Efficacy and Safety of Inclisiran in Asian Patients: Results From ORION-18

Background

Management of low-density lipoprotein cholesterol (LDL-C) in Asia remains suboptimal, with ∼50% of patients who are treated with lipid-lowering therapies (LLTs) unable to achieve their guideline-recommended LDL-C goals. Asian-representative studies of the use of inclisiran are needed.

Objectives

The authors sought to evaluate the efficacy and safety of inclisiran in Asian patients with atherosclerotic cardiovascular disease (ASCVD) or high risk of ASCVD, as an adjunct to diet and maximally tolerated statin dose, with or without additional LLTs.

Methods

The ORION-18 was a phase 3 double-blind trial in which patients were randomized 1:1 to receive either 300 mg inclisiran sodium or matching placebo on days 1, 90, and 270. Percentage change in LDL-C from baseline to day 330 was the primary endpoint.

Results

A total of 345 patients (mean age 59.5 years, mean baseline LDL-C 109 mg/dL, 74.7% male) were randomized to inclisiran or placebo. Baseline characteristics were similar in both groups. The percentage decrease in LDL-C from baseline to day 330 was 57.2% (P < 0.001); proprotein convertase subtilisin/kexin type 9 was reduced by 78.3% (P < 0.001). Time-adjusted percentage reduction in LDL-C from baseline after day 90 and up to day 360 was 56.3%. At day 330, 71.7% of participants with inclisiran achieved ≥50% reduction in LDL-C compared with 1.5% with placebo. Over the study period, total cholesterol, apolipoprotein B, and non-high-density lipoprotein cholesterol (HDL-C) levels were decreased significantly, and HDL-C levels increased. The incidence of adverse events with inclisiran was similar to that with placebo.

Conclusions

In Asian patients with ASCVD or high risk of ASCVD, inclisiran was effective and safe. (Study of Efficacy and Safety of Inclisiran in Asian Participants With Atherosclerotic Cardiovascular Disease [ASCVD] or ASCVD High Risk and Elevated Low-Density Lipoprotein Cholesterol [LDL-C] [ORION-18]; NCT04765657).

Efficacy, Safety, and Tolerability of Inclisiran in Patients With Homozygous Familial Hypercholesterolemia: Results From the ORION-5 Randomized Clinical Trial

BACKGROUND

Homozygous familial hypercholesterolemia is a genetic disease characterized by extremely high levels of low-density lipoprotein cholesterol (LDL-C) and a high risk of premature cardiovascular events. The proof-of-concept study ORION-2 (A Study of Inclisiran in Participants With Homozygous Familial Hypercholesterolemia) showed that inclisiran, a small interfering RNA that prevents production of the hepatic PCSK9 protein (proprotein convertase subtilisin/kexin type 9), could lead to durable reductions in LDL-C levels when added to statins and ezetimibe in patients with homozygous familial hypercholesterolemia.

METHODS

ORION-5 was a phase 3, 2-part, multicenter study in 56 patients with homozygous familial hypercholesterolemia and elevated LDL-C levels despite maximum tolerated doses of LDL-C-lowering therapies with or without lipoprotein apheresis. Patients eligible for part 1 (double-blind, 6 months) were randomized 2:1 to receive either 300 mg of inclisiran sodium (equivalent to 284 mg of inclisiran) or placebo. Placebo-treated patients from part 1 were transitioned to inclisiran in part 2 (open-label, 18 months). The primary end point was the percentage change in LDL-C levels from baseline to day 150.

RESULTS

The mean age of the patients was 42.7 years, and 60.7% were women. The mean baseline LDL-C levels were 294.0 mg/dL and 356.7 mg/dL in the inclisiran and placebo groups, respectively. The placebo-corrected percentage change in LDL-C level from baseline to day 150 was -1.68% (95% CI, -29.19% to 25.83%; P=0.90), and the difference was not statistically significant between the inclisiran and placebo groups. The placebo-corrected percentage change in PCSK9 levels from baseline to day 150 was -60.6% with inclisiran treatment (P<0.0001); this was sustained throughout the study, confirming the effect of inclisiran on its biological target of PCSK9. No statistically significant differences between the inclisiran and placebo groups were observed in the levels of other lipids and lipoproteins (apolipoprotein B, total cholesterol, and non-high-density lipoprotein cholesterol). Adverse events and serious adverse events did not differ between the inclisiran and placebo groups throughout the study.

CONCLUSIONS

Inclisiran treatment did not reduce LDL-C levels in patients with homozygous familial hypercholesterolemia despite substantial lowering of PCSK9 levels. Inclisiran was well-tolerated, and the safety findings were consistent with previously reported studies and the overall safety profile.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03851705.

Efficacy, Safety, and Pharmacokinetics of Inclisiran in Japanese Patients: Results from ORION-15

AIM

To evaluate the efficacy, safety, and pharmacokinetics (PK) of inclisiran in Japanese patients with high cardiovascular risk and elevated low-density lipoprotein cholesterol (LDL-C).

METHODS

ORION-15 was a phase 2, double-blind, placebo-controlled randomized trial. Patients with hypercholesterolemia, including heterozygous familial hypercholesterolemia (HeFH), were randomized to inclisiran sodium 100, 200, or 300 mg, or placebo and dosed subcutaneously on Days 1, 90, and 270. T he primary endpoint was the percentage change from baseline to Day 180 to demonstrate the superiority of inclisiran vs. placebo. Patients who consented to the PK substudy had additional study procedures for blood collection and safety assessment.

RESULTS

Overall, 312 patients (mean age, 63.6 years; male, 74.4%; baseline LDL-C, 114.0 mg/dL) were randomized. Baseline characteristics were well balanced among the groups. At Day 180, inclisiran at all doses demonstrated significant LDL-C and proprotein convertase subtilisin/kexin type 9 (PCSK9) reductions (p＜0.0001 for both), which showed a dose-response relationship. The greatest reductions (LDL-C, 65.3%; PCSK9, 79.2%) were with inclisiran sodium 300 mg. At Day 180, ＞86% of the patients receiving inclisiran achieved the Japan Atherosclerosis Society 2017 lipid management targets compared to 8.9% for placebo. The mean (SD) plasma half-life for inclisiran was 6.8 (2.0)-7.6 (0.8) h. The incidence of adverse events with inclisiran was similar to that with placebo.

CONCLUSION

Inclisiran sodium 100, 200, and 300 mg demonstrated clinically meaningful and statistically significant LDL-C and PCSK9 reductions at Day 180, which were consistent over 12 months. Inclisiran was effective and well tolerated in Japanese patients with hypercholesterolemia, including HeFH.

Safety and Tolerability of Inclisiran for Treatment of Hypercholesterolemia in 7 Clinical Trials

BACKGROUND

Inclisiran is a small interfering RNA agent to lower low-density lipoprotein cholesterol.

OBJECTIVES

The purpose of this study was to provide reliable evidence to date on the long-term safety profile of inclisiran.

METHODS

This post hoc analysis comprised patients treated with 300 mg inclisiran sodium or placebo in the completed (ORION-1, -3, -5, -9, -10, and -11) and ongoing (ORION-8) trials. Exposure-adjusted incidence rates and Kaplan-Meier estimates of cumulative incidence of reported treatment-emergent adverse events (TEAE), abnormal laboratory measurements, and incidence of antidrug antibodies were analyzed.

RESULTS

This analysis included 3,576 patients treated with inclisiran for up to 6 years and 1,968 patients treated with placebo for up to 1.5 years, with 9,982.1 and 2,647.7 patient-years of exposure, respectively. Baseline characteristics were balanced between groups. Kaplan-Meier analyses showed that TEAEs that were serious or led to discontinuation; hepatic, muscle, and kidney events; incident diabetes; and elevations of creatine kinase or creatinine accrued at a comparable rate between groups for up to 1.5 years, with similar trends continuing for inclisiran beyond this period. Numerically fewer major cardiovascular events reported as TEAEs occurred with inclisiran during this period. Treatment-induced antidrug antibodies were uncommon with inclisiran (4.6%), with few of these persistent (1.4%) and not associated with greater incidence of TEAEs leading to study drug discontinuation or serious TEAEs.

CONCLUSIONS

Long-term treatment with inclisiran was well tolerated in a diverse population, without new safety signals, supporting the safety of inclisiran in patients with dyslipidemia.

Long-term efficacy and safety of inclisiran in patients with high cardiovascular risk and elevated LDL cholesterol (ORION-3): results from the 4-year open-label extension of the ORION-1 trial

INTRODUCTION

Whether long-term treatment with the twice-yearly, siRNA therapeutic inclisiran, which reduces hepatic production of proprotein convertase subtilisin/kexin type 9 (PCSK9), results in sustained reductions in LDL cholesterol with an acceptable safety profile is not known. The aim of this study was to assess the effect of long-term dosing of inclisiran in patients with high cardiovascular risk and elevated LDL cholesterol.

METHODS

ORION-3 was a 4-year open-label extension study of the placebo-controlled, phase 2 ORION-1 trial, conducted at 52 sites across five countries. Patients with prevalent atherosclerotic cardiovascular disease or high-risk primary prevention and elevated LDL cholesterol despite maximally tolerated statins or other LDL-lowering treatments, or with documented statin intolerance, who had completed the ORION-1 trial were eligible. Patients receiving inclisiran in ORION-1 received twice-yearly 300 mg subcutaneous inclisiran sodium throughout ORION-3 (inclisiran-only arm), whereas patients receiving placebo in ORION-1 first received subcutaneous evolocumab 140 mg every 2 weeks until day 360 thereafter transitioning to inclisiran twice-yearly for the remainder of ORION-3 study (switching arm). The primary efficacy endpoint was the percentage change in LDL cholesterol with inclisiran from the start of ORION-1 through to day 210 of the open label extension phase in the inclisiran-only arm (approximately 570 days of total inclisiran exposure in the modified intention-to-treat population). Secondary and exploratory endpoints included changes in LDL-C cholesterol and PCSK9 concentrations levels up to day 1440 (4 years) in each arm, and safety. ORION-3 is registered with ClinicalTrials.gov, NCT03060577.

