[Show abstract][Hide abstract] ABSTRACT: Vitamin D deficiency may increase the risk of type 2 diabetes. We therefore investigated whether serum concentrations of 25-hydroxyvitamin D [25(OH)D] would predict the development of prediabetes (impaired fasting glucose, impaired glucose tolerance or the two combined) and type 2 diabetes, either on their own or when combined with serum concentrations of IGF-1 or IGF-binding protein-1 (IGFBP-1), which may interact with 25(OH)D.
At baseline, participants aged 35-56 years without known type 2 diabetes were examined using OGTTs, 25(OH)D and IGF peptide measurements, and anthropometric and lifestyle data. Participants who had prediabetes or type 2 diabetes at follow-up 8-10 years later were selected as cases; these were then age- and sex-matched to controls with normal glucose tolerance (NGT) at both baseline and follow-up, giving a total of 980 women and 1,398 men.
Men but not women in the highest quartile of 25(OH)D level had a decreased OR for developing type 2 diabetes after adjustment for confounders (OR 0.52, 95% CI 0.30, 0.90), an effect accounted for by individuals with prediabetes, but not with NGT, at baseline. In both sexes, progression from prediabetes to type 2 diabetes was reduced by about 25% per 10 nmol/l increase in 25(OH)D. A high IGFBP-1 value was a better predictor of a reduced risk of type 2 diabetes than high 25(OH)D for both sexes, whereas high IGF-1 concentrations predicted a decreased risk only in men.
High serum 25(OH)D concentrations predict a reduced risk of type 2 diabetes in individuals with prediabetes, but not NGT. There were no significant interactions between 25(OH)D and IGFBP-1 or IGF-1 in terms of risk of diabetes. Our data suggest that vitamin D supplementation should be evaluated for the prevention of type 2 diabetes in prediabetic individuals.
[Show abstract][Hide abstract] ABSTRACT: Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are major incretins with important effects on glucoregulatory functions. The aim of this study was to investigate effects of GIP and GLP-1 on gastric emptying and appetite after a mixed meal, and effects on insulin secretion and glucose disposal in humans.
Randomized crossover single-blind study in 17 healthy volunteers receiving GIP (2 or 5 pmol kg(-1) min(-1), n = 8), GLP-1 (0.75 pmol kg(-1) min(-1), n = 9) or NaCl for 180 min with a radionuclide-labeled omelette and fruit punch (370 kcal). Outcome measures were gastric emptying rate, insulinogenic index, hunger, satiety, desire to eat, and prospective food consumption. Blood was analyzed for GIP, GLP-1, glucagon, C-peptide, peptide YY (PYY) and ghrelin.
Glucose-dependent insulinotropic polypeptide 2 and 5 pmol kg(-1) min(-1) decreased gastric half-emptying time from 128.5 ± 34.0 min in controls to 93.3 ± 6.3 and 85.2 ± 11.0 min (P < 0.05). Glucose-dependent insulinotropic polypeptide 5 pmol kg(-1) min(-1) decreased postprandial glucose (P < 0.001) and insulin (P < 0.05) with increased insulinogenic index. Glucose-dependent insulinotropic polypeptide had no effects on hunger, desire to eat, satiety or prospective consumption. Glucagon-like peptide-1 0.75 pmol kg(-1) min(-1) increased half-emptying time from 76.6 ± 7.6 min to 329.4 ± 71.6 (P < 0.01). Glucagon-like peptide-1 decreased plasma glucose and insulin (both P < 0.05-0.001), and increased insulinogenic index markedly. Hunger, desire to eat and prospective consumption were decreased (P < 0.05), and satiety borderline increased (P < 0.06).
The incretin effect of GIP and GLP-1 differs as GLP-1 exerts a strong glucoregulatory incretin through inhibition of gastric emptying, which GIP does not. Thus, GLP-1 as incretin mimetic may offer unique benefits in terms of weight loss in treatment of type 2 diabetes.
