Markers of innate immune activity in patients with type 1 and type 2 diabetes mellitus and the effect of the anti-oxidant coenzyme Q10 on inflammatory activity.

Major long-term complications in patients with diabetes are related to oxidative stress, caused by the hyperglycaemia characteristic for diabetes mellitus. The anti-oxidant coenzyme Q10 (CoQ10) has therefore been proposed as a beneficial supplement to diabetes treatment. Apart from its anti-oxidative function, CoQ10 appears to modulate immune functions by largely unknown mechanisms. The aim of this study was therefore to investigate the effect of CoQ10 on antimicrobial peptides and natural killer (NK) cells, both innate immune components implicated in the pathogenesis of diabetes and diabetes-associated long-term complications such as cardiovascular disease. We determined serum levels of antimicrobial peptides and the phenotype of NK cells isolated from peripheral blood of patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM) and from healthy controls. In addition, the same parameters were determined in diabetic patients after a 12-week period of CoQ10 supplementation. Two antimicrobial peptides, the human cathelicidin antimicrobial peptide (CAMP) and the human beta defensin 1 (hBD1), were reduced in serum from patients with T1DM. This defect was not reversible by CoQ10 supplementation. In contrast, CoQ10 reduced the levels of circulating hBD2 in these patients and induced changes in subset distribution and activation markers in peripheral NK cells. The results of the present study open up novel approaches in the prevention of long-term complications associated to T1DM, although further investigations are needed.

Sitagliptin improves beta-cell function in patients with acute coronary syndromes and newly diagnosed glucose abnormalities--the BEGAMI study.

BACKGROUND: Newly detected impaired glucose tolerance (IGT) or type 2 diabetes mellitus (T2DM) are common in patients with acute coronary syndrome (ACS; i.e. unstable angina/myocardial infarction) and related to disturbed beta-cell function. The aim of this study is to test the hypothesis that treatment with a dipeptidyl peptidase-4 inhibitor initiated soon after a coronary event improves beta-cell function. METHODS: Acute coronary syndrome ACS patients with IGT or T2DM (n = 71), screened by oral glucose tolerance test (OGTT) 4-23 days (median 6 days) after hospital admission, were randomly assigned to sitagliptin 100 mg (n = 34) or placebo (n = 37) and treated for a duration of 12 weeks. All patients received lifestyle advice but no glucose-lowering agents other than the study drug. The study end-point was beta-cell function assessed using the insulinogenic index (IGI = ΔInsulin30 /ΔGlucose30 ), derived from an OGTT, and acute insulin response to glucose (AIRg) assessed by a frequently sampled intravenous glucose tolerance test. RESULTS: The IGI and AIRg did not differ at baseline between the sitagliptin and placebo groups (69.9 vs. 66.4 pmol mmol(-1) and 1394 vs. 1106 pmol L(-1) min(-1) respectively). After 12 weeks, the IGI was 85.0 in the sitagliptin and 58.1 pmol/mmol in the placebo group (P = 0.013) and AIRg was 1909 and 1043 pmol L(-1) min(-1) (P < 0.0001) in the sitagliptin and placebo groups respectively. Fasting glucose at baseline was 6.1 mmol L(-1) in sitagliptin-treated patients and 6.0 mmol L(-1) in those who received placebo compared with 5.8 and 5.9 mmol L(-1) respectively, after 12 weeks of treatment. Post load glucose metabolism improved in significantly more sitagliptin-treated patients compared with the placebo group (P = 0.003). Sitagliptin was well tolerated. CONCLUSION: Sitagliptin improved beta-cell function and glucose perturbations in patients with ACS and newly diagnosed glucose disturbances.

The endothelin receptor antagonist bosentan improves peripheral endothelial function in patients with type 2 diabetes mellitus and microalbuminuria: a randomised trial.