FINDINGS

Of the original ORION-1 cohort of 497 patients, 290 of 370 patients allocated to drug continued into the inclisiran-only arm and 92 of 127 patients allocated to placebo entered the switching-arm in the ORION-3 extension study conducted between March 24, 2017, and Dec 17, 2021. In the inclisiran-only arm, LDL cholesterol was reduced by 47·5% (95% CI 50·7-44·3) at day 210 and sustained over 1440 days. The 4-year averaged mean reduction of LDL-C cholesterol was 44·2% (95% CI: 47·1-41·4), with reductions in PCSK9 ranging from 62·2% to 77·8%. Adverse events at the injection site were reported in 39 (14%) of 284 patients in the inclisiran-only arm and 12 (14%) of 87 patients in the switching arm. The incidence of treatment-emergent serious adverse events possibly related to the study drug was 1% (three of 284) in the inclisiran-only arm and 1% (one of 87) in the switching arm.

INTERPRETATION

Twice-yearly inclisiran provided sustained reductions in LDL cholesterol and PCSK9 concentrations and was well tolerated over 4 years in the extension study. This is the first prospective long-term study to assess repeat hepatic exposure to inclisiran.

FUNDING

Novartis Pharma.

Effects of Changing the Amount and Source of Dietary Carbohydrates on Symptoms and Dietary Satisfaction Over a 1-Year Period in Subjects with Type 2 Diabetes: Canadian Trial of Carbohydrates in Diabetes (CCD)

OBJECTIVES

To determine the long-term effects of changing the amount or source of dietary carbohydrate on quality of life (QOL), symptoms and dietary satisfaction in people with type 2 diabetes.

METHODS

Subjects with diabetes treated by diet alone (n=162) were randomly assigned to high-carbohydrate/high-glycemic-index (HGI) diets; high-carbohydrate/low-glycemic-index (LGI) diets; or lower-carbohydrate/high-monounsaturated-fat (LC) diets for 1 year. We measured QOL at baseline and at study's end, and we measured symptoms and dietary satisfaction quarterly.

RESULTS

The HGI, LGI and LC diets contained, respectively, 47±1, 52±1 and 40±1% energy carbohydrate; 30±1, 27±1 and 40±1% fat with GI 64±0.4, 55±0.4 and 59±0.4. Significantly more participants reported increased flatulence on LGI than on LC and HGI diets at 3 months (41%, 19%, 14%; p<0.05), but not at 12 months (29%, 17%, 17%; ns). Abdominal distension was more severe (46% vs. 14%, 19%; p<0.05), and headache less severe (8% vs. 22%, 23%; p<0.05) on LGI than on both other diets. Increased appetite was more severe on LC (33%) than on HGI diets (14%, p<0.05). Joint/limb pains were less severe on LGI (16%) than HGI (28%) diets. LC elicited more severe gloomy thoughts (23%) than LGI (4%; p<0.05) but greater dietary-satisfaction (70%; p<0.05) than LGI (40%) and HGI (48%) diets. For all diets, glycated hemoglobin (A1C) levels increased less in those who gained less weight, had less increased appetite and were more satisfied with the enjoyment obtained from eating.

CONCLUSIONS

Each diet elicited increased severity of 1 or more symptoms than the other diets. Although overall dietary satisfaction was greater on the 40% carbohydrate diet than on the 50% carbohydrate diet, the LGI diet was no less satisfying than the HGI diet. Changes in appetite and dietary satisfaction may influence body weight and glycemic control, or vice-versa.

Current level of glycaemic control and its associated factors in patients with type 2 diabetes across Europe: data from the PANORAMA study

OBJECTIVE

To provide an update on glycaemic control in European patients with type 2 diabetes based on data from the nine-country, cross-sectional PANORAMA study (NCT00916513).

DESIGN

Post-hoc analysis to report the number of patients achieving/not achieving glycaemic goal (HbA(1c) <7%).

PATIENTS

Patients were randomly or consecutively selected from physician practices in nine countries. Eligible patients were aged ≥40 years, diagnosed with type 2 diabetes >1 year prior to study entry, and had an available medical record of >1 year.

MEASUREMENTS

All data were collected at a single visit, including HbA1c measurement using a common device (A1CNow). Bivariate and multivariate analyses were used to investigate factors associated with not reaching glycaemic goal.

RESULTS

Of 5817 patients enrolled (aged 65·9 ± 10·4 years, 53·7% male), 37·4% had an HbA(1c) ≥7%; (range 25·9% in The Netherlands to 52·0% in Turkey). In adjusted multivariate analyses, higher individual glycaemic target, younger age, poor physician-reported patient adherence to lifestyle/medication, longer diabetes duration, increasing treatment regimen complexity and physician-reported patient's unwillingness to intensify treatment were associated with not achieving goal. However, bivariate analyses also found gender, socioeconomic factors, body mass index, rate of complications and hypoglycaemia to be associated with not achieving goal.

CONCLUSIONS

In PANORAMA, 37·4% of patients enrolled were not at glycaemic goal. Factors relating to patient characteristics, physician selection of individualized HbA1c target and diabetes itself (longer duration, more complex treatment) were strongly associated with not achieving goal. Further studies are warranted to explore these associations and evaluate strategies for improving glycaemic control.

Altering source or amount of dietary carbohydrate has acute and chronic effects on postprandial glucose and triglycerides in type 2 diabetes: Canadian trial of Carbohydrates in Diabetes (CCD)

BACKGROUND AND AIMS

Nutrition recommendations for type 2 diabetes (T2DM) are partly guided by the postprandial responses elicited by diets varying in carbohydrate (CHO). We aimed to explore whether long-term changes in postprandial responses on low-glycemic-index (GI) or low-CHO diets were due to acute or chronic effects in T2DM.

METHODS AND RESULTS

Subjects with diet-alone-treated T2DM were randomly assigned to high-CHO/high-GI (H), high-CHO/low-GI (L), or low-CHO/high-monounsaturated-fat (M) diets for 12-months. At week-0 (Baseline) postprandial responses after H-meals (55% CHO, GI = 61) were measured from 0800 h to 1600 h. After 12 mo subjects were randomly assigned to H-meals or study diet meals (L, 57% CHO, GI = 50; M, 44% CHO, GI = 61). This yielded 5 groups: H diet with H-meals (HH, n = 34); L diet with H- (LH, n = 17) or L-meals (LL, n = 16); and M diet with H- (MH, n = 18) or M meals (MM, n = 19). Postprandial glucose fluctuations were lower in LL than all other groups (p < 0.001). Changes in postprandial-triglycerides differed among groups (p < 0.001). After 12 mo in HH and MM both fasting- and postprandial-triglycerides were similar to Baseline while in MH postprandial-triglycerides were significantly higher than at Baseline (p = 0.028). In LH, triglycerides were consistently (0.18-0.34 mmol/L) higher than Baseline throughout the day, while in LL the difference from Baseline varied across the day from 0.04 to 0.36 mmol/L (p < 0.001).

CONCLUSION

Low-GI and low-CHO diets have both acute and chronic effects on postprandial glucose and triglycerides in T2DM subjects. Thus, the composition of the acute test-meal and the habitual diet should be considered when interpreting the nutritional implications of different postprandial responses.

Effects of saxagliptin added to sub-maximal doses of metformin compared with uptitration of metformin in type 2 diabetes: the PROMPT study

OBJECTIVE

The PROMPT study compared efficacy and tolerability of two treatment intensification strategies: adding saxagliptin or uptitrating metformin monotherapy, in patients with type 2 diabetes (T2D) and inadequate glycaemic control on a sub-maximal metformin dose.

RESEARCH DESIGN AND METHODS

In this double-blind, 24-week study, metformin-tolerant patients with T2D on metformin monotherapy were randomised to receive fixed-dose metformin 1500 mg/day, plus either add-on saxagliptin 5 mg/day (SAXA-MET) or a two-step metformin uptitration (MET-UP) to a maximum dose (2500 mg/day).

CLINICAL TRIAL REGISTRATION

NCT01006590.

MAIN OUTCOME MEASURES

Primary: absolute change from baseline in glycated haemoglobin A(1c) (HbA(1c)) (Week 24). Secondary: proportion of patients achieving a therapeutic glycaemic response (Week 24); change from baseline in fasting plasma glucose (Week 24); safety and tolerability. Exploratory analyses comprised three patient-related questionnaires, including the validated 5-dimension Digestive Health Status Index (DHSI).

RESULTS

A total of 286 patients were randomised: (SAXA-MET: 147; MET-UP: 139). Baseline mean (SD) HbA(1c): 7.71 (0.85; SAXA-MET); 7.80 (0.82; MET-UP). Adjusted mean reductions from baseline in HbA(1c) (Week 24): -0.47% (SAXA-MET); -0.38% (MET-UP); mean (95% CI) difference in treatment effect, -0.10% (-0.26, 0.07); p = 0.260. The proportion of patients (95% CI) achieving a therapeutic glycaemic response (HbA(1c) < 7%): 43.8% (34.8, 49.6) (SAXA-MET) vs. 35.0% (29.0, 43.8) (MET-UP). Of the five DHSI domains, mean (95% CI) differences were observed for diarrhoea-predominant score (+0.8 [-2.5, 4.0] vs. +7.9 [4.6, 11.2]) and dysmotility score (-0.5 [-2.0, 1.0] vs. +1.9 [0.3, 3.4]), (SAXA-MET and MET-UP, respectively). The most common adverse event was diarrhoea: 6.1% (SAXA-MET) vs. 12.2% (MET-UP).

CONCLUSIONS

In metformin-tolerant patients with T2D (inadequately controlled on sub-maximal metformin monotherapy), saxagliptin was well tolerated. Although HbA(1c) reduction was not significantly different between treatment groups, the lower occurrence of gastrointestinal symptoms in the SAXA-MET group suggests that saxagliptin add-on treatment may be a suitable alternative treatment strategy to metformin uptitration.

Efficacy and safety of saxagliptin in older patients with type 2 diabetes mellitus

OBJECTIVE

To assess the safety and efficacy of saxagliptin (5 mg once-daily) in older patients (≥65 years of age) with inadequately controlled type 2 diabetes.

RESEARCH DESIGN AND METHODS

In this retrospective subgroup analysis, data from five randomized, double-blind, placebo-controlled, multicenter, 24-week, phase 3 trials were included. The primary studies evaluated saxagliptin 5 mg once-daily (monotherapy or add-on) in patients aged 18-77 years with HbA(1c) ≥7.0% (four studies) or ≥7.5% (add-on to glyburide study) versus placebo.

MAIN OUTCOME MEASURES

The primary efficacy endpoint of each study included in this pooled analysis was HbA(1c) change from baseline to week 24.