Full-text · Article · Nov 2010 · Neurogastroenterology and Motility
[Show abstract][Hide abstract] ABSTRACT: The efficiency of six different methods available for topographical diagnosis of primary al-dosteronism was analysed in retrospect from 11 surgically verified cases and by an analysis of 360 cases reported in the literature. Differentiation between hyperplasia and adenoma was most safely predicted by monitoring the diurnal rhythm of plasma aldo-sterone and its reaction to posture. Adrenal vein catheterization with aldosterone determinations was helpful in establishing the presence of hyperplasia in approximately 70 % of these cases. Correct localization of aldosterone-producing adenomas was made in more than 90% by vein catheterization while veno-graphy and radio-cholesterol scintigraphy had lower diagnostic accuracy. It is therefore suggested that determination of plasma aldosterone both by vein catheterization and by peripheral monitoring should be used ahead of other diagnostic procedures for topographical examinations in primary aldoste-ronism.
No preview · Article · Apr 2009 · Journal of Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: The regulation of lipolysis has been studied in subcutaneous adipose tissue removed under local anesthesia from hypothyroid patients. As control subjects were used hypothyroid subjects on replacement therapy. Noradrenaline induced no significant increase in lipolysis in tissue removed from hypothyroid patients, while the increase in glycerol release from adipose tissue of the control group was almost twofold. The addition of the alpha-adrenergic blocking agent phentholamine to noradrenaline-containing media produced a significant increase in the glycerol release from tissue of the hypothyroid patients as well as from the control subjects. Iso-propylnoradrenaline, a nearly selective beta-adrenergic agonist, theophylline or dibutyryl-cyclic AMP stimulated lipolysis in tissue from both groups. These results indicate that the lipase system cannot be the rate-limiting factor for the lipolytic response to noradrenaline in adipose tissue from hypothyroid patients. The decreased lipolytic response to noradrenaline in this tissue seems to be due to a more pronounced alpha-adrenergic effect of noradrenaline counteracting the lipolytic effect mediated by the beta-adrenergic receptor.
No preview · Article · Apr 2009 · Journal of Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: A dose-response study of the inhibitory effect of epinephrine on glucose-induced insulin secretion in man has been performed. The results demonstrate the exquisite sensitivity of the pancreatic β-cells to epinephrine, as small a dose as 3 mμg/kg/min inducing a 50% inhibition. These studies emphasize the physiological significance of epinephrine for the regulation of insulin secretion. They also show that in previous studies in man and animals supramaximal amounts of epinephrine have been employed. Our results also suggest that the actions of epinephrine and glucose on insulin secretion are competitive. Infusion of aminophylline had only a minor inhibitory effect on the action of epinephrine. Therefore, our data do not permit the conclusion that epinephrine suppresses insulin release exclusively by diminishing the rate of synthesis of cyclic AMP. Other possible mechanisms are discussed.
No preview · Article · Apr 2009 · Journal of Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: TCF7L2, HHEX and IDE on chromosome 10q23-25 reside within the linkage region for type 2 diabetes (T2D). Previous studies including ours have demonstrated that genetic polymorphisms in these three loci are associated with T2D, respectively. But, it is unclear whether TCF7L2, independently or interactively with HHEX and IDE, confer the susceptibility to T2D. In the present study, we first replicated genetic association study of the TCF7L2 gene in a Swedish cohort including 528 non-diabetic healthy controls and 243 T2D patients and then evaluated combining effect from common risk polymorphisms in TCF7L2-HHEX-IDE loci. T2D patients were diagnosed in the intermediate study time. To avoid influence from anti-diabetic treatment, baseline data in all T2D patients were used for analysis. We found that SNPs rs7901695, rs4506565, rs7903146 and rs12255372 in the TCF7L2 gene were strongly associated with T2D (p<0.004). In rs7903146, T2D patients carrying genotypes CT or TT had higher fasting plasma glucose (FPG) levels (p=0.042) and lower HOMA-beta index (p=0.015) and BMI (p=0.015) compared to the patients carrying CC genotype. Furthermore, the risk alleles from TCF7L2 rs7903146 polymorphism either with IDE rs2251101 polymorphism (p=0.0257, OR=1.398) or with HHEX rs1544210 polymorphism (p=0.0024, OR=1.514) were significantly associated with T2D. When risk alleles from three loci were combined, the association with T2D remained significant (p=0.0018, OR=1.506). The present study thus provides evidence that TCF7L2, as the main gene, together with HHEX and IDE loci have combining effects on genetic predisposition to T2D.