AIMS/HYPOTHESIS: Endothelial dysfunction is important in the development of vascular complications in diabetes. Patients with type 2 diabetes have increased production of the vasoconstrictor and pro-inflammatory peptide, endothelin-1. Short-term intra-arterial administration of endothelin antagonists improves endothelium-dependent vasodilatation in patients with type 2 diabetes. We tested the hypothesis that oral administration of the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria. METHODS: This placebo-controlled and double-blind study was performed on 46 patients with type 2 diabetes and microalbuminuria (urine albumin/creatinine ratio >3 mg/mmol) at a medical university department. Patients were randomised to bosentan, 125 mg two times per day (n = 28), or placebo (n = 28) for 4 weeks. The computer-generated randomisation code was kept in sealed envelopes. Patients and people doing examinations or assessing outcomes were blinded. The primary endpoint was change in microvascular endothelium-dependent vasodilatation, based on change in digital reactive hyperaemia index. The secondary endpoint was change in brachial artery flow-mediated vasodilatation. RESULTS: Reactive hyperaemia index increased from 1.73 ± 0.43 (mean ± SD) at baseline to 2.08 ± 0.59 at follow-up (p < 0.05) in the bosentan group (n = 22), but did not change in the placebo group (1.84 ± 0.49 to 1.87 ± 0.47; n = 24). The change in reactive hyperaemia index from baseline was greater in the bosentan group than in the placebo group (p < 0.05). Nitroglycerine-induced digital hyperaemia was not affected. Brachial artery flow-mediated vasodilatation and blood pressure did not change during treatment. CONCLUSIONS/INTERPRETATION: Oral treatment of 4 weeks duration with the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria.

Low serum 25-hydroxyvitamin D level predicts progression to type 2 diabetes in individuals with prediabetes but not with normal glucose tolerance.

AIMS/HYPOTHESIS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS/INTERPRETATION: 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.

Coenzyme Q10 prevents GDP-sensitive mitochondrial uncoupling, glomerular hyperfiltration and proteinuria in kidneys from db/db mice as a model of type 2 diabetes.

AIMS/HYPOTHESIS: Increased oxygen consumption results in kidney tissue hypoxia, which is proposed to contribute to the development of diabetic nephropathy. Oxidative stress causes increased oxygen consumption in type 1 diabetic kidneys, partly mediated by uncoupling protein-2 (UCP-2)-induced mitochondrial uncoupling. The present study investigates the role of UCP-2 and oxidative stress in mitochondrial oxygen consumption and kidney function in db/db mice as a model of type 2 diabetes. METHODS: Mitochondrial oxygen consumption, glomerular filtration rate and proteinuria were investigated in db/db mice and corresponding controls with and without coenzyme Q10 (CoQ10) treatment. RESULTS: Untreated db/db mice displayed mitochondrial uncoupling, manifested as glutamate-stimulated oxygen consumption (2.7 ± 0.1 vs 0.2 ± 0.1 pmol O(2) s(-1) [mg protein](-1)), glomerular hyperfiltration (502 ± 26 vs 385 ± 3 µl/min), increased proteinuria (21 ± 2 vs 14 ± 1, µg/24 h), mitochondrial fragmentation (fragmentation score 2.4 ± 0.3 vs 0.7 ± 0.1) and size (1.6 ± 0.1 vs 1 ± 0.0 µm) compared with untreated controls. All alterations were prevented or reduced by CoQ10 treatment. Mitochondrial uncoupling was partly inhibited by the UCP inhibitor GDP (-1.1 ± 0.1 pmol O(2) s(-1) [mg protein](-1)). UCP-2 protein levels were similar in untreated control and db/db mice (67 ± 9 vs 67 ± 4 optical density; OD) but were reduced in CoQ10 treated groups (43 ± 2 and 38 ± 7 OD). CONCLUSIONS/INTERPRETATION: db/db mice displayed oxidative stress-mediated activation of UCP-2, which resulted in mitochondrial uncoupling and increased oxygen consumption. CoQ10 prevented altered mitochondrial function and morphology, glomerular hyperfiltration and proteinuria in db/db mice, highlighting the role of mitochondria in the pathogenesis of diabetic nephropathy and the benefits of preventing increased oxidative stress.

Genetic and functional analyses of MRAS and HNF1A genes in diabetes and diabetic nephropathy.