RESULTS

In the five-study pooled population, 279 (16.6%) patients were at least 65 years old; 142 received saxagliptin 5 mg once-daily and 137 received placebo. Treatment groups were well-balanced for baseline characteristics within each study. In older patients, the HbA(1c) adjusted mean change from a baseline of 8.1% was -0.73 ± 0.16% (mean ± SEM) with saxagliptin compared with -0.17 ± 0.14% for placebo from a baseline of 8.0%. Adverse event rates were similar with saxagliptin 5 mg once-daily compared with placebo in older patients.

CONCLUSION

The pooled subgroup analysis of saxagliptin 5 mg once-daily monotherapy and add-on therapy trials demonstrated clinically relevant and significant efficacy for reducing HbA(1c) in older (≥65 years) patients. Saxagliptin was well-tolerated in older patients with a low incidence of hypoglycemia and no weight gain.

Low glycaemic index diet and disposition index in type 2 diabetes (the Canadian trial of carbohydrates in diabetes): a randomised controlled trial

AIMS/HYPOTHESIS

We recently found that oral glucose tolerance over 1 year in type 2 diabetic patients declined to a significantly lesser degree on a low-glycaemic-index than on a reduced-carbohydrate diet. Here, we examined whether that finding was associated with an improvement in disposition index, an index of beta cell function defined as the product of insulin sensitivity and insulin secretion. Since this is a report of secondary analysis on a previously published trial, the results should be considered as hypothesis-generating.

METHODS

Type 2 diabetic patients treated by diet alone (n = 162) were randomised by computer to high-carbohydrate/high-glycaemic index (High-GI, n = 52), high-carbohydrate/low-glycaemic index (Low-GI, n = 56) or low-carbohydrate/high-monounsaturated-fat (Low-CHO, n = 54) diets for 1 year in a multi-centre, parallel-design clinical trial conducted at University teaching hospitals. At baseline and at 3, 6 and 12 months participants underwent 75 g OGTTs; 27 participants dropped out or were excluded. Indices of insulin sensitivity, insulin secretion and disposition index, derived from the OGTT, were compared among diets. Those assessing the outcomes were blinded to group assignment.

RESULTS

Neither muscle insulin sensitivity index nor insulinogenic index differed significantly among diets. However, a significant time x diet interaction existed for disposition index (muscle insulin sensitivity index x insulinogenic index) (p = 0.036). After 3 months, disposition index tended to be higher on Low-CHO than on Low-GI diets, namely by 0.07 h(-1) (95% CI -0.04, 0.18). However, by 12 months this reversed and disposition index became higher on Low-GI than on Low-CHO, namely by 0.12 h(-1) (0.01, 0.23; p < 0.05, baseline disposition index 0.23 h(-1)). There were no important adverse effects associated with the treatments.

CONCLUSIONS/INTERPRETATION

These results suggest that, in patients with type 2 diabetes on diet alone, a Low-GI diet for 1 year increases disposition index, an index of beta cell function, compared with a Low-CHO diet.

The Canadian Trial of Carbohydrates in Diabetes (CCD), a 1-y controlled trial of low-glycemic-index dietary carbohydrate in type 2 diabetes: no effect on glycated hemoglobin but reduction in C-reactive protein

BACKGROUND

The optimal source and amount of dietary carbohydrate for managing type 2 diabetes (T2DM) are unknown.

OBJECTIVE

We aimed to compare the effects of altering the glycemic index or the amount of carbohydrate on glycated hemoglobin (HbA1c), plasma glucose, lipids, and C-reactive protein (CRP) in T2DM patients.

DESIGN

Subjects with T2DM managed by diet alone (n=162) were randomly assigned to receive high-carbohydrate, high-glycemic-index (high-GI), high-carbohydrate, low-glycemic-index (low-GI), or low-carbohydrate, high-monounsaturated-fat (low-CHO) diets for 1 y.

RESULTS

The high-GI, low-GI, and low-CHO diets contained, respectively, 47%, 52%, and 39% of energy as carbohydrate and 31%, 27%, and 40% of energy as fat; they had GIs of 63, 55, and 59, respectively. Body weight and HbA1c did not differ significantly between diets. Fasting glucose was higher (P=0.041), but 2-h postload glucose was lower (P=0.010) after 12 mo of the low-GI diet. With the low-GI diet, overall mean triacylglycerol was 12% higher and HDL cholesterol 4% lower than with the low-CHO diet (P<0.05), but the difference in the ratio of total to HDL cholesterol disappeared by 6 mo (time x diet interaction, P=0.044). Overall mean CRP with the low-GI diet, 1.95 mg/L, was 30% less than that with the high-GI diet, 2.75 mg/L (P=0.0078); the concentration with the low-CHO diet, 2.35 mg/L, was intermediate.

CONCLUSIONS

In subjects with T2DM managed by diet alone with optimal glycemic control, long-term HbA1c was not affected by altering the GI or the amount of dietary carbohydrate. Differences in total:HDL cholesterol among diets had disappeared by 6 mo. However, because of sustained reductions in postprandial glucose and CRP, a low-GI diet may be preferred for the dietary management of T2DM.

Adrenocortical dysregulation as a major player in insulin resistance and onset of obesity

The aim of this review is to explore the dysregulation of adrenocortical secretions as a major contributor in the development of obesity and insulin resistance. Disturbance of adipose tissue physiology is one of the primary events in the development of pathologies associated with the metabolic syndrome, such as obesity and type 2 diabetes. Several studies indicate that alterations in metabolism of glucocorticoids (GC) and androgens, as well as aldosterone in excess, are involved in the emergence of metabolic syndrome. Cross talk among adipose tissue, the hypothalamo-pituitary complex, and adrenal gland activity plays a major role in the control of food intake, glucose metabolism, lipid storage, and energy balance. Perturbation of this cross talk induces alterations in the regulatory mechanisms of adrenocortical steroid synthesis, secretion, degradation, and/or recycling, at the level of the zonae glomerulosa (aldosterone), fasciculata (GC and GC metabolites), and reticularis (androgens and androgen precursors DHEA and DHEAS). As a whole, these adrenocortical perturbations contribute to the development of metabolic syndrome at both the paracrine and systemic level by favoring the physiological dysregulation of organs responsive to aldosterone, GC, and/or androgens, including adipose tissue.

The TNF-alpha-238G > a single-nucleotide polymorphism protects against memory decline in older adults with type 2 diabetes

Inflammatory markers predict memory dysfunction in elderly patients, but their contribution to memory deficits in adults with Type 2 diabetes mellitus (T2DM) is less well understood. The present study determined whether specific single-nucleotide polymorphisms in the promoter region of tumor necrosis factor-alpha (TNF-alpha) predict verbal memory in older patients with T2DM. Immediate and delayed verbal memory were assessed using word list and paragraph recall tests in a cohort of subjects with T2DM during 2 sessions, separated by 48 weeks. The presence of the TNF-alpha-238A allele, which has been shown to decrease gene expression, consistently predicted better baseline performance and protected against memory decline over a period of 48 weeks. Therefore, inflammatory mediators may be important modulators of memory function in individuals with T2DM.

Genetic polymorphisms of tumor necrosis factor-alpha modify the association between dietary polyunsaturated fatty acids and fasting HDL-cholesterol and apo A-I concentrations

BACKGROUND

Heterogeneity in circulating lipid concentrations in response to dietary polyunsaturated fatty acids (PUFAs) may be due, in part, to genetic variations. Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that can induce hyperlipidemia and is known to be modulated by dietary PUFAs.

OBJECTIVE

The objective was to determine whether TNF-alpha genotypes modify the association between dietary PUFA intake and serum lipid concentrations.

DESIGN

The study involved 53 men and 56 women aged 42-75 y with type 2 diabetes. Dietary intakes were assessed with the use of a 3-d food record, and blood samples were collected to determine fasting serum lipids. DNA was isolated from blood for genotyping by polymerase chain reaction-restriction fragment length polymorphism for the TNF-alpha -238G-->A and -308G-->A polymorphisms.

RESULTS

PUFA intake was positively associated with serum HDL cholesterol in carriers of the -238A allele (beta = 0.06 +/- 0.03 mmol/L per 1% of energy from PUFAs; P = 0.03), but negatively associated in those with the -238GG genotype (beta = -0.03 +/- 0.01, P = 0.03) (P = 0.004 for interaction). PUFA intake was inversely associated with HDL cholesterol in carriers of the -308A allele (beta = -0.07 +/- 0.02, P = 0.002), but not in those with the -308GG genotype (beta = 0.02 +/- 0.02, P = 0.13) (P = 0.001 for interaction). A stronger gene x diet interaction was observed when the polymorphisms at the 2 positions (-238/-308) were combined (P = 0.0003). Similar effects were observed for apolipoprotein A-I, but not with other dietary fatty acids and serum lipids.

CONCLUSION

TNF-alpha genotypes modify the relation between dietary PUFA intake and HDL-cholesterol concentrations. These findings suggest that genetic variations affecting inflammation may explain some of the inconsistencies between previous studies relating PUFA intake and circulating HDL.

Tumor necrosis factor alpha -238G>A genotype alters postprandial plasma levels of free fatty acids in obese individuals with type 2 diabetes mellitus

Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that impairs insulin action and alters lipid metabolism. We investigated the effects of genetic polymorphisms of TNF-alpha on circulating biomarkers of insulin resistance and lipid metabolism during an 8-hour metabolic profile test and a 2-hour oral glucose tolerance test in subjects with type 2 diabetes mellitus. Subjects (N = 123) recruited were type 2 diabetic men (n = 56) and women (n = 67) aged 36 to 75 years with a body mass index of at least 25 kg/m(2). Blood samples were collected to determine postprandial changes in circulating lipid levels and biomarkers of insulin resistance. Subjects were genotyped by polymerase chain reaction-restriction fragment length polymorphism for the TNF-alpha -238G>A, -308G>A, and -863C>A polymorphisms. Compared with subjects who were homozygous for the -238G allele, carriers of the -238A allele had an altered ability to suppress postprandial free fatty acids as shown by an increased net incremental area under the curve (0.26 +/- 2.44 vs -1.33 +/- 2.71 mEq h(-1) L(-1), P = .002) during the 8-hour metabolic profile test. This effect was observed in obese (1.04 +/- 2.42 vs -1.68 +/- 2.70 mEq h(-1) L(-1), P = .0004) but not in non-obese (-0.63 +/- 2.20 vs -0.95 +/- 2.71 mEq h(-1) L(-1), P = .6) individuals. Among obese subjects, carriers of the -308A allele had greater insulin resistance as estimated by the homeostasis model assessment of insulin resistance index (4.36 +/- 2.83 vs 2.85 +/- 1.75, P = .01), but no differences were observed among non-obese subjects (2.19 +/- 1.24 vs 1.97 +/- 0.90, P = .6). Our findings suggest that the -238G>A and -308G>A polymorphisms of TNF-alpha alter circulating free fatty acids and insulin resistance in obese subjects with type 2 diabetes mellitus.