No preview · Article · Apr 2009 · Experimental and Clinical Endocrinology & Diabetes
[Show abstract][Hide abstract] ABSTRACT: Incretin hormones often display inhibitory actions on gut motility. The aim of this study was to investigate if altered responsiveness to glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) as regards insulin release and small bowel motility could bring further clarity to the pathophysiology of diabetes in the Goto-Kakizaki (GK) rat. The isolated perfused pancreas was studied in male GK and Wistar rats (controls) under euglycemic and hyperglycemic conditions. Glucose-dependent insulinotropic peptide (10 nmol L(-1)) or GLP-1 (10 nmol L(-1)) were added to the medium and perfusate was collected and analysed for insulin. Moreover, GK and Wistar rats were supplied with bipolar electrodes in the small bowel and myoelectric activity was recorded during intravenous administration of GIP (1-400 pmol kg(-1) min(-1)) or GLP-1 (0.1-20 pmol kg(-1) min(-1)). Finally, tissue was collected from GK and Wistar rats for RNA extraction. Under euglycemia, GIP and GLP-1 stimulated the initial insulin response by 10-fold in GK rats (P < 0.05). At later hyperglycemia, the insulin response to GIP and GLP-1 was blunted to about one-third compared with controls (P < 0.05). In the bowel GLP-1 was about 2.6-16.7 times more potent than GIP in abolishing the migrating myoelectric complex in the GK and control rats. Polymerase chain reaction (PCR) showed GIP and GLP-1 receptor gene expression in pancreatic islets and in small bowel. The initially high, but later low insulin responsiveness to stimulation with GIP and GLP-1 along with inhibition of small bowel motility in the GK rat indicates a preserved incretin response on motility in diabetes type 2.
Full-text · Article · Dec 2008 · Neurogastroenterology and Motility
[Show abstract][Hide abstract] ABSTRACT: Insulin-like growth factor-binding protein-1 (IGFBP-1) production in the liver is inhibited by insulin, and low circulating levels are associated with the metabolic syndrome. The aim of this study was to evaluate the predictive role and change in IGFBP-1 concentrations during development of abnormal glucose regulation.
IGFBP-1 levels were determined at baseline and at 10 years in an incident case-control prospective study of Swedish white men aged 35-56 years. Individuals with normal glucose tolerance at baseline who developed abnormal glucose tolerance during a 10 year period (n = 355) according to WHO criteria were pair-matched to controls for age and family history of diabetes.
Fasting IGFBP-1 concentrations were lower in individuals who later developed abnormal glucose regulation and correlated inversely with fasting proinsulin values (r = -0.48; p < 0.0001), and both were significant predictors. Individuals in the highest quartile at baseline for an algorithm incorporating fasting IGFBP-1, blood glucose, proinsulin and waist and height had a 40-fold increased risk of developing type 2 diabetes compared with the lowest quartile (95% CI 7.7-214). IGFBP-1 increased 32% (95% CI 17-49%) during the 10 years in those developing diabetes and was increased in relation to insulin levels, suggesting the emergence of hepatic insulin resistance. Moreover, elevated IGFBP-1 levels at follow-up were associated with higher 2 h glucose values during an OGTT.
Low IGFBP-1 predicts the development of abnormal glucose regulation and, as an inhibitor of the insulin-like actions of insulin-like growth factors, elevated levels of IGFBP-1 after the development of diabetes may also play a pathophysiological role.