Evidence has recently indicated that the MRAS and HNF1A genetic polymorphisms are associated with coronary artery disease. The MRAS and HNF1A genes are located on chromosomes 3q and 12q within the regions where associations with diabetes and diabetic nephropathy occur. We thus performed genetic and functional analyses of these two genes to evaluate their impacts on diabetes and diabetic nephropathy. MRAS and HNF1A genetic polymorphisms were genotyped in 1399 Czech subjects including non-diabetic controls (339), type 1 (243) and type 2 (817) diabetic patients with and without diabetic nephropathy using TaqMan allelic discrimination. Gene expression levels in the kidneys of diabetic Goto-Kakizaki and Wistar rats were detected with real-time RT-PCR. Despite no significance in genetic analysis of diabetic subjects, SNP rs2259816 in the HNF1A gene tended to associate with diabetic nephropathy in type 1 diabetic patients. The hnf1a gene expression was significantly decreased in kidney tissues of Goto-Kakizaki rats compared to Wistar and insulin-treated Goto-Kakizaki rats. There was neither significant association in the MRAS genetic polymorphism with diabetic nephropathy nor variation of mras gene expression in the kidneys of Goto-Kakizaki and Wistar rats. Data from the present study have not proved any significant association of the MRAS and HNF1A genetic polymorphisms with diabetes and diabetic nephropathy in a cohort of Czech population. However, the functional analysis and the trend in genetic analysis suggest that the HNF1A gene may have primary genetic impact on the development of diabetic nephropathy.

Treatment with low-dose prednisolone is associated with altered body composition but no difference in bone mineral density in rheumatoid arthritis patients: a controlled cross-sectional study.

OBJECTIVES: To determine whether low-dose prednisolone affects body composition and bone mineral density (BMD) in patients with rheumatoid arthritis (RA), also considering inflammation and physical disability. METHODS: This cross-sectional study included 100 patients (50 women) with RA with a median (IQR) disease duration of 8 (4-15) years. Fifty patients had been treated with prednisolone (5-7.5 mg) for at least 2 years (the P-group) and 50 patients matched for gender and age had not (the NoP-group). Body composition and BMD were assessed by dual-energy X-ray absorptiometry (DXA). Disease activity (28-joint Disease Activity Score, DAS28) and physical disability (Health Assessment Questionnaire, HAQ) were assessed. RESULTS: The total patient group had increased fat mass (FM) and a high trunk:peripheral fat ratio, of which 38% had a fat free mass index (FFMI, kg/m²) below the 10th percentile of a reference population. The P-group had significantly higher FM but similar lean body mass (LBM) and BMD compared with the NoP-group. In multivariate analyses, treatment with prednisolone and a higher HAQ score were significantly and independently associated with higher FM but not with LBM. Higher C-reactive protein (CRP) was independently associated with lower LBM. Higher HAQ score and low weight were significantly and independently associated with lower BMD at femoral neck and lumbar spine. CONCLUSIONS: RA patients treated with low-dose prednisolone had significantly higher FM than patients without prednisolone, an effect that was independent of current inflammation. However, there was no association between prednisolone treatment and muscle mass or BMD. Thus, the net effect of prednisolone on body composition and bone is different in inflammatory diseases such as RA.

Phototherapy with ultraviolet radiation: a study of hormone parameters and psychological effects.

BACKGROUND AND OBJECTIVES: Patients report well-being as they are treated with phototherapy. We investigated hormone parameters and psychological well-being after phototherapy in a placebo-controlled study. METHODS: A total of 77 patients with dermatological conditions and 22 healthy volunteers were divided into four groups. The patients received phototherapy either on the whole body or only on hands and/or feet. The volunteers were given either whole-body phototherapy or placebo light. Serum or plasma samples were analysed for cortisol, calcium, magnesium, phosphate, TSH, T(4), T(3) and 25-hydroxyvitamin D, and urine samples for cortisol. Patients and volunteers answered a questionnaire before and 6 weeks after phototherapy/placebo light. Psychiatric ratings were performed according to the Comprehensive Psychopathological Self-rating Scale for Affective Syndromes, a self-report version of which has been transformed to correspond to the Montgomery-Asberg Depression Rating Scale (MADRS). RESULTS: In the patients who received whole-body irradiation, we observed a significant improvement in both MADRS score and cognitive-symptom score after the completion of phototherapy. We also observed a significantly higher level of 25-hydroxyvitamin D after phototherapy, but no difference in the other hormone parameters. CONCLUSION: Whole-body phototherapy of patients with dermatological conditions results in improved well-being and significantly higher levels of 25-hydroxyvitamin D in serum.