Quality of life in type 2 diabetes patients under intensive multitherapy

AIM

To assess the impact of an intensive multitherapy (IMT) on perceived quality of life (QOL), attitudes, knowledge and diabetes self-management in patients with poorly controlled type 2 diabetes.

METHODS

A 12-month randomized trial was conducted in 72 patients with type 2 diabetes, HbA1c>or=8%, blood pressure (BP)>130/80 mmHg and dyslipidemia. Subjects were assigned to the IMT or control group, each n=36. IMT consisted in monthly visits including clinical and biochemical assessment, education sessions on diet, physical exercise, medical management of diabetes and associated diseases and adjustments in medication. Control patients were under the care of their physicians. We developed and validated a diabetes-specific questionnaire assessing QOL, attitudes, knowledge, diabetes self-management and socio-demographic data for this study. Outcomes were measured at 0, 6 and 12 months.

RESULTS

Subjects were 54.8+/-8.1 years old (duration of diabetes: 10.3+/-7.2 years). At baseline, questionnaires showed no difference in QOL between groups. At 12 months, QOL improved significantly in the IMT group when compared to controls (+13.2+/-10.3/+5.6+/-13.2%, P=0.003), particularly with respect to the satisfaction scale (+25.3+/-13.9/+5.4+/-21.7%, P<0.001). QOL was not affected by complications or hypoglycaemic episodes. QOL scores improved in IMT subjects who began insulin therapy during the trial. Attitude scores, in the high normal range at baseline, did not change. Knowledge (+18.2+/-26.3/+8.9+/-30.4%, P=0.047) and diabetes self-management (+22.6+/-35.3/+6.8+/-20.1%, P<0.001) improved.

CONCLUSIONS

In poorly controlled subjects, QOL improved statistically despite the inherent constraints imposed by IMT.

Enalapril increases the local extravasation of macromolecules and nitric oxide synthase in pancreas of the fructose-fed insulin-resistant rat model

OBJECTIVES

Angiotensin-converting enzyme (ACE) inhibitors have been associated with an increased risk of acute pancreatitis. The pathogenesis of this condition remains unclear, but an activation of the kinin system and a resultant localized angioedema have been implicated in the initial step leading to acute pancreatic damage. The goal of the present study was to explore the impact of ACE inhibition on pancreatic microcirculation and capillary permeability in normal and insulin-resistant rats.

METHODS

Chow- or fructose-fed Sprague-Dawley rats were treated with enalapril (dosage, 10 mg.kg.d) or vehicle for 4 weeks before measuring in vivo the extravasation of Evans blue (EB) dye in pancreas. Unanesthetized animals (n = 10-17 per group) were injected with EB 20 mg.kg in the caudal vein 10 minutes before killing, and EB dye was extracted from each pancreas by using formamide.

RESULTS

Relative to controls, enalapril-treated animals showed a 5-fold increase in pancreatic extravasation of EB in the fructose-fed rat model (P < 0.001); smaller changes (2-fold) were observed in the chow-fed animals treated with enalapril (P < 0.001). The increase in pancreatic vasopermeability observed with enalapril in the fructose-fed animals was accompanied by a significant increase in total pancreatic nitric oxide synthase (NOS) activity compared to controls (Delta = +128%; P < 0.001). This increase in NOS activity seemed to be solely attributable to an upregulation of the endothelial NOS isoform because only the eNOS immunoreactive mass (as opposed to nNOS) seemed to be increased in the pancreas of these animals. Treatment with enalapril was not associated with any increase in serum amylase concentrations in either animal subgroup.

CONCLUSIONS

Enalapril increases capillary permeability (extravasation of macromolecules) in the pancreas of the fructose-fed rat model. This suggests that ACE inhibition upregulates the eNOS isoform locally, increases vasopermeability of the pancreas, and can therefore result in local edema in the fructose-fed insulin-resistant rat model.

Surveillance and treatment of dyslipidemia in the post-infarct patient: can a nurse-led management approach make a difference?

BACKGROUND

Lowering plasma lipid levels in patients in the months following hospital discharge for a myocardial infarction (MI) is clearly beneficial if recurrent cardiac events and mortality are to be prevented; traditionally, however, there has been a large gap between guidelines and levels achieved in routine practice.

OBJECTIVES AND METHODS

A randomized, open-label clinical trial was conducted to assess the impact of nurse-centred surveillance and treatment in achieving nationally recognized lipid targets in post-MI patients. This program had the following features: systematic telephone follow-up of patients discharged from the University of Sherbrooke (Sherbrooke, Quebec) after an MI; systematic lipid testing three months after discharge; close liaison with, and guidance of, patients' primary care physicians to intervene on results of this test if targets were not obtained; and continued monitoring of patients until lipid profiles consistent with consensus targets were achieved. The impact of this approach was tested and compared with that of a control group that continued to be followed by a primary care physician for up to 18 months.

RESULTS

A total of 127 patients were randomly assigned into an intervention group (n=64) or a control group (n=63). The intervention group was followed by telephone for an average (+/-SD) of 4.4+/-2.0 months post-MI. At this point, when intervention was optimized, the mean low-density lipoprotein cholesterol (LDL-C) level was 2.19+/-0.65 mmol/L in the intervention group, and 87.3% of patients had LDL-C levels of less than 2.5 mmol/L. Patients from both experimental groups returned at 12 months and 18 months post-MI for a new blood lipid assessment. In total, 12.5% of patients in each group were lost to follow-up. At 12 months and 18 months, the mean LDL-C level was not different between the two groups, nor was there a significant difference in the proportion of patients achieving LDL-C levels of less than 2.5 mmol/L (51.6% in the intervention group and 65% in the control group at 18 months; P>0.05). When the combined end point of an LDL-C level of less than 2.5 mmol/L, a triglyceride level of less than 2.0 mmol/L and a total cholesterol to high-density lipoprotein cholesterol ratio of less than 4.0 was considered, the proportion of patients achieving this composite at 18 months was low and not different between the two groups (23.4% in the intervention group and 38.3% in the control group; P>0.05). Over 95% of patients in both groups were on a lipid-lowering medication, and more than 90% had complied with their medication regimen at 18 months.

CONCLUSIONS

This trial did not support the role of nurse-managers and a system of telephone-based contacts to ensure the continuity of care and aggressive intervention when considering cardiovascular risk factors in post-MI patients. This trial also re-emphasized the important remaining treatment gap in secondary prevention of coronary artery disease, particularly if composite lipid end points are to be targeted.

Increased extravasation of macromolecules in skeletal muscles of the Zucker rat model

OBJECTIVE

Assess whether changes in permeability of the muscle regional microcirculation occur in the obese Zucker rat model.

RESEARCH METHODS AND PROCEDURES

Capillary permeability to albumin was assessed in vivo in Zucker rats (n = 15) and lean controls (n = 15) by quantifying the extravasation of albumin-bound Evans Blue (EB) in different organs. Unanaesthetized animals were injected with EB 20 mg/kg in the caudal vein, and EB was extracted by formamide from selected organs collected after exsanguination.

RESULTS

Relative to control animals, Zucker rats had higher body weight (Delta = +33%; p < 0.001), plasma triglycerides (Delta = +244%; p < 0.001), and insulin (Delta = +240%; p < 0.001) concentrations. Plasma glucose concentrations were not different between the two groups (p = not significant). Using the EB technique, we showed a 30% to 50% (p < 0.01) increase in the extravasation of EB in the obese rats, regardless of the skeletal muscle group studied. This increase in skeletal muscle vasopermeability was not paralleled by any increase in the expression of the muscle endothelium-nitric oxide (NO) system because the total NO synthase (NOS) activity in skeletal muscle of the obese Zucker rat was significantly lower (p < 0.001), as was the endothelial NOS immunoreactive mass (p < 0.001), compared with lean controls.

DISCUSSION

In conclusion, there seems to be dissociation between capillary permeability and local regulation of microcirculation in skeletal muscles of the obese Zucker rat. It is suggested that the increase in skeletal muscle vasopermeability (extravasation of macromolecules) is a compensation for the loss of NO-dependent vasodilation and capillary recruitment noted in this model of obesity and insulin resistance.

Efficacy of intensive multitherapy for patients with type 2 diabetes mellitus: a randomized controlled trial

BACKGROUND

National guidelines for managing diabetes set standards for care. We sought to determine whether a 1-year intensive multitherapy program resulted in greater goal attainment than usual care among patients with poorly controlled type 2 diabetes mellitus.

METHODS

We identified patients with poorly controlled type 2 diabetes receiving outpatient care in the community or at our hospital. Patients 30-70 years of age with a hemoglobin A1c concentration of 8% or greater were randomly assigned to receive intensive multitherapy (n = 36) or usual care (n = 36).

RESULTS

The average hemoglobin A1c concentration at entry was 9.1% (standard deviation [SD] 1%) in the intensive therapy group and 9.3% (SD 1%) in the usual therapy group. By 12 months, a higher proportion of patients in the intensive therapy group than in the control group had achieved Canadian Diabetes Association (CDA) goals for hemoglobin A(1c) concentrations (goal < or = 7.0%: 35% v. 8%), diastolic blood pressure (goal < 80 mm Hg: 64% v. 37%), low-density lipoprotein cholesterol (LDL-C) levels (goal < 2.5 mmol/L: 53% v. 20%) and triglyceride levels (goal < 1.5 mmol/L: 44% v. 14%). There were no significant differences between the 2 groups in attaining the targets for fasting plasma glucose levels, systolic blood pressure or total cholesterol:high-density lipoprotein cholesterol ratio. None of the patients reached all CDA treatment goals. By 18 months, differences in goal attainment were no longer evident between the 2 groups, except for LDL-C levels. Quality of life, as measured by a specific questionnaire, increased in both groups, with a greater increase in the intensive therapy group (13% [SD 10%] v. 6% [SD 13%], p < 0.003).

