inferior to that for the log of homeostasis model assessment (2.21) and Quantitative Insulin Sensitivity Check Index (2.29) (all P<10(-5)). Similar patterns were seen for predictions of GDRffm. (13)CO2 appearance in exhaled breath following a standard oral glucose load with added [(13)C]glucose provides a valid surrogate index of clamp-derived measures of whole-body insulin resistance, with good accuracy and precision. This noninvasive breath test-based approach can provide a useful measure of whole-body insulin resistance in physiologic and epidemiologic studies.

Short‐term effects of a standardized glucose load on region‐specific aortic pulse wave velocity assessed by MRI

To assess the short-term effects of a standardized oral glucose load on regional aortic pulse wave velocity (PWV) using two-directional in-plane velocity encoded MRI. A randomized, controlled intervention was performed in 16 male subjects (mean ± standard deviation: age: 59±7 years, body mass index: 28±3 kg/m2) with impaired fasting glucose. The intervention consisted of an oral glucose load (75 grams of carbohydrates in 300 mL water) at 1 study day and water (300 mL) at the other study day. PWV was measured using multislice two-directional in-plane velocity-encoded MRI. PWV in the proximal aorta at 1 h post-glucose load decreased compared with PWV 1-h post-water (delta PWV: -1.0±2.6 m/s versus 0.6±2.0 m/s, P=0.02). Eight responding subjects showed a significant decrease in PWV of the proximal aorta after the glucose load and had a decreased waist circumference (P=0.037) compared with nonresponders, being one of the major criteria of the metabolic syndrome. There was no significant change in PWV of the distal aorta at 1 h post-load comparing both intervention groups. A standardized oral glucose load induces a decrease of the proximal, but not of the distal, aortic PWV. Regional response of aortic PWV may be associated with features of the metabolic syndrome.

Metformin and biomarkers relevant to neoplasia in nondiabetic patients.

e14615 Background: Use of the anti-diabetic drug Metformin has been associated with reduced risk or improved prognosis of several cancers in both lab models and retrospective population studies of diabetics. Plausible mechanisms of action include (1) reduction in serum levels of insulin or inflammatory cytokines and (2) direct effects on target cells due to action of the drug as an inhibitor of mitochondrial respiration, including activation of AMPK. Methods: Non-diabetic subjects (n = 47) consented to bloodwork and sigmoid biopsy at screening colonoscopy, metformin administration (500 mg TID) for 10 weeks, and end-of-study sigmoid biopsy and bloodwork. Serum assays were performed on both fasting and post standard oral glucose load specimens. Metformin levels were measured by mass spectroscopy. Anti-phospho-histone-3 immunostaining was used to quantify proliferation. Results: Metformin reduced fasting levels of c-peptide, insulin, and IL-6 levels by &lt; 10%, a magnitude of change that laboratory studies suggest is unlikely to be biologically significant. However, postprandial insulin levels following metformin were reduced by 18 % relative to baseline postprandial levels, a finding of potential physiologic relevance. Serum metformin level showed considerable variation between subjects (1005 ± 769 ng/ml) and this variation was not correlated with effects of metformin on epithelial proliferation. Proliferation index fell from 5.9 to 3.3, (p&lt;0.03), a change greater than predicted by in vitro studies of direct action of metformin at the concentrations measured in serum. Conclusions: Metformin lowers insulin levels even in non-diabetic subjects, and post prandial insulin levels are more sensitive indicators of metformin action than fasting biomarkers. As high insulin level has been linked to increased cancer risk and/or worse prognosis (eg J Natl Cancer Inst. 2004;96:546), this systemic action suggests clinical applications. However, direct exposure of colonic epithelial cells to high luminal concentrations of metformin may also be relevant and is one of several factors that may explain the greater inhibitory effect of the drug on colonic epithelium proliferation than that previously reported for breast or prostate.