Low levels of insulin-like growth-factor-binding protein-1 (IGFBP-1) are prospectively associated with the incidence of type 2 diabetes and impaired glucose tolerance (IGT): the Söderåkra Cardiovascular Risk Factor Study.

AIM: To explore the association between baseline levels of insulin-like growth-factor-binding protein-1 (IGFBP-1), a marker of insulin sensitivity, and the development of type 2 diabetes or impaired glucose tolerance (IGT) in a specifically defined middle-aged population. METHODS: This cross-sectional population-based screening study was conducted in 1989-1990 and included baseline data for 664 non-diabetic subjects aged 40-59 years. Clinical data were collected and blood samples analyzed for blood glucose, serum lipids and insulin. Blood specimens were frozen at baseline and later analyzed for IGF-I, IGFBP-1 and C-reactive protein (CRP). At the follow-up in 2006, the incidence of type 2 diabetes and IGT was reported based on primary-care medical records. RESULTS: During the 17-year observation period, 42 subjects (6.3%) developed type 2 diabetes/IGT. Those in the lowest quintile of IGFBP-1 (< or =24 microg/L) at baseline had a diabetes incidence of 12.6% while, in the highest quintile of IGFBP-1 (> or =59 microg/L), the incidence was 1.5%. Cox's proportional-hazards model regression analyses were used to determine the incidence of type 2 diabetes/IGT, corrected for age and gender, in relation to IGFBP-1, CRP and waist circumference. Subjects in the lowest IGFBP-1 quintile showed an independently increased risk of type 2 diabetes/IGT [hazards ratio (HR): 3.54; 95% CI 1.18-10.6; P=0.024]. For CRP and waist circumference, the corresponding figures were HR: 6.81; 95% CI 2.50-18.6; P<0.001 and HR: 3.33; 95% CI 1.47-7.6; P=0.004, respectively. CONCLUSION: Low levels of IGFBP-1 predicted the long-term development of type 2 diabetes or IGT in a middle-aged population. The association was independent of CRP and abdominal obesity.

Correlation of serum IGF-I and IGFBP-1 and -3 to cardiovascular risk indicators and early carotid atherosclerosis in healthy middle-aged men.

OBJECTIVES: IGF-I, IGFBP-1 and IGFBP-3 are putative mediators in cardiovascular disease. The present study examined (i) the correlations of circulating IGF-I, IGFBP-1 and IGFBP-3 to established cardiovascular risk factors and signs of early atherosclerosis as reflected by ultrasound measurement of common carotid intima-media thickness (IMT), and (ii) whether serum concentrations of these analytes are modulated during alimentary lipaemia. DESIGN: Cross-sectional clinical study. PATIENTS: A biobank and clinical database based on 96 healthy Caucasian men, aged 50 years, with an apolipoprotein (apo) E3/E3 genotype, who had originally undergone investigations of postprandial lipoprotein metabolism was used for the study. MEASUREMENTS: Total IGF-I, IGFBP-1 and IGFBP-3 were determined in serum by radioimmunoassay (RIA). Free IGF-I was measured by a commercial two-site immunoradiometric assay (IRMA). RESULTS: In multivariate analyses, fasting serum free IGF-I correlated inversely with IMT and accounted for 5% of the variation in multiple R(2). When fasting serum IGFBP-1 was entered in the models instead of IGF-I, IGFBP-1 correlated positively with IMT and accounted for 6% of the variation in IMT. IGFBP-3 and total IGF-I were unrelated to IMT. There were no associations between free IGF-I and cardiovascular risk factors, whereas IGFBP-1 behaved like a component of the insulin resistance syndrome. Serum free IGF-I increased and IGFBP-1 decreased postprandially. CONCLUSION: The data indicate that serum free IGF-I and IGFBP-1 are implicated in early atherosclerosis.