INTERPRETATION

Intensive multitherapy for patients with poorly controlled type 2 diabetes is successful in helping patients meet most of the goals set by a national diabetes association. However, 6 months after intensive therapy stopped and patients returned to usual care, the benefits had vanished.

Rosiglitazone increases extravasation of macromolecules and endothelial nitric oxide synthase in skeletal muscles of the fructose-fed rat model

Reduced extravasation of macromolecules in skeletal muscle has recently been documented in the fructose-fed rat model, corroborating a hypothesis that a functional obliteration of muscle regional microcirculation might lead to hypertension and restrict access of nutrients and hormones to their target cells. The goal of this study was to assess the impact of a treatment with rosiglitazone on the reduced muscle vasopermeability observed previously in the fructose-fed rat model. Fructose-fed Sprague-Dawley rats were gavaged with rosiglitazone (10 micromol kg(-1) per day; n = 21) or the vehicle only (n = 19) for 3 consecutive weeks before assessing the extravasation of Evans Blue (EB) dye in vivo in distinct muscle groups. Relative to control group, rosiglitazone reduced mean arterial blood pressure (Delta = -16.7%, P < 0.001), plasma insulin (Delta= -39.1%, P < 0.05) and plasma triglyceride (Delta= -32.8 %, P < 0.01) concentrations in a significant manner. Plasma VEGF concentrations were significantly lower in the rosiglitazone-treated animals compared to the control animals (32.7 +/- 0.8 pg ml(-1) versus 46.1 +/- 1.2 pg ml(-1), P < 0.001). While no changes were observed in the lungs or the kidneys, fructose-fed rats treated with rosiglitazone had a 30-50% increase (P < 0.005) in the extravasation of EB regardless of the skeletal muscle group studied (rectus femoris, soleus, gastrocnemius lateralis, vastus lateralis and tibialis cranalis). In homogenates of skeletal muscles (vastus lateralis) of fructose-fed rats, rosiglitazone resulted in a significant increase in NO synthase (NOS) activity (Delta = +41.9 %, P < 0.003) as well as endothelial NOS immunoreactive mass (Delta = +37.8 %, P < 0.01) compared to the control animals. There was no change in the immunoreactive level of the nNOS isoform, the most abundant muscle isoform, or in the immunoreactive levels of VEGF. In conclusion, rosiglitazone appears to restore a vascular dysfunction previously documented in the skeletal muscle microcirculation, as evidenced by improved skeletal muscle vasopermeability and upregulation of the muscle endothelium-NO system in the fructose-fed rat model. These effects on muscle per se might also result in a partial improvement of the insulin resistance phenomenon by improving the distribution of nutrients and insulin to skeletal muscle. This effect appears to be independent of circulating levels of VEGF since changes in plasma concentrations of this permeability factor were lower in the rosiglitazone-treated group.

Reduction of endothelial NOS and bradykinin-induced extravasation of macromolecules in skeletal muscle of the fructose-fed rat model

OBJECTIVE

Reduced capillary permeability of the skeletal muscle vascular bed has been suggested to play a role in fructose-fed rats, corroborating a long held view that insulin resistance might partially be explained by the lack of access of insulin and glucose to its target organs, mainly skeletal muscles. The goal of this study was to explore mechanisms underlying this vascular abnormality, and more specifically the role of bradykinin and nitric oxide (NO) on skeletal muscle microcirculation and the extravasation of macromolecules.

METHODS

For that purpose, Sprague-Dawley rats were fed with either a fructose-enriched (F) or a normal chow (N) diet and extravasation of macromolecules was assessed at 4 weeks by measuring in vivo the extravasation of Evans Blue (EB) dye in the quadriceps muscles of both groups after the intravenous injection of the potent vasodilator bradykinin (150 microg/kg).

RESULTS

As expected, fructose-fed rats had less extravasation of EB in skeletal muscle in the basal state as compared to controls (F 17.6 +/- 4.4 vs. N 43.6 +/- 6.9 microg/g dry tissue; P<0.01). In response to bradykinin, the EB dye extravasation in skeletal muscle was 89.4% higher in rats fed the normal chow diet compared to the basal state (P<0.03). In contrast, no significant increase in vasopermeability was observed in fructose-fed animals acutely injected with BK (17.6 +/- 4.4 microg/g in the basal state versus 24.6 +/- 3.1 microg/g after the injection of BK; P=NS). To distinguish a functional from an anatomical/structural defect, hematoxylin-eosin sections as well as electron micrographs of skeletal muscle microvessels were examined in both groups of animals: no obvious abnormalities were found. However, in homogenates of skeletal muscles (quadriceps) of fructose-fed rats, there was a marked reduction of NO synthase (NOS) activity (-33.8%; P<0.001) as well as endothelial NOS immunoreactive mass (-23.4%; P<0.04) as compared to control animals.

CONCLUSION

There is unresponsiveness of the skeletal muscle capillary bed to bradykinin in insulin-resistant animals most probably due to a reduction in endothelial NOS (activity and mass). Our results indicate a functional defect possibly involving responsiveness of the precapillary resistance and/or the endothelial barrier to bradykinin in skeletal muscles. Since insulin must cross the endothelial monolayer to reach its target cells on the abluminal side, it is suggested that reduced endothelial NOS and consequent reduced extravasation of macromolecules could exacerbate insulin resistance in skeletal muscles and hypertension in the fructose-fed rat.

An observational study comparing 2-hour 75-g oral glucose tolerance with fasting plasma glucose in pregnant women: both poorly predictive of birth weight

BACKGROUND

The definition and treatment of glucose intolerance during pregnancy are matters of intense controversy. Our goal was to examine the value of the 75-g oral glucose tolerance test (OGTT) in terms of its ability to predict birth weight percentile in a group of women with singleton pregnancies who received minimal treatment for their glucose intolerance.

METHODS

We reviewed the results of OGTTs performed between 24 and 28 weeks' gestation in a group of 300 consecutive high-risk women (mean age 29.5 years [95% confidence interval, CI, 28.9-30.1]; parity 1.5 [95% CI 1.4-1.7]) whose plasma glucose level 1 hour after a randomly administered 50-g glucose load was 8.0 mmol/L or above. These data were compared with results for a randomly selected control group of 300 women whose plasma glucose level 1 hour after a 50-g glucose load was less than 8.0 mmol/L (mean age 28.0 years [95% CI 27.4-28.6]; parity 1.5 [95% CI 1.3-1.6]).

RESULTS

For 76 (25.3%) of the 300 high-risk women, the plasma glucose level 2 hours after a 75-g glucose load (confirmatory OGTT) was 7.8 mmol/L or more, but only 6 of these were treated with insulin, which emphasizes the low level of intervention in this group. Thirty (10.0%) of the neonates in this group were large for gestational age (LGA; adjusted weight at or above the 90th percentile). This proportion did not significantly differ from the proportion for the control group (25 or 8.3%). After exclusion of the 6 insulin-treated women, simple correlations between birth weight percentile and fasting or 2-hour plasma glucose levels were very weak (r = 0.23 and 0.16 respectively; p < 0.01). The correlation between birth weight percentile and fasting or 2-hour plasma glucose persisted in a multiple regression analysis that included the following maternal variables: age, prepregnancy weight, weight gain during pregnancy, parity and smoking. In the multivariate models, the standardized coefficients for fasting and 2-hour plasma glucose levels were low (r = 0.19 [p < 0.001] and r = 0.13 [p = 0.02] respectively). These multivariate models could not explain more than 22% of the total variability in birth weight percentile.

INTERPRETATION

In this population of pregnant, untreated diabetic women, plasma glucose levels (either fasting or after various glucose loads) were independently but poorly correlated with birth weight; no more than 3% to 5% of birth weight variability could be explained by changes in glucose tolerance. Fasting plasma glucose was consistently but marginally better than the plasma glucose level 2 hours after 75-g glucose load for predicting LGA neonates. We conclude that neonatal macrosomia is influenced by variables that are largely independent of plasma glucose concentrations.

Acarbose in the treatment of elderly patients with type 2 diabetes

AIMS

To study the effect of acarbose, an alpha-glucosidase inhibitor, on glycemic control in elderly patients with type 2 diabetes.

METHODS

Elderly patients with type 2 diabetes treated with diet alone were randomly treated in a double-blind fashion with placebo (n=99) or acarbose (n=93) for 12 months.

RESULTS

After 12 months of therapy, there was a statistically significant difference in the change in glycated haemoglobin (HbA(1c)) (-0.6%) in the acarbose group versus placebo, as well as in the incremental post-prandial glucose values (-2.1 mmol h/l) and mean fasting plasma glucose (-0.7 mmol/l). Although there was no effect of acarbose on insulin release, there was a clear effect of acarbose to decrease relative insulin resistance (-0.8) (HOMA method). In addition, acarbose was generally well tolerated and safe in the elderly; most discontinuations were due to gastrointestinal side effects such as flatulence and diarrhea. There were no cases of hypoglycemia reported, and no clinically relevant changes in laboratory abnormalities or vital signs during the study.

CONCLUSIONS

Acarbose improves the glycemic profile and insulin sensitivity in elderly patients with type 2 diabetes who are inadequately controlled on diet alone.

Bradykinin B2 receptor gene polymorphism is associated with altered urinary albumin/creatinine values in diabetic patients

Diabetic nephropathy (DN) is an important microvascular complication of both insulin-dependent and non-insulin-dependent diabetes mellitus. Considerable evidence exists that genetic predisposition is a major determinant in the development of DN. Progress in the understanding of the kinin receptor gene expression indicates their relevance in nephrology and renal pathology. In order to investigate whether clinically relevant polymorphisms of the kinin receptor genes contribute to the genetic predetermination of the renal complication of diabetes, we have initiated a retrospective study with a mixed population of 49 type 1 and 112 type 2 diabetic patients who have been followed for several years by an endocrinologist and (or) nephrologist with periodical functional tests relevant to DN (microalbuminuria, serum and urinary creatinine). The allelic frequencies of four kinin receptor polymorphisms, including three B2R polymorphisms (the C/T-58 promoter polymorphism, the exon 2 and exon 1 polymorphisms, all of them with assumed clinical significance) and the putative nephroprotective (G/C-699) B1R promoter polymorphism, were analyzed in all recruited diabetic patients. Our results indicate a significant association of the B2R exon 1 (+/-) genotype with increased urinary albumin/creatinine values (P = 0.026) and serum creatinine levels (P = 0.028). More importantly, the (+) allele of B2R exon 1 polymorphism was associated very significantly with lower albumin/creatinine values in these patients (P = 0.0087). Thus, the B2R exon 1 polymorphism may represent a susceptibility marker for nephropathy progression in diabetic patients.