[Show abstract][Hide abstract] ABSTRACT: Glucagon-like peptide-1 (GLP-1) is released after food intake to act as an incretin. GLP-1 also inhibits gastric emptying and increases satiety. In rats, GLP-1 inhibits small bowel motility. Our aim was to study the effects of GLP-1 on gastrointestinal motility in healthy subjects and patients with irritable bowel syndrome (IBS). Antro-duodeno-jejunal manometry was carried out during a 4-h control period with saline, followed by a 4-h period with intravenous GLP-1 (healthy: 0.7 and 1.2 pmol kg(-1) min(-1) (n = 16); IBS, 1.2 and 2.5 pmol kg(-1) min(-1) (n = 14). Plasma was analysed for GLP-1 and gut hormones, and gut tissue expression of GLP-1 receptor was studied. In healthy subjects, GLP-1 0.7 pmol kg(-1) min(-1) reduced the migrating motor complexes (MMCs) from a median of 2 (range 2-3) to 0.5 (0-2), and motility index from 4.9 +/- 0.1 to 4.3 +/- 0.3 ln Sigma(mmHg*s min(-1)) in jejunum, while GLP-1 1.2 pmol kg(-1) min(-1) diminished MMCs from 2 (2-3) to 1.5 (1-2.5), and motility index from 5.2 +/- 0.2 to 4.4 +/- 0.2. In IBS patients, GLP-1 1.2 pmol kg(-1) min(-1) reduced the MMCs from 2.5 (2-3.5) to 1 (0-1.5) without affecting motility index. At 2.5 pmol kg(-1) min(-1) GLP-1 decreased MMCs from 2 (1.5-3) to 1 (0.5-1.5), and motility index from 5.2 +/- 0.2 to 4.0 +/- 0.5. Motility responses to GLP-1 were similar in antrum and duodenum. Presence of the GLP-1 receptor in the gut was verified by reverse transcriptase PCR. In conclusion, the gut peptide GLP-1 decreases motility in the antro-duodeno-jejunal region and inhibits the MMC in healthy subjects and IBS patients.
Full-text · Article · Jul 2008 · Neurogastroenterology and Motility
[Show abstract][Hide abstract] ABSTRACT: The diabetogenic effect of excess growth hormone (GH) such as that in acromegaly is well known. However, the contribution of the various components to hepatic glucose production (HGP) is not completely understood. In this study we evaluated insulin resistance, HGP, gluconeogenesis (GNG), and glycogenolysis (GLY) in five patients with acromegaly before and after pituitary microsurgery. Insulin resistance was estimated by the HOMA index. HGP was measured using a primed continuous (6,6- 2H2) glucose infusion, and GNG was measured from 2 H enrichment at carbons 2 and 5 of blood glucose on ingestion of 2H2O. The ratio of these enrichments equals the fractional contribution of GNG to HGP, and GLY was calculated as the difference between HGP and GNG. All measurements were performed after 12 hours of fasting. Levels of GH and IGF-I decreased, as did the HOMA index (p<0.05). HGP was reduced from 11.4 micromol/kg/min to 9.7 micromol/kg/min (p=0.032). GNG contributed most to HGP. GNG was unchanged, whereas GLY's fraction decreased 29% (p=0.056) postoperatively. This pilot study indicates that GNG is the main contributor to HGP and that GLY is more sensitive than is GNG to the insulin resistance existing in acromegaly.
No preview · Article · Jul 2008 · Hormone and Metabolic Research
[Show abstract][Hide abstract] ABSTRACT: To determine the role of psychological distress as a predictor of pre-diabetes and Type 2 diabetes.
This cohort study comprised 2127 Swedish middle-aged men and 3100 women with baseline normal glucose tolerance measured by oral glucose tolerance test. At follow-up 8-10 years later, 245 men and 177 women had pre-diabetes [impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and IFG + IGT] and Type 2 diabetes was detected in 103 men and 57 women. Baseline psychological distress was measured by an index of five questions concerning anxiety, apathy, depression, fatigue and insomnia. Odds ratios (ORs) were estimated for pre-diabetes and Type 2 diabetes in association with total psychological distress. In addition, ORs of the single-item questions were calculated.