Cachexia in rheumatoid arthritis is associated with inflammatory activity, physical disability, and low bioavailable insulin-like growth factor.

OBJECTIVES: To examine the impact of inflammation, insulin-like growth factor (IGF-1) and its regulating binding protein (IGFBP-1) on lean body mass (LBM) in patients with rheumatoid arthritis (RA). METHODS: In 60 inpatients (50 women), inflammatory activity was measured by Disease Activity Score 28 (DAS28), C-reactive protein (CRP), and interleukin (IL)-6, and physical disability by the Health Assessment Questionnaire (HAQ). LBM was assessed by dual-energy X-ray absorptiometry (DXA) and fat free mass index (FFMI; kg/m(2)) and fat mass index (FMI; kg/m(2)) were calculated. RESULTS: Median age was 65 years and disease duration 13 years. Fifty per cent of the patients had FFMI below the 10th percentile of a reference population and 45% had FMI above the 90th percentile, corresponding to the condition known as rheumatoid cachexia (loss of muscle mass in the presence of stable or increased FM). DAS28, CRP, and IL-6 correlated negatively with LBM (p = 0.001, 0.001, and 0.018, respectively), as did HAQ (p = 0.001). Mean (confidence interval) IGF-1 was in the normal range, at 130 (116-143) microg/L. IGFBP-1 levels were elevated in patients (median 58 microg/L in women and 59 microg/L in men) compared with a normal population (33 microg/L in women and 24 microg/L in men). The ratio IGF-1/IGFBP-1, which reflects bioavailable IGF-1, was low (2.0 microg/L) and was positively correlated with LBM (p = 0.015). In multiple regression analysis, 42% of the LBM variance was explained by IGF-1/IGFBP-1, HAQ score, and DAS28. CONCLUSION: A large proportion of RA inpatients, mainly women, had rheumatoid cachexia. The muscle wasting was explained by inflammatory activity and physical disability as well as low bioavailable IGF-1.

Longitudinal study of the maternal insulin-like growth factor system before, during and after pregnancy in relation to fetal and infant weight.

BACKGROUND: The maternal insulin-like growth factor (IGF) system is considered to be involved in fetal growth regulation. However, available data linking this system to fetal growth are contradictory and incomplete. AIMS: To measure components of the IGF system before, during and after pregnancy in healthy women and to relate these results, and their changes during pregnancy, to fetal weight (gestational week 31) and birth weight. METHODS: Serum concentrations of IGF-I, IGF-II, IGF-binding protein (IGFBP)-1, IGFBP-3 and IGFBP-3 protease activity were assessed in 23 women before conception, at weeks 8, 14, 20, 32 and 35 of pregnancy and 2 weeks postpartum. The data were analyzed using simple and multiple linear regression. RESULTS: One third of the variability in fetal weight was explained by IGF-I in combination with IGFBP-3 protease activity, both assessed at gestational week 32 (p = 0.013). Birth weight was negatively correlated (r = -0.43 to -0.59) with IGFBP-1 at gestational week 20 (p = 0.041), 32 (p = 0.012) and 35 (p = 0.003). CONCLUSION: We propose there is a finely tuned balance among the components of the IGF system, providing a means for fetal growth regulation.

GHR exon 3 polymorphism: association with type 2 diabetes mellitus and metabolic disorder.

Growth hormone (GH) signaling via the growth hormone receptor (GHR) forms a major part of the GH-IGF-I axis, which is crucial for controlling metabolism and anabolism. Two common variants of the GHR differ by the presence (full length or GHR(fl)) or absence of exon 3 (exon 3 deleted or GHR(d3)), the function of which is unknown. However, differential response to GH treatment has been observed with carriers of the GHR(d3) variant conferring a greater growth rate. This study investigates these GHR variants in subjects with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT), including Type 2 diabetes mellitus (T2DM). DNA was extracted from blood samples from subjects with NGT (n=158), IGT (n=116) and T2DM (n=194). The T2DM subjects in set 1 (n= 39) were newly diagnosed, whilst those in set 2 (n=155) had a mean duration of 7 years. Set 1 also included NGT and IGT subjects. Genotyping by standard PCR and gel electrophoresis were carried out. A significant difference was observed between T2DM and NGT (p<0.0001) with a significantly lower frequency of GHR(d3) in T2DM (3.6% compared to 17% in NGT). Both sets of T2DM subjects with at least one GHR(d3) allele had significantly higher BMI. In the larger subset of T2DM, GHR(d3) was associated with higher CRP levels as well as age adjusted IGF-I, with a trend of higher C-peptide secretion and impaired lipid levels, indicating a phenotype with metabolic disorder when compared to the GHR(fl/fl) T2DM subjects. In conclusion, homozygosity for the GHR(d3) allele appears to be preventive of T2DM. However, when other factors cause overt T2DM, the GHR(d3) allele confers a phenotype indicative of metabolic disorder. This study supports the hypothesis that the two GHR alleles by their inclusion or exclusion of exon 3 are functionally different.

