Plasma Levels Of Fasting Insulin Research Articles

Features of glucose metabolism in acromegaly depending on the type of treatment

Aim of the study was to investigate the features of glucose metabolism in patients with acromegaly depending on treatment. Materials and methods: 63 patients with acromegaly: 29 patients with newly diagnosed acromegaly, 25 patients receiving somatostatin analogs (SSA) therapy and 9 patients underwent surgical treatment. Patients with earlier revealed diabetes mellitus (DM) were not included. The characterization of glucose metabolism was carried out by means of an assessment of fasting insulin plasma levels (FIP) and indexes of an insulinresistance (IR) HOMA-R and an insulinsensivity (IS) MATSUDA. Results: In patients receiving SSA therapy the carbohydrate metabolism disorders (CMD) were revealed in 92%, among newly diagnosed acromegalic patients – in 62% and in patients after surgical treatment in 33% of cases. In newly diagnosed acromegalic patients index MATSUDA was 3,5 times lower than in patients receiving SSA therapy, and 4 times lower than in patients after surgical treatment ((р=0,001). НОМА-R in newly diagnosed acromegalic patients was 3,7 times higher than in other groups, p=0,003 and the level of FIP was 4,3 times higher than in patients receiving SSA therapy and 2,9 times higher than in patients after surgical treatment (р=0,001). The index MATSUDA in newly diagnosed acromegalic patients with early CMD was 2,9 times lower, р=0,006, НОМА-R – 2,5 times higher, р=0,025 and FIP 2,4 times higher, р=0,039 than in patients with early CMDs without acromegaly. Conclusions: In patients with newly diagnosed acromegaly in the absence of CMDs increase in IR is compensated by hyperinsulinemia. In patients, receiving SSA therapy the IR decreases, however suppression of secretion of insulin leads to increase in percentage of DM in this group. After surgical treatment IR decreases against higher level of fasting plasma insulin that leads to normalization of carbohydrate metabolism. Keywords: Acromegaly, secondary diabetes mellitus, insulinresistance, MATSUDA, HOMA-R.

Differential insulin response to myo-inositol administration in obese polycystic ovary syndrome patients

Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, chronic anovulation, polycystic ovaries at ultrasound evaluation, and quite frequently by insulin resistance or compensatory hyperinsulinemia. Attention has been given to the role of inositol-phosphoglycan (IPG) mediators of insulin action and growing evidences suggest that a deficiency of d-chiro-inositol (DCI) containing IPG might be at the basis of insulin resistance, frequent in PCOS patients. On such basis, we investigated the efficacy on insulin sensitivity and hormonal parameters of 8 weeks treatment with myo-inositol (MYO) (Inofert, ItalPharmaco, Milano, Italy) at the dosage of 2 g day in a group (n = 42) of obese PCOS patients,. After the treatment interval body mass index (BMI) and insulin resistance decreased together with luteinizing hormone (LH), LH/FSH and insulin. When subdividing the patients according to their fasting insulin levels, Group A (n = 15) insulin below 12 µU/ml and Group B (n = 27) insulin above 12 µU/ml, MYO treatment induced similar changes in both groups but only patients of Group B showed the significant decrease of both fasting insulin plasma levels (from 20.3 ± 1.8 to 12.9 ± 1.8 µU/ml, p < 0.00001) and of area under the curve (AUC) of insulin under oral glucose tolerance test (OGTT). In conclusion, our study supports the hypothesis that MYO administration is more effective in obese patients with high fasting insulin plasma levels.

Pioglitazone improves the cardiovascular profile in patients with uncomplicated systemic lupus erythematosus: a double-blind randomized clinical trial

We studied the effect of pioglitazone on insulin levels, inflammation markers, high-density lipoprotein (HDL) composition and subclasses distribution, in young women with uncomplicated systemic lupus erythematosus (SLE). This double-blind trial included 30 premenopausal women (30 ±8 years old) with SLE, who were randomized to pioglitazone (30 mg/day) or placebo treatment for 3 months. Plasma and HDL lipids were determined by colorimetric enzymatic assays, insulin by radioimmunometric assay, inflammation by immunonephelometry and HDL size and subclasses distribution by a native 4-30% polyacrylamide gradient gel electrophoresis. Compared with placebo, pioglitazone significantly increased HDL-cholesterol plasma levels (14.2%), reduced fasting insulin plasma levels (23.6%) and the homeostasis model assessment-insulin resistance (31.7%). C-reactive protein (70.9%) and serum amyloid A (34.9%) were also significantly reduced with the pioglitazone use, whereas the HDL particle size was increased (8.80 nm vs. 8.95 nm; p = 0.044) by changes in the distribution of HDL(2b), HDL(3b), and HDL(3c) subclasses. The change in HDL size correlated with a rise in free and cholesterol-ester content in the HDL particles. Pioglitazone significantly enhanced insulin sensitivity, reduced inflammation, and modified HDL characteristics, suggesting a potential beneficial effect of this drug in patients with SLE with a risk to develop cardiovascular disease. This trial is registered at ClinicalTrials.gov Protocol Registration System, with the number NCT01322308.