Periodic Extraction of Interstitial Fluid from the Site of Subcutaneous Insulin Infusion for the Measurement of Glucose: A Novel Single-Port Technique for the Treatment of Type 1 Diabetes Patients

Treatment of type 1 diabetes patients could be simplified if the site of subcutaneous insulin infusion could also be used for the measurement of glucose. This study aimed to assess the agreement between blood glucose concentrations and glucose levels in the interstitial fluid (ISF) that is extracted from the insulin infusion site during periodic short-term interruptions of continuous subcutaneous insulin infusion (CSII). A perforated cannula (24 gauge) was inserted into subcutaneous adipose tissue of C-peptide-negative type 1 diabetes subjects (n=13) and used alternately to infuse rapid-acting insulin (100 U/mL) and to extract ISF glucose during a fasting period and after ingestion of a standard oral glucose load (75 g). Although periodically interrupted for extracting glucose (every hour for approximately 10 min), insulin infusion with the cannula was adequate to achieve euglycemia during fasting and to restore euglycemia after glucose ingestion. Furthermore, the ISF-derived estimates of plasma glucose levels agreed well with plasma glucose concentrations. Correlation coefficient and median absolute relative difference values were found to be 0.95 and 8.0%, respectively. Error grid analysis showed 99.0% of all ISF glucose values within clinically acceptable Zones A and B (83.5% Zone A, 15.5% Zone B). Results show that ISF glucose concentrations measured at the insulin infusion site during periodic short-term interruptions of CSII closely reflect blood glucose levels, thus suggesting that glucose monitoring and insulin delivery may be performed alternately at the same tissue site. A single-port device of this type could be used to simplify and improve glucose management in diabetes.

P241 Accuchek (TM) measurement of blood glucose correlates with true lab glucose measurement in children screened for cystic fibrosis related diabetes

BackgroundScreening for cystic fibrosis related diabetes (CFRD) is recommended as part of the cystic fibrosis annual review. For children over 10 an oral glucose tolerance test (OGTT) is recommended, but...

Intra-Individual Variability of CO2 Breath Isotope Enrichment Compared to Blood Glucose in the Oral Glucose Tolerance Test

Glucose tolerance can be assessed noninvasively using (13)C-labeled glucose added to a standard oral glucose load, by measuring isotope-enriched CO(2) in exhaled air. In addition to the clear advantage of the noninvasive measurements, this approach may be of value in overcoming the high variability in blood glucose determination. We compared within-individual variability of breath CO(2) isotope enrichment with that for blood glucose in a 75-g oral glucose tolerance test (OGTT) by adding 150 mg of d-[(13)C]glucose ((13)C 99%) to a standard 75-g glucose load. Measurements of whole blood glucose (by glucose oxidase) and breath isotope enrichment (by isotope ratio mass spectrometry) were made every 30 min for 3 h. Subjects underwent three repeat tests over a 3-week period. Values for variability of breath isotope enrichment at 3 h (∂‰180) and of area under the curve for enrichment to 180 min (AUC180) were compared with variability of the 2-h OGTT blood glucose. Breath test-derived measures exhibited lower within-subject variability than the 2-h OGTT glucose. The coefficient of variation for ∂‰180 was 7.4 ± 3.9% (mean ± SD), for AUC180 was 9.4 ± 6.3%, and for 2-h OGTT blood glucose was 13 ± 7.1% (P = 0.005 comparing ∂‰180 versus 2-h blood glucose; P = 0.061 comparing AUC180 versus 2-h blood glucose; P = 0.03 comparing ∂‰180 versus AUC180). Breath test-derived measurements of glucose handling had lower within-subject variability versus the standard 2-h blood glucose reading used in clinical practice. These findings support further development of this noninvasive method for evaluating glucose tolerance.