Insulin resistance affects the regulation of lipoprotein lipase in the postprandial period and in an adipose tissue-specific manner

AIMS

Insulin is a potent stimulator of adipose tissue lipoprotein lipase (LPL). Logically, the postprandial period is therefore a privileged time of the day for the regulation of LPL by insulin in this tissue. It is not clear to what extent a defect such as insulin resistance could affect this regulation and contribute to postprandial, as well as fasting, hypertriglyceridaemia. The aim of the present protocol was to study the relationship between insulin resistance and LPL in adipose tissue and in plasma, in the particular context of the postprandial period.

METHODS

For this study, 26 adult nondiabetic individuals (12 women and 14 men) with a wide range of whole-body insulin-mediated glucose uptake (as assessed with an insulin suppression test) were studied. An abdominal subcutaneous fat biopsy on one occasion, and post-heparin plasma on another occasion, were obtained 4 h into a standardized meal profile administered in the fasting state.

RESULTS

Postprandial triglyceride excursions (evaluated by the incremental area under the curve during the metabolic meal profile) were inversely correlated to adipose tissue LPL mRNA levels (rho = -0.43, P < 0.03) as well as to adipose tissue LPL heparin-releasable activity (rho = -0.58, P < 0.01). Steady-state plasma glucose (SSPG) concentrations during the insulin suppression test, a reflection of the degree of insulin resistance, were also negatively correlated to adipose tissue LPL mRNA (rho = -0.50, P < 0.02) and activity (rho = -0.56, P < 0.01). There was no correlation between plasma post-heparin LPL activity/mass and postprandial triglycerides nor with insulin resistance.

CONCLUSION

Regulation of adipose tissue LPL is significantly affected in insulin-resistant individuals in the postprandial period. This presumed impaired effect of insulin on LPL postprandially could be an important contributor to the atherogenic dyslipidaemia described in insulin resistance syndrome.

Induction of cholesteryl ester transfer protein in adipose tissue and plasma of the fructose-fed hamster

Cholesteryl ester transfer protein (CETP) plays a pivotal role in the reverse transport of cholesterol and in the remodeling of circulating lipoproteins. While plasma and adipose tissue levels of CETP are affected by a variety of metabolic conditions, the extent of the effects of dietary factors, other than high cholesterol feeding, are not well understood. To further explore this paradigm, male Golden Syrian hamsters were fed for 4 weeks with a 60%-enriched fructose diet (F) and were compared to a matched group of animals fed with a normal chow diet (N). After feeding for 4 weeks, plasma insulin concentrations were lower in animals fed fructose than in control animals (F: 3.3+/-0.8 vs N: 7.4+/-1.9 ng/mL; p<0.03), but there was no significant difference in plasma glucose concentrations between the two groups (F: 138+/-7 vs N: 148+/-10 mg/dL; p>0.05). Fructose-fed animals showed significant increases in plasma triglyceride (F: 269+/-22 vs N: 165+/-22 mg/dL; p<0.01) and plasma cholesterol (F: 150+/-10 vs N: 113+/-6 mg/dL; p<0.02) concentrations compared with control animals. Total CETP activity and immunoreactive mass were higher in the plasma of fructose-fed animals that in that of controls (F: 1036+/-70 vs N: 826+/-43 pmol/h/mL, p<0.04 and F: 24.5+/-3.1 vs N: 37.5+/-4.3 AU, p<0.02, respectively). Adipose tissue CETP mRNA levels, assessed by the very sensitive ribonuclease protection assay, were 53% higher in fructose-fed animals than in controls (F: 14.1+/-2.0 vs N: 9.2+/-1.0 AU over a rRNA control; p<0.04). Adipose tissue CETP activity and immunoreactive mass also showed a statistically significant increase in the fructose-fed hamsters compared with those fed a normal diet (p<0.04). In conclusion, fructose feeding in Syrian hamsters induces a mixed dyslipidemia. These metabolic changes are accompanied by a significant increase in CETP levels, both in plasma and in adipose tissue. This phenomenon suggests that the increase in the expression of adipose tissue CETP may be caused either by the ambient hypercholesterolemia resulting from fructose feeding or by an attenuation of a possible inhibitory effect of plasma insulin concentrations on the expression of adipose tissue CETP in this feeding paradigm.

Lipoprotein lipase steady-state mRNA levels are lower in human omental versus subcutaneous abdominal adipose tissue

Adipose tissue synthesizes lipoprotein lipase (LPL), which helps in the postprandial clearance of triglyceride-rich lipoproteins. Because visceral adipose tissue is generally accepted as the most important metabolic tissue, we sought to verify whether there are regional differences in the expression of LPL. Samples of adipose tissue from subcutaneous and omental fat deposits were obtained from 20 adults undergoing surgery. Total adipose tissue LPL activity was measured using a conventional radioactive substrate assay. Steady-state levels of LPL mRNA were assessed using the very sensitive RNase protection assay technique with 18S ribosomal RNA as an internal control. A correlation was demonstrated between LPL activity levels in subcutaneous and omental tissue (r = .72; P < .01) and between mRNA levels at both sites (r = .47, P = .04). LPL mRNA levels were significantly lower in omental compared with subcutaneous depots (omental v subcutaneous, 1.7 +/- 0.7 v 2.1 +/- 0.7 arbitrary units [AU] over 18S, P < .05). In paired comparisons, LPL mRNA levels in omental adipose tissue were, on average, 20% +/- 7% (range, -57% to +9.0%) lower than the levels measured in subcutaneous adipose tissue (P < .05). In conclusion, these data suggest that subcutaneous adipose tissue is a reliable surrogate of the expression (activity and mRNA) of LPL in omental adipose tissue, even though omental depots express proportionally less LPL than subcutaneous depots.

Effect of acarbose on insulin sensitivity in elderly patients with diabetes

OBJECTIVE

To study the effect of acarbose, an alpha-glucosidase inhibitor, on insulin release and insulin sensitivity in elderly patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Elderly patients with type 2 diabetes were randomly treated in a double-blind fashion with placebo (n = 23) or acarbose (n = 22) for 12 months. Before and after randomization, subjects underwent a meal tolerance test and a hyperglycemic glucose clamp study designed to measure insulin release and sensitivity.

RESULTS

After 12 months of therapy there was a significant difference in the change in fasting plasma glucose levels (0.2 +/- 0.3 vs. -0.5 +/- 0.2 mmol/l, placebo vs. acarbose group, respectively; P < 0.05) and in incremental postprandial glucose values (-0.4 +/- 0.6 vs. -3.5 +/- 0.6 mmol/l, placebo vs. acarbose group, P < 0.001) between groups. There was a significant difference in the change in HbA(1c) values in response to treatment (0.4 +/- 0.2 vs. -0.4 +/- 0.1%, placebo vs. acarbose group, P < 0.01). The change in fasting insulin in response to treatment (-2 +/- 2 vs. -13 +/- 4 pmol/l, placebo vs. acarbose group, P < 0.05) and incremental postprandial insulin responses (-89 +/- 26 vs. -271 +/- 59 pmol/l, placebo vs. acarbose group, P < 0.01) was also significantly different between groups. During the hyperglycemic clamps, glucose and insulin values were similar in both groups before and after therapy However, there was a significant difference in the change in insulin sensitivity in response to treatment between the placebo and the acarbose groups (0.001 +/- 0.001 vs. 0.004 +/- 0.001 mg/kg x min(-1) [pmol/l](-1), respectively, P < 0.05)

CONCLUSIONS

Acarbose increases insulin sensitivity but not insulin release in elderly patients with diabetes.

Evaluation of postural stability in elderly with diabetic neuropathy

OBJECTIVE

The objective of this study was to compare clinical and biomechanical characteristics of balance in diabetic polyneuropathic elderly patients and normal age-matched subjects.

RESEARCH DESIGN AND METHODS

Fifteen elderly with distal neuropathy (DNP) and 15 healthy age-matched subjects were evaluated with the biomechanical variable COP-COM, which represents the distance between the center of pressure (COP) and the center of mass (COM). Measurements were taken in the quiet position with a double-leg stance, in eyes-open (EO) and eyes-closed (EC) conditions. Subjects were also assessed with clinical balance evaluations.

RESULTS

The COP-COM variable was statistically significantly larger in the DNP group than in the healthy group in anterior-posterior (A/P) and medial-lateral (M/L) directions. Furthermore, the DNP group showed statistically significantly larger amplitudes of the COP-COM variable without vision. The severity of the neuropathy, as quantified using the Valk scoring system, was correlated with COP-COM amplitude in both directions.

CONCLUSIONS

Evaluation of the postural stability of an elderly diabetic population using the COP-COM variable can detect a very small change in postural stability and could be helpful in identifying elderly with DNP at risk of falling.

The degree of hyperinsulinemia and impaired glucose tolerance predicts plasma leptin concentrations in women only: a new exploratory paradigm

Plasma leptin has been shown to correlate positively with many indices of obesity, as well as insulin resistance. For a given body weight, the levels are higher in women than in men, but the reasons for this difference are not clear. Insulin has been shown to stimulate leptin production by adipose tissue in vivo and in vitro. Previous studies have reported that leptin levels are similar in diabetic and nondiabetic individuals. However, these studies were not performed in newly diagnosed diabetics, and other variables (such as gender) could have confounded the results. Therefore, the goal of the present cross-sectional study is to examine the effect of metabolic variables (such as glucose and insulin) on plasma leptin concentrations in men and women separately. We measured leptin levels in 48 subjects (17 with newly diagnosed type 2 diabetes mellitus, 13 with impaired glucose tolerance [IGT], and 18 normal individuals). The 3 groups were well matched for gender, age, and body mass index (BMI). When adjusted for the BMI and gender, a statistically significant gender-related difference in mean plasma leptin was observed across the 3 glucose tolerance subgroups (P < .03 by analysis of covariance [ANCOVA]). More specifically, plasma leptin levels were, on average, 44% lower in women with diabetes or IGT versus normal women (P < .02). No such between-group difference was observed in the men. In univariate analysis in the same female subgroup, plasma leptin correlated positively with fasting insulin (rs = +.43, P < .06) and negatively with 2-hour post-75-g glucose load plasma glucose concentration (rs = -.54, P < .02). In a multiple regression model controlling for the BMI in the female subgroup, circulating insulin and glucose concentrations 2 hours after the 75-g glucose load were good predictors of fasting plasma leptin (r = +.38, P = .02 and r = -.70, P < .001, respectively). Leptin levels in women appear to be influenced independently and to an important degree by ambient plasma glucose and plasma insulin concentrations. These findings suggest that the synthesis of leptin by adipose tissue is more susceptible to in vivo regulation by insulin and glucose in women than in men. Plasma leptin concentrations were also lower in women with IGT or type 2 diabetes versus normal women, suggesting that fasting and/or postprandial hyperglycemia interferes with the stimulatory effect of plasma insulin on the synthesis of leptin by adipose tissue in women only.