Insulin Sensitivity, Serum Lipids, and Systemic Inflammatory Markers in School-Aged Obese and Nonobese Children

The impact of obesity as a systemic low-grade inflammatory process has only partially been explored. To this effect, 704 community-based school-aged children (354 obese children and 350 age-, gender-, and ethnicity-matched controls) were recruited and underwent assessment of plasma levels of fasting insulin and glucose, lipids, and a variety of proinflammatory mediators that are associated with cardiometabolic dysfunction. Obese children were at higher risk for abnormal HOMA and cholesterol levels. Furthermore, BMI z score, HOMA, and LDL/HDL ratio strongly correlated with levels of certain inflammatory mediators. Taken together, obesity in children is not only associated with insulin resistance and hyperlipidemia, but is accompanied by increased, yet variable, expression of markers of systemic inflammation. Future community-based intervention and phenotype correlational studies on childhood obesity will require inclusion of expanded panels of inflammatory biomarkers to provide a comprehensive assessment of risk on specific obesity-related morbidities.

Effects of restrained eating behaviour on insulin sensitivity in normal-weight individuals

Restrained eating behaviour has been linked to abnormalities in metabolic and endocrine functions. However, the impact of restraint on fasting insulin and glucose plasma levels and insulin sensitivity remains controversial. Moreover, the few postprandial studies to date are limited by an inappropriate sampling time frame and a low “net” energy and carbohydrate load. The aims of this study are to assess the role of dietary restraint on fasting and postprandial plasma levels of insulin, glucose, triacylglycerol (TAG) and non esterified fatty acids (NEFA) in healthy volunteers with a normal and stable body weight and to determine whether the effect of restraint on the plasma levels of the previous hormones/metabolites is load dependent. Normal-weight participants (21 women and 12 men) were classified as restrained/unrestrained based on the restraint scale of the Three Factor Eating Questionnaire-18R and Dutch Eating Behaviour Questionnaire. The impact of restraint on the plasma levels of different hormones/metabolites was measured, in response to a 500 kcal and 1000 kcal breakfast, using a randomised crossover design. Restraint was associated with lower fasting insulin plasma levels ( P < 0.05) and a lower insulin ( P < 0.015) and glucose ( P < 0.05) plasma levels in the postprandial state, but did not impact on TAG or NEFA. Moreover, restrained eaters showed a better fasting ( P < 0.05) and postprandial insulin sensitivity ( P < 0.01). Restrained eating behaviour has, therefore, a significant impact on both fasting and postprandial glucose metabolism, being associated with increased insulin sensitivity. These findings suggest the need for adjusting for restraint level in studies where glucose metabolism is a major outcome.

Associations between insulin resistance and TNF-α in plasma, skeletal muscle and adipose tissue in humans with and without type 2 diabetes

Clear evidence exists that TNF-alpha inhibits insulin signalling and thereby glucose uptake in myocytes and adipocytes. However, conflicting results exist with regard to the role of TNF-alpha in type 2 diabetes. We obtained blood and biopsy samples from skeletal muscle and subcutaneous adipose tissue in patients with type 2 diabetes (n = 96) and healthy controls matched for age, sex and BMI (n = 103). Patients with type 2 diabetes had higher plasma levels of fasting insulin (p < 0.0001) and glucose (p < 0.0001) compared with controls, but there was no difference between groups with regard to fat mass. Plasma levels of TNF-alpha (p = 0.0009) and soluble TNF receptor 2 (sTNFR2; p = 0.002) were elevated in diabetic patients. Insulin sensitivity was correlated with quartiles of plasma TNF-alpha after adjustment for age, sex, obesity, WHR, neutrophils, IL-6 and maximum O(2) uptake (VO2/kg) in the diabetes group (p < 0.05). The TNF mRNA content of adipose or muscle tissue did not differ between the groups, whereas muscle TNF-alpha protein content, evaluated by western blotting, was higher in type 2 diabetic patients. Immunohistochemistry revealed more TNF-alpha protein in type 2 than in type 1 muscle fibres. After adjustment for multiple confounders, plasma TNF-alpha is associated with insulin resistance. This supports the idea that TNF-alpha plays a significant role in the pathogenesis of chronic insulin resistance in humans. However, findings on the TNF-alpha protein levels in plasma and skeletal muscle indicate that measurement of TNF mRNA content in adipose or muscle tissue provides no information with regard to the degree of insulin resistance.