In men, adjusted ORs (95% confidence interval) in the highest index group of psychological distress compared with the lowest group were 1.9 (1.2-2.8) and 2.2 (1.2-4.1) for pre-diabetes and Type 2 diabetes, respectively. Corresponding estimates in women were 1.2 (0.7-2.1) and 0.5 (0.2-1.2). In the middle symptoms groups, adjusted ORs in men were 1.1 (0.8-1.4) for pre-diabetes and 1.2 (0.7-2.0) for Type 2 diabetes and in women 1.8 (1.1-3.0) and 0.7 (0.3-1.4). When analysed separately, the associations with each of the five single factors were similar.
The results indicate that psychological distress, including symptoms of anxiety, apathy, depression, fatigue and insomnia, increases the risk of pre-diabetes and Type 2 diabetes in Swedish middle-aged men. Increased risks were not present in women, except for pre-diabetes in the middle index group.
No preview · Article · Jun 2008 · Diabetic Medicine
[Show abstract][Hide abstract] ABSTRACT: Our previous study using the Goto-Kakizaki rat implicates that the adenylyl cyclase 3 (AC3) is a candidate gene for genetic study of metabolic disorders. The present study aimed to investigate the susceptibility of genetic variation of the AC3 gene in type 2 diabetes (T2D) patients and obese subjects.
Variation screening in the putative promoter and validation of single nucleotide polymorphisms (SNPs) covering the AC3 gene were performed. In total, 630 Swedish men, including 243 T2D patients (BMI from 18.4 to 45.6 kg m(-2)), 199 obese subjects with normal glucose tolerance (NGT, BMI> or =30 kg m(-2)) and 188 control subjects (NGT, BMI< or =26 kg m(-2)), were genotyped.
A novel variant -17A/T in the promoter was identified, but no significant association of this polymorphism with T2D was found. SNPs rs2033655 C/T and rs1968482 A/G were found to be significantly associated with obesity when T2D patients had BMI> or =30 kg m(-2) (P=0.003 and 0.005). The significance was borderline in T2D patients with BMI<30 kg m(-2) (P=0.051 and 0.084) and disappeared in T2D patients with BMI< or =26 kg m(-2). Importantly, analysis in obese subjects with NGT demonstrated that these two polymorphisms were strongly associated with obesity per se (P=0.028 and 0.003). Furthermore, analyses for diplotypes (haplotypic genotypes) predicted an association with BMI in obese subjects.
The present study provides the first evidence that AC3 polymorphisms confer the risk susceptibility to obesity in Swedish men with and without type 2 diabetes.
Full-text · Article · Mar 2008 · International journal of obesity (2005)
[Show abstract][Hide abstract] ABSTRACT: It is generally accepted that a poor glycaemic control increases the risk for development of vascular complications in diabetic patients. This advocates for early introduction of insulin treatment in patients with type 2 diabetes exhibiting a secondary failure to oral treatment. This strategy is facilitated by introduction of long-acting insulin glargine and biphasic insulin aspart 70/30. The introduction of Glucagon-like peptide-1 (GLP-1) mimetics and dipeptidyl peptidase 4 (DPP-4) inhibitors in treatment of type 2 diabetes will however, to a large extent, influence therapeutic policy. Thus we suggest that DPP-4 inhibitors or long-acting GLP-1 mimetics will be used as either first-line therapy or as an early addition to metformin. The already generated results in animal and clinical studies suggest that these two classes of antidiabetic drugs may in addition to improving glycaemic control protect islet beta-cell mass and thereby postpone development of a secondary failure. When patients treated with metformin, sulfonylurea (SU), tiazolidinediones or a combination of these drugs fail, the GLP-1 mimectics may be preferred to insulin treatment. First, the risk of hypoglycaemia is less if not combined with SU. Secondly, the body weight is usually decreased while insulin treatment increases weight. Patients not responding to GLP-1 mimetics or experiencing significant side effects will be treated with insulin. Irrespective of the policy used for the drug treatment of type 2 diabetes, exercise and proper diet will remain important for optimization of metabolic control.