Serum insulin-like growth factor-I level is independently associated with coronary artery disease progression in young male survivors of myocardial infarction: beneficial effects of bezafibrate treatment.

OBJECTIVES: We investigated whether the effect of bezafibrate on progression of coronary atherosclerosis in the BEzafibrate Coronary Atherosclerosis Intervention Trial (BECAIT) was related to insulin-like growth factor (IGF)-I and glucose-insulin homeostasis. BACKGROUND: BECAIT, the first double-blind, placebo-controlled, randomized, serial angiographic trial of a fibrate compound, demonstrated that progression of focal coronary atherosclerosis in young patients after infarction could be retarded by bezafibrate treatment. METHODS: The treatment effects on serum concentrations of IGF-I and insulin-like growth factor binding protein (IGFBP)-1, as well as on basal and postload glucose and insulin levels, were examined, and on-trial determinations were related to the angiographic outcome measurements. RESULTS: Bezafibrate treatment resulted in a significant reduction of serum IGF-I levels, both at two and five years, and on-trial serum IGF-I levels were directly related to changes in both minimal lumen diameter (r = 0.25, p < 0.05) and mean segment diameter (r = 0.29, p < 0.05). In contrast, none of the available indexes of insulin resistance (homeostasis model assessment estimate, basal and postload plasma insulin concentrations and serum IGFBP-1 levels) were related to the angiographic changes, nor were they significantly affected by bezafibrate treatment. Multiple stepwise regression analysis showed that the relation between on-trial serum IGF-I level and coronary artery disease (CAD) progression was independent of baseline angiographic score, age, body mass index, serum lipoprotein and plasma fibrinogen concentrations and measures of glucose-insulin homeostasis. CONCLUSIONS: IGF-I could be implicated in the progression of premature CAD, and a reduction of serum IGF-I concentration could account partly for the effect of bezafibrate on progression of focal coronary atherosclerosis.

Measurement of glucose and metabolites in subcutaneous adipose tissue during hyperglycemia with microdialysis at various perfusion flow rates.

BACKGROUND: Microdialysis-based glucose sensors have recently been introduced for monitoring glucose levels in diabetic patients. The flow rate by which the fluid sample is pumped through the microdialysis catheter varies in different studies. AIM: To study the effects of various flow rates on glucose and its metabolites sampled by microdialysis during an oral glucose tolerance test. MATERIAL, METHODS: Glucose, lactate, pyruvate and glycerol were measured with microdialysis in interstitial fluid of subcutaneous adipose tissue in twelve healthy young subjects before and during an oral glucose tolerance test using four different flow rates (0.3, 1, 2 and 5 microL/min) and a 30 mm dialysis membrane. RESULTS: At the basal fasting state the dialysate glucose obtained by 0.3 microL/min was equal to capillary glucose concentration. A decrease in dialysate glucose levels during the basal state was observed for higher flow rates but not for 0.3 microL/min, which indicates a depleting effect. The relative increase after OGTT was similar for capillary glucose and flow rate 0.3 microL/min but not for higher flow rates. CONCLUSION: The low microdialysis flow rate (0.3 microL/min) facilitates the capture of true interstitial glucose concentrations during glucose fluctuations. Thus this low flow rate is preferred in studies of local tissue metabolism.