Insulin Resistance Is Associated With Hypercortisolemia in Polynesian Patients Treated With Antipsychotic Medication

Type 2 diabetes is more prevalent in the indigenous Polynesian population of New Zealand (Maori) than in Europeans. The aim of this study was to determine whether insulin resistance in Maori psychiatric patients was associated with antipsychotic treatment and to investigate the mechanism of an association. Thirty adult Maori psychiatric patients receiving antipsychotic medication for >6 months and 30 healthy, age-, sex-, and BMI-matched control subjects were enrolled. Early morning fasting blood samples were analyzed for plasma levels of glucose, insulin, A1C, triglycerides, total cholesterol, IGF-1, cortisol, cortisol-binding globulin (CBG), and adiponectin. The patient group had significantly higher median fasting insulin plasma levels than the control group (P = 0.002), which were independent of BMI, age, and sex. In addition, the patient group had significantly higher total cortisol (P = 0.03) and lower CBG levels (P = 0.004) than the control group, resulting in significantly higher levels of free cortisol (P = 0.004). The patient group was also significantly more hypoglycemic (P = 0.026) and hypertriglyceridemic (P = 0.028) than the control group. There was no significant difference in BMI, waist circumference, A1C, total cholesterol, IGF-1, or adiponectin levels between the two groups. An increase in insulin resistance is seen in Maori psychiatric patients treated with antipsychotic medication. Therefore, Polynesian ethnicity should be considered in prescribing practice and general care of this group. In addition, the hypothalamic-pituitary-adrenal axis may have an important role in the mechanism by which this insulin resistance develops.

Relation of fasting insulin plasma levels to restenosis after elective coronary stent implantation in patients without diabetes mellitus

The results of this study in 172 patients without diabetes who underwent elective stent implantation showed a significant correlation between preprocedural fasting insulin serum levels and angiographic late lumen loss (correlation coefficient 0.49, p <0.0001). Furthermore, the waist-to-hip ratio and C-peptide and hemoglobin A1c serum levels were associated with the occurrence of binary angiographic restenosis.

Relationship between Homocysteine and Insulin Resistance in Women with Polycystic Ovary Syndrome

Hyperhomocysteinemia is a risk factor for atherosclerotic vascular diseases. It is known that plasma homocysteine levels are higher in polycystic ovary syndrome (PCOS) patients than in healthy subjects. The aim of our study was to determine the relationship between plasma homocysteine level and insulin resistance in women with PCOS. Twenty-nine patients (age, 23.90 +/- 5.86 years) and twenty-five healthy subjects (age, 25.24 +/- 4.28 years) were involved in the study. Plasma levels of fasting insulin, glucose, homocysteine, FSH, and LH levels were measured. A statistically significant difference in plasma concentrations of HOMA index, homocysteine, basal insulin levels and LH/FSH ratios was observed between groups (P = 0.001, P = 0.001, P = 0.001, and P = 0.01, respectively). There was no relationship between Hcy and the other variables. In multiple logistic regression analysis, age, BMI and insulin resistance were not predictors of Hcy.

High insulin levels and increased low-density lipoprotein oxidizability in pediatric patients with systemic lupus erythematosus.

To examine low-density lipoprotein (LDL) size, LDL susceptibility to oxidation, and plasma insulin levels in children with systemic lupus erythematosus (SLE). Fifty-nine SLE patients and 59 healthy, age-matched control subjects were studied. LDL size was determined by gradient gel electrophoresis. LDL oxidizability was assessed by lag time for conjugated diene formation during copper incubation. Plasma levels of fasting insulin, glucose, lipids, lipoproteins, apolipoproteins B and A-I, and fatty acids were also measured. Compared with control subjects, SLE patients showed significantly higher plasma insulin levels and increased susceptibility of LDLs to oxidation. Patients with active disease were more likely than patients with inactive disease or control subjects to have the following lipid characteristics: small, dense LDL subclass, elevated total cholesterol levels, elevated LDL cholesterol levels, elevated triglyceride levels, and low levels of high-density lipoprotein cholesterol (HDL-C). Statistically significant direct correlations were observed between disease activity and triglyceride levels and between disease activity and lag time, whereas significant inverse correlations were found between disease activity and HDL-C levels and between disease activity and LDL size. Prednisone dosage explained only 15.6% of the variance in insulin levels. SLE patients have higher plasma insulin levels and increased LDL oxidizability compared with healthy control subjects. These abnormalities may contribute to the accelerated atherosclerosis observed in patients with SLE.