No preview · Article · Feb 2008 · Acta Physiologica
[Show abstract][Hide abstract] ABSTRACT: Determine if pre-emptive daily insulin glargine surpasses regular insulin when needed for glycaemic control after cardiac surgery.
Prospective, randomized study of 43 patients (scheduled for coronary artery bypass grafting) with preoperatively diagnosed diabetes (DM) or pre-DM. Lantus group received insulin glargine daily from start of surgery while Actrapid group received regular insulin (sliding scale) when needed (plasma glucose (P-glu)>10 mmol/l). Primary endpoint was percent of pre- and post-prandial P-glu values within Target Intervals: Pre-prandial P-glu: 4.5-7 mmol/l; post-prandial P-glu: 4.5-9 mmol/l. Study period 1-4 days after surgery. Tissue glucose was also measured continuously.
More than twice as many P-glu values were within Target Interval for Lantus patients as compared with Actrapid patients (p<0.001). One of 504 timed measurements was <4 mmol/l. Area under the curve for glucose>7 mmol/l was reduced by 61% by Lantus (p<0.001).
The routine protocol with pre-emptive glargine insulin studied here provides a major improvement in glycaemic control with a minimal incidence of hypoglycaemia and without an excessive increase in nursing burden.
No preview · Article · Feb 2008 · Scandinavian Cardiovascular Journal
[Show abstract][Hide abstract] ABSTRACT: Defective beta-cell function with resulting impairment of glucose-stimulated insulin release is a critical factor in the pathogenesis of type 2 diabetes. Accumulated studies in pancreatic islets of the spontaneously diabetic Goto-Kakizaki (GK) rat suggest that this is a useful animal model of type 2 diabetes. The GK rat is non-obese, and abnormal glucose regulation develops early in life in association with impaired insulin secretion. There are some differences in islet morphology and function reported between different GK rat colonies. In addition to reduction of beta-cell mass, a number of beta-cell defects have been described with possible relevance for the reduced insulin secretion. Interestingly, some of these defects have also been shown in isolated islets from type 2 diabetic humans. The polygenic nature of diabetes heredity in the GK rat may well resemble the genetic basis in the majority of patients with type 2 diabetes. Here, we review studies concerning beta-cell function and islet gene expression in the GK rat and compare it with the limited number of investigations on similar topics in isolated islets from patients with type 2 diabetes.
Preview · Article · Dec 2007 · Diabetes Obesity and Metabolism
[Show abstract][Hide abstract] ABSTRACT: The mechanism by which the novel, pure glucose-dependent insulinotropic, imidazoline derivative BL11282 promotes insulin secretion in pancreatic islets has been investigated. The roles of KATP channels, alpha2-adrenoreceptors, the I1-receptor-phosphatidylcholine-specific phospholipase (PC-PLC) pathway and arachidonic acid signaling in BL11282 potentiation of insulin secretion in pancreatic islets were studied. Using SUR1(-/-) deficient mice, the previous notion that the insulinotropic activity of BL11282 is not related to its interaction with KATP channels was confirmed. Insulinotropic activity of BL11282 was not related to its effect on alpha2-adrenoreceptors, I1-imidazoline receptors or PC-PLC. BL11282 significantly increased [3H]arachidonic acid production. This effect was abolished in the presence of the iPLA2 inhibitor, bromoenol lactone. The data suggest that potentiation of glucose-induced insulin release by BL11282, which is independent of concomitant changes in cytoplasmic free Ca2+ concentration, involves release of arachidonic acid by iPLA2 and its metabolism to epoxyeicosatrienoic acids through the cytochrome P-450 pathway.
No preview · Article · Dec 2007 · Cellular and Molecular Life Sciences CMLS