Effects of chronic elevation of atrial natriuretic peptide and free fatty acid levels in the induction of type 2 diabetes mellitus and insulin resistance in patients with mitral valve disease

The relationship between atrial natriuretic peptide (ANP), increased free fatty acid (FFA) and insulin resistance in patients with mitral valve disease (MVD), a group characterised by elevated atrial pressure and increased ANP levels, is not defined. The present study was performed to evaluate, in MVD patients, the relationship between increased ANP and FFA levels and insulin resistance and the role of mitral valve replacement/repair in ameliorating these metabolic alterations. Conversely, coronary heart disease (CHD) patients were evaluated before and after coronary artery bypass grafting (CABG), since they are known to be insulin resistant in the presence of chronic FFA increase. Fifty MVD patients and 55 CHD patients were studied before and 2 months after surgery and compared with 166 normal subjects. Before surgery, 56% of MVD patients had impaired glucose tolerance or newly diagnosed type 2 diabetes after a standard oral glucose load and this percentage decreased to 46% after surgery. In CHD, impaired glucose tolerance (IGT) or newly diagnosed type 2 diabetic patients were 67% of patients before and after CABG. In MVD, left atrial (LA) volume, ANP, FFA incremental area and insulin levels were higher and Insulin Sensitivity (IS) index significantly reduced while after surgery, LA volume, ANP and FFA significantly decreased and IS index significantly improved. In CHD, insulin resistance and hyperinsulinaemia were present both before and after surgery with increased tumour necrosis factor (TNF)-α and interleukin (IL)-6 levels. In MVD, a higher degree of abnormal glucose tolerance and insulin resistance are associated to increased levels of ANP and FFA, while these metabolic alterations are improved by mitral valve replacement/repair surgery. Clinical Trial.gov registration number NCT 00520962.

A Step Backward—or Is it Forward?

The time may have come—or at least will soon arrive—when the diagnostic categories related to diabetes and its close relatives, impaired glucose tolerance (IGT) and impaired fasting glucose (IFG), should be reconsidered. IGT, IFG, and the combination of the two are now considered pre-diabetes because, compared with normal glucose tolerance, they signal an increased risk of developing diabetes (1). Before 1979, when the National Diabetes Data Group defined IGT (2) and declared it to be an official diagnostic category, one either did or did not have diabetes and nondiagnostic glucose levels were de facto “normal.” A middle ground was recognized by some physicians, but it was not enshrined in all epidemiological studies or in clinical practice. The addition of IFG in 1997 for the purpose of creating a state equivalent to IGT both added to the middle ground and raised awareness and appreciation of intermediate levels of glucose intolerance (3). There was now a distinctive group of individuals whose fasting plasma glucose (FPG) lay between normal (<110 mg/dl) and the new 1997 lower diabetes cut point of 126 mg/dl and who may not meet the IGT criterion of 140–199 mg/dl 2 h after a standard oral glucose load of 75 g (3). A further refinement of IFG in 2003 altered the lower IFG cut point from 110 to 100 mg/dl, a change recommended to make both intermediate states equivalent and to define a more realistic upper limit of normal (4). Recently, however, more and more studies have demonstrated that at glycemic levels above normal but within the range of either IFG or IGT, there is an increasing risk of crossing the diabetes line (FPG 126 mg/dl and/or a 2-h post–glucose load level of 200 mg/dl) within a few years (1). These latter numbers are based on the association of …

Oral glucose tolerance test reduces arterial baroreflex sensitivity in older adults

Although postprandial decreases in blood pressure are a common cause of syncope in the older adult population, the postprandial effects of the oral glucose tolerance test on blood pressure and the arterial baroreflex remain poorly characterized in older adults. Therefore, arterial blood pressure and the arterial baroreflex were studied in 19 healthy older adults (mean age 71.7 +/- 1.1 years) who were given a standardized oral glucose load (75 g) or an isovolumetric sham drink during 2 separate sessions. All measures were taken for 120 min after treatment. Baroreflex function was assessed by using the spontaneous baroreflex method (baroreflex sensitivity, BRS). Subjects demonstrated a decrease in BRS after oral glucose that was not seen in the placebo session (two-way analysis of variance, p = 0.04). There was no significant change in systolic, mean, or diastolic blood pressure; together with a drop in BRS, this resulted in a significant tachycardia post glucose (two-way analysis of variance, p < 0.001). We conclude that healthy older adults can successfully maintain blood pressure during an oral glucose tolerance test despite a decrease in arterial BRS. Decreased BRS resulted in a tachycardic response to glucose.