Persistent short stature, other potential outcomes, and the effect of growth hormone treatment in children who are born small for gestational age.

Persistent short stature, other potential outcomes, and the effect of growth hormone treatment in children who are born small for gestational age.

Absence of clinically overt atherosclerotic vascular disease and adverse changes in cardiovascular risk factors in 70 patients with insulinoma.

Hyperinsulinemia has been assumed to contribute to the pathogenesis of atherosclerosis. To assess the reliability of such claim we planned a retrospective study on a cohort of patients with pancreatic insulin producing neoplasm. A correlation was sought between fasting insulin plasma levels and the metabolic profile emerging from those parameters known to be cardiovascular risk factors, i.e. plasma triglycerides and cholesterol, insulin resistance, hypertension. Special attention was paid to the duration of disease, because the time exposure to hyperinsulinemia could play an important role in developing cardiovascular disease. Seventy patients, 41 females and 29 males, aged 44.9 +/- 1.96 yr (range 15-80), with surgically proved insulinoma were included in the study. Chronic exposure to hyperinsulinemia was documented through the measurement of insulin plasma levels either in the fasting state or post-prandially, resulting in 44.7 +/- 3.28 and 149.9 +/- 12.22 microU/ml, respectively. Fasting glycemia in average was 45.3 +/- 1.34 mg/dl. Plasma triglycerides and cholesterol concentrations were 136.3 +/- 7.93 and 195.8 +/- 5.18 mg/dl, respectively, their distribution overlapping that anticipated for the general population. No correlation arose between the degree of hyperinsulinemia and the lipidic profile. Preoperative blood pressure was 136.9 +/- 2.87 mmHg, systolic and 81.9 +/- 1.32 mmHg, diastolic. Hypertension was present in 5 (7.1%) out of 70 patients and persisted after tumor removal. A condition of insulin resistance (M = 4.06 +/- 0.4 mg/kg min vs 7.41 +/- 0.21) was documented through the euglycemic hyperinsulinemic clamp technique in 20 patients and showed a positive and significant correlation with fasting insulinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminoacid polymorphisms of insulin receptor substrate-1 in non-insulin-dependent diabetes mellitus

Since relative or absolute insulin deficiency and insulin insensitivity are involved in the aetiology of non-insulin-dependent diabetes mellitus (NIDDM), we examined whether patients with NIDDM exhibit genetic variability in the coding region of insulin receptor substrate-1 (IRS-1), a candidate gene that is ubiquitous in insulin-sensitive and insulin-like growth factor 1 (IGF1) sensitive tissues, including those that determine glucose production and clearance and those with regulatory effects on pancreatic β-cell function. IRS-1 has a central role as an adaptor molecule that links the insulin- receptor and IGF1-receptor kinases with enzymes that regulate cellular metabolism and growth. Single-stranded conformation polymorphism analysis and direct nucleotide sequencing were applied to genomic DNA from 86 unrelated patients with NIDDM and 76 normoglycaemic controls. 10 of the patients with NIDDM and 3 of the controls were heterozygous at codon 972 for a polymorphism in which glycine was substituted with arginine. Moreover, at codon 513, 6 patients with NIDDM and 2 controls had a heterozygous polymorphism with a transition from alanine to proline. None of the polymorphism carriers had both aminoacid variants and the total allelic frequency of IRS-1 polymorphisms was about three times higher in patients with NIDDM than in controls (p=0·02). Both aminoacid substitutions were located close to tyrosine phosphorylation motifs that are putative recognition sites for insulin and IGF1 signal transmission proteins. Analysis of the phenotypes showed that patients with NIDDM who had IRS-1 variants did not differ in their degree of insulin resistance compared with patients without known IRS-1 polymorphisms. However, carriers of the codon 972 variant had significantly lower plasma levels of fasting insulin and C-peptide. Our results suggest that aminoacid polymorphisms in IRS-1 may be involved in the aetiology of a subset of late-onset NIDDM.