Pigmented adrenal hyperplasia with myelolipomatous changes and bilateral testicular enlargement in an untreated man with 21-hydroxylase deficiency

OBJECTIVE

To report the occurrence of a giant left adrenal tumor and bilateral testicular masses (adenomatous hyperplasia of Leydig cells) in a young man with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

METHODS

The clinical, radiologic, endocrinologic, and pathologic features of this case are correlated with the findings in the literature.

RESULTS

The interesting elements in this case are the rare pathologic features of the left adrenal lesion (pigmented adrenal hyperplasia with myelolipomatous changes) and the association with the infrequent testicular adrenal rest tumors. The absence of enlargement of the right adrenal gland was unexplained.

CONCLUSION

The presence of these two rare complications seemed to be associated with poor adherence to medical treatment recommendations for congenital adrenal hyperplasia.

Effects of gliclazide versus metformin on the clinical profile and lipid peroxidation markers in type 2 diabetes

The sulfonylurea gliclazide and the biguanide metformin have different mechanisms to reduce glycemia. We performed a randomized study to compare these two agents with respect to glycemic control and effects on lipid peroxidation markers in 36 adult patients with type 2 diabetes. Both agents significantly decreased glycosylated hemoglobin ([HbA1c] P < .05), fructosamine (P < .05), and the glucose-excursion curve during the oral glucose tolerance test ([OGTT] P < .01). With regard to the insulin curve during this test, no significant change was observed with metformin and a significant increase was measured with gliclazide (P < .05). Considering the small number of events, no significant difference was detected in the number of hypoglycemic episodes between the two agents. More upper-gastrointestinal (GI) symptoms were observed with metformin compared with gliclazide (P < .05). Even with no change in the standard lipid profile, both agents increased serum vitamin E (P < .01 for gliclazide and P < .05 for metformin) and decreased the level of lipid peroxidation markers in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles (P < .05). Despite different mechanisms of action, gliclazide and metformin demonstrated comparable levels of efficacy and complementary effects on lipid peroxidation markers.

Preoperative localization of parathyroid lesions in hyperparathyroidism: relationship between technetium-99m-MIBI uptake and oxyphil cell content

The aim of this study was to assess the relationship between parathyroid oxyphil cell content and early or late phases of uptake of 99mTc-MIBI, a radioisotope preferentially retained in mitochondria-rich cells.

METHODS

This study is a retrospective, single-blind analysis of all double-phase 99mTc-MIBI parathyroid scintigraphy studies performed before surgery in our institution between 1990 and 1995. A total of 18 parathyroid lesions in 14 patients were reviewed. This sample included 11 cases of primary hyperparathyroidism (8 adenomas, 1 adenocarcinoma and 2 hyperplasias) and 3 cases of tertiary hyperparathyroidism secondary to chronic renal failure.

RESULTS

Uptake of 99mTc-MIBI in the early phase of scintigraphy was associated with larger parathyroid lesions (1.61 +/- 1.61 ml versus 0.33 +/- 0.27 ml; p < 0.02) and higher serum calcium levels (3.00 +/- 0.41 mM versus 2.67 +/- 0.14 mM; p < 0.02). More importantly, we found that a parathyroid oxyphil cell content greater than 25% was more often associated with a positive uptake of 99mTc-MIBI in the late phase of the test (positive late uptake in 78% of lesions with a high oxyphil cell content versus 33% in lesions with an oxyphil cell content between 1% and 25% and 0% in lesions with no oxyphil cells; p < 0.04).

CONCLUSION

These findings suggest that the late retention of 99mTc-MIBI in double-phase scintigraphy is related to parathyroid oxyphil cell content.

Reduction of capillary permeability in the fructose-induced hypertensive rat

Impaired insulin transcapillary transport and the subsequent decrease in insulin delivery to target organs have been suggested to play a role in insulin resistance. These defects were studied in fructose-fed rats, an animal model with insulin resistance. For this study, male Sprague-Dawley rats were fed with either a 60% fructose enriched (F) or a standard chow diet (N) for a total of 2, 4, or 8 weeks. Capillary permeability to albumin was assessed at the end of each dietary period by quantifying the extravasation of albumin-bound Evans blue (EB) dye in different organs. Unanesthetized animals were injected with Evans blue dye (20 mg/kg) in the caudal vein 10 min before being killed and EB dye was extracted by formamide from selected organs collected after exsanguination. As expected, rats had an increase in blood pressure upon feeding with fructose at 4 and 8 weeks (F, 149 +/- 3 mm Hg; N, 139 +/- 3 mm Hg; P < .05). Using this technique, we showed a 56% and a 51% reduction in capillary permeability in skeletal muscles at 4 and 8 weeks of fructose feeding, respectively (4 weeks: N, 44.5 +/- 5.0 microg/g of dry tissue; F, 19.8 +/- 4.2 microg/g of dry tissue; P < .01 and 8 weeks: N, 23.3 +/- 3.7 microg/g of dry tissue; F, 11.3 +/- 4.0 microg/g of dry tissue; P < .05). Similar changes were observed at 4 weeks in the thoracic aorta (N, 82.8 +/- 8.8 microg/g of dry tissue; F, 53.0 +/- 5.1 microg/g of dry tissue; P < .02) and skin (N, 36.0 +/- 5.3 microg of dry tissue; F, 15.0 +/- 2.3 microg/g of dry tissue; P < .02) and at 8 weeks in the liver (N, 107.5 +/- 4.3 microg/g of dry tissue; F, 80.9 +/- 3.2 microg/g of dry tissue; P < .01). In conclusion, fructose feeding is accompanied by a significant and selective reduction of Evans blue leakage primarily in skeletal muscle and liver, and transiently in the skin and aorta, consistent with a role for decreased tissue insulin delivery in insulin resistance.

Evidence that insulin can directly inhibit hepatic glucose production

In order to evaluate the role of portal insulin in the modulation of hepatic glucose production (HGP), measurements of plasma glucose and insulin concentrations and both HGP and peripheral glucose disappearance rates were made following an infusion of a dose of tolbutamide (0.74 mg x m(-2) x min[-1]) in healthy volunteers that does not result in an increase in peripheral vein insulin concentrations or metabolic clearance rate of glucose. The results showed that the infusion of such a dose of tolbutamide was associated with a significant and rapid decline in both HGP (from 9.0 +/- 0.5 to 7.7 +/- 0.5 micromol x kg(-1) x min(-1) or delta = -13.8 +/- 4.5%; p < 0.001 compared to saline) and plasma glucose concentration (from 5.1 +/- 0.2 to 4.4 +/- 0.1 mmol/l or delta = -13.0 +/- 2.1%; p < 0.01 compared to saline). Since neither HGP nor fasting glucose fell when tolbutamide-stimulated insulin secretion was inhibited by the concurrent administration of somatostatin, it indicated that tolbutamide by itself, does not directly inhibit HGP. Finally, HGP fell by 26.3 +/- 6.0% at 10 min after a dose of tolbutamide that elevated both peripheral and portal insulin concentrations, at a time when HGP had barely increased (delta = +6.9 +/- 5.3%). The difference in the magnitude of the two responses was statistically significant (p < 0.03), providing further support for the view that insulin can directly inhibit HGP, independent of any change in flow of substrates from periphery to liver.

Relationship between insulin-mediated glucose disposal and regulation of plasma and adipose tissue lipoprotein lipase

The relationship between insulin-mediated glucose disposal and fasting insulin and triglyceride (TG) concentrations, plasma post-heparin lipoprotein lipase (PH-LPL) activity and mass, and adipose tissue LPL activity, mass, and mRNA content was defined in 19 non-diabetic men. Insulin-mediated glucose uptake [as assessed by determining the steady-state plasma glucose (SSPG) concentration during a continuous infusion of somatostatin, insulin, and glucose] was significantly correlated with fasting TG concentration (r = 0.54, p < 0.02), plasma PH-LPL activity (r = -0.52, p < 0.03) and mass (r = -0.49, p < 0.03), and adipose tissue LPL mRNA content (r = -0.68, p < 0.001). Comparable relationships were also seen when fasting insulin concentration was substituted for SSPG. Although adipose tissue LPL and mass correlated with each other (r = 0.76, p < 0.001) in a fasting state, they were not related to any other variable measured. Using in vivo and molecular biology techniques, these data demonstrate that the more insulin resistant an individual, the lower the level of plasma PH-LPL activity and mass, and the higher the plasma TG concentration. Since lower concentrations of adipose tissue mRNA were also directly correlated with plasma PH-LPL mass (r = 0.57, p < 0.01), and inversely with plasma TG concentration (r = -0.68, p < 0.001) as well as SSPG (r = -0.68, p < 0.001), it can be postulated that the relationship between insulin resistance and LPL activity and plasma TG concentration is associated with the inability of insulin to stimulate the transcription or to increase the intracellular mRNA stability of adipose tissue LPL in insulin resistant individuals.

Glucose turnover and gluconeogenesis during pregnancy in women with and without insulin-dependent diabetes mellitus

OBJECTIVE

To characterize the effect of pregnancy on glucose turnover and gluconeogenesis in healthy women and in women with well-controlled insulin-dependent diabetes mellitus (IDDM).

DESIGN

Prospective clinical study.

SETTING

Clinical research unit of the Hôtel-Dieu de Montréal hospital.

PARTICIPANTS

Five healthy pregnant women and 6 pregnant women with IDDM.