Retinal Arteriolar Hemodynamic Response to a Combined Isocapnic Hyperoxia and Glucose Provocation in Early Sight-Threatening Diabetic Retinopathy

To quantify the magnitude of change of retinal arteriolar hemodynamics induced by a combined isocapnic hyperoxia and glucose provocation in diabetic patients with early sight-threatening diabetic retinopathy (DR) and in age-matched control subjects and to compare the response to that of an isocapnic hyperoxia provocation alone. The study hypothesis was that hyperglycemia reduces the retinal vascular reactivity response to a hyperoxic stimulus. The sample comprised 17 control subjects (group 1), 15 patients with no clinically visible DR (group 2), 16 patients with mild-to-moderate nonproliferative DR (group 3), and 15 patients with diabetic macular edema (group 4). Retinal hemodynamic measurements were acquired in the subjects, at baseline and 1 hour after consuming a standardized oral glucose load drink while breathing oxygen isocapnic with baseline. Retinal blood velocity and flow significantly decreased in all groups (P < or = 0.001 and P < or = 0.0002, respectively) in response to a combined isocapnic hyperoxia and glucose provocation. The maximum-to-minimum velocity ratio significantly increased (P < or = 0.005), and wall shear rate (WSR) significantly decreased (P < or = 0.0002), in groups 1, 2, and 3, but not in group 4. The vascular reactivity response was not significantly different across the groups. The control group demonstrated a reduced change in flow (P = 0.009) and WSR (P = 0.010) to the combined isocapnic hyperoxia and glucose provocation compared with that of hyperoxia alone. The vascular reactivity response to a combined isocapnic hyperoxia and glucose provocation produced a pronounced reduction in blood flow. Unlike the response to hyperoxia alone, the vascular reactivity response was not significantly different across the groups. Hyperglycemia reduced the retinal vascular reactivity response to hyperoxia in age-matched control subjects.

Food-dependent Cushing's syndrome: from molecular characterization to therapeutical results

Cortisol secretion in ACTH-independent macronodular adrenal hyperplasia (AIMAH) may be regulated by the aberrant expression of several G-protein-coupled receptors. Bilateral adrenalectomy is the treatment of choice in most cases. We searched for aberrant receptor expression in a patient with AIMAH and evaluated the response to medical and surgical treatment. A 35-year-old woman with amenorrhea, hirsutism, and hypertension presented ACTH-independent cortisol secretion with high androgen levels. Abdominal computed tomography showed bilateral adrenal macronodules (4.5 cm right and 1.0 cm left). Scintigraphy with I(131)-norcholesterol showed bilateral uptake, prevalent on the right side. Several in vivo stimulation tests were assessed before and after treatment and in vitro studies were performed after unilateral adrenalectomy. Plasma cortisol increased after a standard meal test (60%) and oral glucose loading (147%), and the response was blunted by pretreatment with 100 microg s.c. octreotide. The therapy with long-acting release octreotide (octreotide-LAR) showed an improvement in urinary free cortisol (UFC) levels. Unilateral adrenalectomy was performed and histopathology revealed macronodular AIMAH. Cortisol and androgens increased after perifusion of tumoral tissue with glucose-dependent insulinotropic polypeptide (GIP), and GIP and LH-receptor overexpression was found in both the adrenal nodules and the adjacent cortex. After surgery, UFC and androgen levels normalized followed by clinical improvement. GIP and LH-receptor expression may coexist in AIMAH, influencing the functional and morphological phenotype. Aberrant hormone receptor expression enables specific pharmacological treatment, but long-term studies are needed to evaluate its real efficacy. Unilateral adrenalectomy may be a safe initial option, particularly for asymmetric bilateral adrenal enlargements.