Leu7Pro polymorphism in the neuropeptide Y (NPY) gene is associated with impaired glucose tolerance and type 2 diabetes in Swedish men.

The neuropeptide Y (NPY) is a neuropeptide with a role in the regulation of satiety and energy balance of body weight, insulin release, cardiovascular and central endocrine systems. In order to evaluate whether the NPY gene variations contribute to development of type 2 diabetes (T2DM), we have performed a genetic association study for Leu7Pro (T1128 C) polymorphism of the NPY gene in impaired glucose tolerance (IGT) and T2DM. Genotyping experiments for this non-synonymous single nucleotide polymorphism (SNP) in 263 patients with T2DM, 309 subjects with IGT and 469 non-diabetic healthy individuals in Swedish Caucasians were performed by using Dynamic Allele Specific Hybridisation (DASH). We found that the frequencies of the "risk" allele C in the subjects with IGT and the patients with T2DM in Swedish men were 13 % (p = 0.002, OR = 3.70, 1.65 - 8.29 95 % CI) and 10 % (p = 0.007, OR = 4.80, 1.47 - 11.33 95 % CI) respectively, which were significantly higher than the C allele frequency in non-diabetic controls (6 %). Furthermore, we found that the carriers with TC and CC genotypes in the subjects with IGT in Swedish men had significantly higher fasting plasma glucose in comparison with the TT carriers (5.6 +/- 0.7 mmol/l vs. 5.2 +/- 0.7 mmol/l, p = 0.021). The present study thus provides the evidence that Leu7Pro polymorphism in the NPY gene is associated with IGT and T2DM in Swedish men, and indicates that the NPY gene variations contribute to development of T2DM. Questions of gender specificity may be explained by genetic backgrounds, sense of coherence for stress and other factors in environment.

Determinants of growth in diabetic pubertal subjects.

OBJECTIVE: To analyze the relationship among metabolic control, IGF-I, and growth in pubertal diabetic subjects. RESEARCH DESIGN AND METHODS: In 72 diabetic children, we have studied the pattern of change of IGF-I, IGF-I SD score, IGF binding protein (BP)-1, and growth rate in different pubertal stages and have analyzed their relation to age sex, weight/length index, HbA1c, insulin concentration, insulin dose, and dehydroepiandrosteronesulfate (DHEAS). RESULTS: The serum IGF-I values increased up to Tanner stage 4 and thereafter decreased, whereas IGFBP-1 showed the inverse pattern. When transforming the IGF-I values into SD scores, correcting for age, sex, and pubertal stage, it was shown that the deviation from normal values increased with increasing pubertal stage in boys, but was equal in stages 3-5 in girls. Using multiple regression analysis, HbA1c, insulin dose, and DHEAS were significantly correlated to IGF-I SD score (R2 = 0.253, P = 0.001). IGFBP-I levels in the afternoon were within normal range. LogIGFBP-1 showed an inverse correlation, to insulin concentration in single correlation (r = -0.26, P = 0.02). In single correlation, growth rate correlated significantly to insulin dose (r = 0.25, P = 0.03). In a multiple regression analysis, only DHEAS and IGF-I SD score were found to be significantly correlated to growth rate (R2 = 0.370, P < 0.001). The 18 adolescents who had reached their final height did not deviate from their target final height, according to their recorded growth since birth. CONCLUSIONS: In a group of fairly well-controlled diabetic children, the normal increase in IGF-I during puberty is blunted. Despite decreased IGF-I levels, target final height was attained, probably because of adequate insulin compensation leading to normal IGFBP-l, thus adequate bioavailability of IGF-I. Our results point out the importance of sufficient exogenous insulin in the period of rapid linear growth.

Transcutaneous oxygen tension and toe blood pressure as predictors for outcome of diabetic foot ulcers.