INTERVENTIONS

Glucose turnover and gluconeogenesis in the postabsorptive state at 16 and 32 weeks' gestation and at 24 weeks postpartum were studied with the use of a double stable isotope technique (D[2,3,4,6,6(2)H]-glucose and L[1,2,3(13)C]-alanine). In the women with IDDM, plasma glucose levels were controlled by continuous subcutaneous insulin infusion throughout pregnancy and with a Biostator on the morning of the study.

RESULTS

In the women without IDDM, hepatic glucose production was 11.6 (standard error of the mean [SEM] 2.2) mumol/kg per minute at 16 weeks' gestation, 12.5 (SEM 1.8) mumol/kg per minute at 32 weeks' gestation, and 13.2 (SEM 1.9) mumol/kg per minute at 24 weeks postpartum. In the women with IDDM, it was 10.7 (SEM 2.4) mumol/kg per minute, 10.5 (SEM 1.2) mumol/kg per minute and 12.3 (SEM 0.5) mumol/kg per minute at the same respective periods. The difference in levels between the 2 groups was not significant. Levels of the gluconeogenic precursors alanine and lactate were increased during pregnancy in both the women without IDDM (from 0.18 [SEM 0.02] mmol/L and 0.64 [SEM 0.09] mmol/L, respectively, to 0.25 [SEM 0.02] mmol/L and 1.15 [SEM 0.17] mmol/L, respectively, p < 0.01) and in those with IDDM (from 0.15 [SEM 0.01] mmol/L and 0.47 [SEM 0.04] mmol/L, respectively, to 0.19 [SEM 0.02] mmol/L and 0.70 [SEM 0.01] mmol/L, respectively, p < 0.05). After an overnight fast, gluconeogenesis from alanine was not affected by pregnancy in both groups of women. In the women without IDDM, the plasma insulin level was low in early pregnancy (33.6 [SEM 3.6] pmol/L) and increased in late gestation (87.6 [SEM 9.6] pmol/L) compared with postpartum levels (60.0 [SEM 7.8] pmol/L). Plasma glucagon levels tended to rise in late gestation (from 95.1 [SEM 6.7] ng/L to 116.0 [SEM 36.0] ng/L). In the women with IDDM, the free plasma insulin and plasma glucagon levels were higher in early pregnancy (55.2 [SEM 6.6] pmol/L and 196.1 [SEM 29.8] ng/L, respectively) and did not change significantly during pregnancy.

CONCLUSION

Basal glucose turnover and gluconeogenesis are not increased during pregnancy in women without IDDM or in women with well-controlled IDDM. The decrease in the plasma glucose level during pregnancy suggests that the use of glucose by the growing fetus is augmented and that this is not totally compensated for by a rise in postabsorptive hepatic glucose production. The glucose requirement by the growing fetus is probably supplied by the increased postprandial plasma glucose level.

Fluoxetine improves insulin sensitivity in obese patients with non-insulin-dependent diabetes mellitus independently of weight loss

OBJECTIVE

To study the effect of fluoxetine, a specific serotonin reuptake inhibitor, on insulin sensitivity in obese patients with non-insulin-dependent diabetes mellitus (NIDDM) independently of its action on body weight.

RESEARCH DESIGN AND METHODS

In a randomized, double-blind, placebo-controlled trial, insulin-mediated glucose disposal was measured in 12 obese patients with NIDDM on diet alone before and after four weeks of treatment with either placebo (n = 6) or fluoxetine (n = 6) at a dose level of 60 mg once a day. Insulin-mediated glucose disposal was assessed by the 2-step euglycemic hyperinsulinemic clamp technique. Patients were instructed on a weight-maintaining diet.

RESULTS

Insulin infusion at 40 mU.m-2.min-1 resulted in insulin levels of 720 +/- 70 pmol. L-1 with a mean plasma glucose value of 6.4 +/- 0.2 mmol. L-1. Compared to placebo, fluoxetine increased glucose disposal (M) by 2.4-fold (P < 0.05), the insulin sensitivity index (M/I) by 2.7-fold (P < 0.03) and the glucose metabolic clearance rate (MCR) by 2.9-fold (P < 0.03). Insulin infusion at 400 mU.m-2. min-1 elicited insulin levels of 12947 +/- 1512 pmol. L-1 with a mean plasma glucose value of 5.6 +/- 0.4 mmol. L-1. Compared to placebo, fluoxetine increased M by 30% (P = NS), M/I by 40% (P < 0.04) and MCR by 23% (P < 0.04). Patient weight remained stable throughout the study with no change in dietary intake.

CONCLUSION

Fluoxetine improves insulin-mediated glucose disposal in obese patients with NIDDM independently of weight loss.

Generation of antibodies against a human lipoprotein lipase fusion protein

Antibodies generated against specific proteins are useful tools for studying the physiology and cell biology of the protein of interest. Although antibodies have been successfully generated against lipoprotein lipase (LPL) and used to elucidate many aspects of its biology, there have been problems with the specificity, affinity and availability of these antibodies. To circumvent these problems, we have expressed a portion of human LPL as a bacterial fusion protein. The human LPL bacterial fusion protein was utilized to generate polyclonal antibodies in rabbits that recognize intact human, rat and bovine LPL. Using these antibodies, it was possible to demonstrate a direct correlation between LPL mass and LPL activity from different samples of human post-heparin plasma. In addition, these antibodies were used to develop an ELISA for the measurement of LPL in tissue or plasma. This is a useful means for obtaining polyclonal antibodies to LPL in sufficient quantity and without contaminating mammalian proteins.

Comparison of the hemodynamic and metabolic effects of low-dose hydrochlorothiazide and lisinopril treatment in obese patients with high blood pressure

Patients with high blood pressure tend to be insulin resistant, glucose intolerant, hyperinsulinemic, and dyslipidemic. Since these metabolic defects are accentuated by obesity, we thought it important to compare the effects of 3 months' treatment with either lisinopril (20 mg/day) or low dose hydrochlorothiazide (12.5 mg/day) on blood pressure and glucose, insulin, and lipoprotein metabolism in obese patients with hypertension. There were 14 patients in each group, and they were similar (mean +/- SE) in age (54 +/- 3 v 50 +/- 4 years), gender (nine men/five women), and body mass index (33.4 +/- 0.8 v 33.9 +/- 0.9 kg/m2). Patients treated with lisinopril had a somewhat greater fall in both systolic (18 +/- 3 v 10 +/- 3 mm Hg) and diastolic (12 +/- 2 v 8 +/- 1 mm Hg) blood pressure, but only the change in systolic pressure was statistically significant (P < .05). Plasma glucose, insulin, and triglyceride concentrations were measured at hourly intervals from 8 AM to 4 PM (breakfast at 8 AM and lunch at 12 PM), and there was a modest increase in all three variables following hydrochlorothiazide treatment (P < .05 to P < .09). However, daylong plasma glucose, insulin, and triglyceride concentration did not change with lisinopril treatment. Finally, neither the ability of insulin to mediate glucose disposal nor fasting lipid and lipoprotein concentrations, changed with either treatment. In conclusion blood pressure decreased significantly following treatment with either lisinopril (20 mg/day) or hydrochlorothiazide (12.5 mg/day).(ABSTRACT TRUNCATED AT 250 WORDS)

Additive effects of obesity, hypertension, and type 2 diabetes on insulin resistance

Resistance to insulin-mediated glucose disposal has been previously shown to be increased in association with obesity, high blood pressure, and non-insulin-dependent diabetes mellitus. We initiated the present study to quantify the separate effects of hypertension and non-insulin-dependent diabetes mellitus on insulin resistance in both nonobese and obese subjects. To accomplish this, 88 subjects were divided into the following five experimental groups: normal blood pressure, nonobese (n = 17); normal blood pressure, obese (n = 18); high blood pressure, nonobese (n = 18); high blood pressure, obese (n = 19); and high blood pressure, obese, non-insulin-dependent diabetes mellitus (n = 16). Plasma glucose and insulin concentrations were measured before and after a 75-g oral glucose load. Resistance to insulin-mediated glucose disposal was estimated by determining the steady-state plasma insulin and glucose concentrations during the last 30 minutes of a continuous infusion of somatostatin (5 micrograms/min), exogenous insulin (25 mU/m2 per minute), and glucose (240 mg/m2 per minute). Since the steady-state plasma insulin concentrations are similar in all subjects, the higher the steady-state plasma glucose, the more insulin resistant the individual. Nonobese subjects with normal blood pressure had the lowest plasma glucose and insulin responses and steady-state plasma glucose concentrations, and their values were significantly different from the other four groups. Obese or nonobese subjects with high blood pressure had significantly higher plasma glucose responses and steady-state plasma glucose concentrations than did their respective weight-matched control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in glucose, insulin, lipid, lipoprotein, and apoprotein concentrations and insulin action in doxazosin-treated patients with hypertension. Comparison between nondiabetic individuals and patients with non-insulin-dependent diabetes mellitus

Thirty patients with hypertension were enrolled in this study, 13 had non-insulin-dependent diabetes mellitus (NIDDM) and 17 were nondiabetic. Patients were treated with doxazosin for approximately 4 months, and blood pressure fell significantly (P < .001) in both nondiabetics (149/96 to 134/85 mm Hg) and in those with NIDDM (154/96 to 143/84 mm Hg). In the nondiabetic group, doxazosin treatment was associated with significant improvement in insulin-mediated glucose disposal (P < .05) and lower plasma insulin (P < .001), and triglyceride (P < .001) concentrations measured at hourly intervals from 8 AM to 4 PM (breakfast at 8 AM and lunch at noon). In addition, fasting total plasma (P < .001) and VLDL cholesterol (P < .01), and total plasma (P < .05), VLDL (P < .08), LDL (P < .01), HDL (P < .01) triglyceride concentrations were lower following doxazosin treatments in the nondiabetic group, as was the ratio of total to HDL cholesterol (P < .001). Finally, apoprotein B concentrations fell with doxazosin in the nondiabetic group (P < .01). Significant changes seen in the group with NIDDM included a decrease in the ratio of total to HDL cholesterol (P < .001) and a fall in apoprotein B concentration (P < .05). However, values for all other variables did not change significantly with treatment in this group. Thus, doxazosin treatment of nondiabetic subjects with high blood pressure was associated with a series of changes in glucose, insulin, and lipoprotein metabolism that should decrease risk of coronary heart disease (CHD) in these individuals.(ABSTRACT TRUNCATED AT 250 WORDS)