The oral glucose tolerance test induces myocardial ischemia in healthy older adults

Postprandial myocardial ischemia has been observed in frail older adults with postprandial hypotension and in patients with severe coronary artery disease, especially after high doses of carbohydrates. The impact of oral glucose on myocardial oxygen supply and demand in healthy older adults without postprandial hypotension or postprandial angina remains unexamined. We hypothesized that oral glucose would result in decreased myocardial oxygen supply relative to demand in a healthy older subject pool free of postprandial hypotension, reversible coronary risk factors and postprandial angina. 19 older adults (mean age 71.9+/-1.1 yr) were screened for reversible coronary risk factors. Subjects were given a standardized oral glucose load (75 g) or a sham isovolumetric unsweetened drink during two separate sessions. Indirect measures of oxygen supply (Diastolic Pressure Time Index, DPTI) and demand (Rate Pressure Product, RPP; Systolic Pressure Time Index, SPTI) were obtained from aortic arterial blood pressure waveforms. The Subendocardial Viability Ratio (SEVR, DPTI/SPTI) and DPTI/RPP were also calculated. Oral glucose resulted in decreases in both SEVR (P=0.016) and DPTI/RPP (P=0.028) in the glucose session, indicating a decrease in the relative myocardial oxygen supply to demand. This was due solely to a decrease in myocardial oxygen supply while measures of myocardial oxygen demand did not change significantly. Oral glucose decreases myocardial oxygen supply in older adults free of severe coronary artery disease and without postprandial hypotension. This represents a previously unrecognized complication of oral glucose tolerance tests in healthy older adults.

Retinal arteriolar hemodynamic response to an acute hyperglycemic provocation in early and sight-threatening diabetic retinopathy

The aim was to quantify the magnitude of retinal arteriolar vascular reactivity to a hyperglycemic provocation in diabetic patients stratified by severity of retinopathy and in age-matched controls. The sample comprised 20 non-diabetic controls (Group 1), 19 patients with no clinically visible DR (Group 2), 18 patients with mild-to-moderate non-proliferative DR (Group 3) and 18 patients with diabetic macular edema (Group 4). Retinal hemodynamic measurements using the Canon Laser Blood Flowmeter (CLBF-100) were acquired before and 1 h after drinking a standardized oral glucose load drink. The magnitude of the retinal vascular response, as well as max:min velocity ratio and wall shear rate (WSR), was calculated and compared across groups. A significant change in blood glucose level was observed for all groups ( p < 0.05). The change in blood glucose elevation was significantly less in Group 1 compared to the other groups. No significant change in arteriolar diameter, blood velocity, blood flow, max:min velocity ratio and WSR was found in patients with diabetes and in age-matched subjects without diabetes. The results of this study indicate that retinal arteriolar blood flow is unaffected by acute elevation of blood glucose using an oral glucose load drink in patients with diabetes and in age-matched controls. This lack of a blood flow response to acute hyperglycemia in patients with early sight-threatening DR may be explained by a loss of retinal vascular reactivity.

EFFECT OF POST-GLUCOSE CHALLENGE ON LIPID PROFILE IN PATIENTS WITH TYPE 2 DIABETES.

Purpose Fasting samples are required for serum lipid measurement due to the concern of elevated triglycerides (TGs) from high-fat meals. Postprandial hypertriglyceridemia could also affect the low-density lipoprotein (LDL) cholesterol values routinely calculated based on the Freidewald equation. The effect of postprandial hyperglycemia mainly from carbohydrate on lipid profile is less clear, especially among diabetic patients. The purpose of this study was to determine the changes in serum lipid panel before and after a standard oral glucose loading in patients with type 2 diabetes. Methods A convenient sample of 50 diabetic patients with fasting blood glucose Results Twenty-four percent of the patients were smokers and 96% were males, with a mean age of 67 years, BMI 28.5 kg/m2, systolic BP 130 mm Hg, and HbA1c 7.4%. Sixty-eight percent of the patients were on statin, 68% on ACE-I/ARB, and 10% on insulin. The mean values of total cholesterol (TC), LDL cholesterol, high-density lipoprotein (HDL) cholesterol, and TGs before and after glucose challenge were 166, 92, 44, 154, and 162, 92, 40, 150 (mg/dL), respectively. The decrease in TC and HDL from baseline was statistically significant (p Conclusion In this elderly and predominantly male patient population from a VA primary care clinic, we found a significantly decreased TC and HDL levels associated with hyperglycemia from oral glucose challenge. Lipid management is one of the main treatment strategies for cardiovascular risk reduction in diabetic patients. Therefore, it is clinically important to have accurate measurement of all components of lipid profile. Although the exact mechanisms for the reduction in TC and HDL associated with postprandial hyperglycemia are unknown, a strict fasting blood sample without pretest carbohydrate intake is preferred for lipid panel analysis.

PARADOXICAL RESPONSE OF URINE ALBUMIN EXCRETION ASSOCIATED WITH ORAL GLUCOSE CHALLENGE IN TYPE 2 DIABETES.

Purpose Microalbuminuria is strongly predictive of diabetic nephropathy and associated with increased cardiovascular morbidity and mortality. Little information is available regarding the relationship between postprandial hyperglycemia and microalbuminuria. We sought to determine the changes in urinary albumin excretion (Ualb) before and after a standard oral glucose loading. Methods Fifty diabetic patients in a VA primary care clinic were recruited. Excluded were those with symptomatic heart diseases, chronic inflammatory conditions, blood pressure (BP) > 140/90 mm Hg, fasting blood glucose > 250 mg/dL, and glycated hemoglobin (HbA1c) > 9%. Ualb values were determined in fasting state, at 2 and 6 hours after 75 g of glucose jelly. Other measured parameters included BP, body mass index (BMI), glucose, HbA1c, lipid panel, renal and hepatic functions, and highly sensitive C reactive protein (hs-CRP). ANOVA and linear multiple regression model were used for statistical analysis. Results There were 12 (24%) smokers and 48 (96%) males, with a mean age of 67 years, BMI 28.5 kg/m2, systolic BP 130 mm Hg, HbA1c 7.4%, and creatinine 1.04 mg/dL. Sixty eight percent of the patients were on statin, 68% on ACE-I/ARB, and 10% on insulin. Ualb at baseline and 2 and 6 hours post-glucose challenge were 71, 58, and 73 mg/L, respectively. Compared with the fasting level, 2 hours postglucose Ualb was significantly decreased (p = .028 in quadratic trends) and returned to baseline in 6 hours. There were no significant associations between the changes in Ualb and other measured parameters and use of tobacco, statin, or ACE-I/ARB. Conclusion Contrary to the common postulation that short-term hyperglycemia can cause transient elevations in Ualb, our result from this study population shows a decreased Ualb 2 hours after a glucose load. We propose the term paradoxical phenomenon. This may reflect glomerular self-protection and homeostasis in response to acute hyperglycemia. Possible mechanisms may involve glomerular osmotic or vascular changes through neuroendocrine regulation. The involvement of rennin-angiotensin system or inflammation cannot be excluded based on this study with a limited sample size and selected patient population. However, our preliminary results merit further investigation of potential mechanisms for this paradoxical phenomenon.

Effects of Binge Eating Behavior on Fuel Oxidation and Body Composition

Objective: To investigate energy expenditure and glucose metabolism after a standard oral glucose load (75 g) in 8 normal weight bulimic women and 8 normal weight control women and to evaluate the relative endocrine implication.Design: Serum glucose and insulin were measured both in basal conditions and after the glucose load; a basal endocrine assessment and body composition was evaluated and glucose induced thermogenesis (GIT) was calculated during 300 min following the glucose load.Results: Serum glucose levels were significantly lower in bulimics both in fasting and in post-prandial state. Insulin levels were similar in bulimic and control women before and after the glucose load. FSH, leptin and free urinary cortisol (FUC) were all within the normal ranges, but significantly lower in bulimic patients compared with controls (p < 0.001). Fat mass (FM) and Fat-free mass (FFM) were reduced in bulimic patients, even if they normalized after correction per body weight. Resting energy expenditure (REE) was similar in the two groups even after FFM normalization, while GIT was lower in bulimic patients and it was strongly related to free urinary chortisol. Glucose oxidation was higher in fasting state and post glucose load, while lipid oxidation was strongly reduced.Conclusion: An energy preservation mechanism seems to be the key element for normal-weight bulimic patients’ metabolism, consisting in leptin levels and GIT reduction, and lipid oxidation inhibition.