OBJECTIVE: The present study was undertaken to compare the predictive values of transcutaneous oxygen tension (TcPO2) and toe blood pressure (TBP) measurements for ulcer healing in patients with diabetes and chronic foot ulcers. RESEARCH DESIGN AND METHODS: Investigated prospectively were 50 diabetic patients (37 men) with chronic foot ulcers. The age was 61 +/- 12 (mean +/- SD), and the diabetes duration was 26 +/- 14 years. TBP (mmHg) was measured in dig I and TcPO2 (mmHg) at the dorsum of the foot. Ulcer healing was continuously evaluated by measuring the ulcer area every 4-6 weeks. After a follow-up time of 12 months, the patients were divided into three groups according to clinical outcome: healed with intact skin, improved ulcer healing, or impaired ulcer healing. RESULTS: Of the 13 patients who deteriorated, 11 had TcPO2 < 25 mmHg, while 34 of the 37 patients who improved had TcPO2 > or = 25 mmHg. The sensitivity and specificity for TcPO2 were 85 and 92%, respectively, when a cutoff level of 25 mmHg was used for determination of outcome of ulcer healing (healing or nonhealing). The corresponding values for TBP at 30 mmHg were 15 and 97%. Measurement of TcPO2 provided a higher positive predictive value (79%) than TBP (67%). CONCLUSIONS: The results indicate that TcPO2 is a better predictor for ulcer healing than TBP in diabetic patients with chronic foot ulcers, and that the probability of ulcer healing is low when TcPO2 is < 25 mmHg.

Glucocorticoids and Sarcoidosis: A Longitudinal Study on the Effects on Cortical and Trabecular Bone.

BACKGROUND: Glucocorticoid induced osteoporosis is a well-known side effect of glucocorticoid treatment. In sarcoidosis the impact on bone by glucocorticoid treatment is complex due to hormonal disturbances of calcium and vitamin-D, which by itself may cause bone loss. In this study we aimed to investigate the longitudinal impact of glucocorticoids on cortical and trabecular bone in patients with mild, recently diagnosed sarcoidosis. METHODS: Ten patients (8 females; mean age 44 (±13)) were studied during one year of glucocorticoid treatment. The assessment of mainly cortical to purely trabecular bone was made by dual X-ray absorptiometry (DXA) of the spine and hip, quantitative ultrasound of the calcaneus, and magnetic resonance relaxometry of the spine and calcaneus. Bone and hormonal measurements were performed at baseline, after 3, 6, and 12 months, and baseline, 3 weeks and 3 months, respectively. RESULTS: DXA of the spine, decreased from baseline at 6 months (P=0.01). R2' of the calcaneus decreased with time (B: -3.6;P=0.03). In the females (n=8) there was a significant decrease in DXA of the spine when comparing 3 months and 6 months (P=0.03), and 3 months and 12 months (P=0.02) and a decrease in R2'of the calcaneus from baseline to 12 months (P=0.01). There was no change in hormonal levels. CONCLUSION: Treatment of initial mild sarcoidosis with dose tapered glucocorticoid therapy only mildly affects the final trabecular and cortical bone and hormone levels. Dose tapering is an important part in glucocorticoid therapy, likely contributing to the mild effects on bone observed in this study.

Glucagon stimulates insulin-like growth factor binding protein-1 secretion in healthy subjects, patients with pituitary insufficiency, and patients with insulin-dependent diabetes mellitus.

Glucagon (1-1.5 mg) was administrated iv as a bolus dose to healthy individuals (n = 7), patients with GH deficiency (n = 14), and patients with insulin-dependent diabetes mellitus (IDDM; n = 6). Thereafter, blood samples for determination of serum glucose, insulin, insulin-like growth factor-binding protein-1 (IGFBP-1), GH, and insulin-like growth factor-I (IGF-I) concentrations were collected for 180 min. IGFBP-1 concentrations increased significantly in response to glucagon, with maximal values observed at 90 min [in healthy subjects from 36 +/- 6 to 58 +/- 10 micrograms/L (P < 0.05), in GH-deficient patients from 36 +/- 4 to 54 +/- 6 micrograms/L (P < 0.001), and in IDDM patients from 115 +/- 18 to 167 +/- 27 micrograms/L (P < 0.05)]. The IGFBP-1 elevation was delayed in relation to the glucagon-induced increase in glucose and insulin concentrations. When the groups were combined, the individual IGFBP-1 peak value observed at 90 min was inversely correlated to the individual peak value of insulin observed at 15-30 min (r = -0.743; P < 0.001). In GH-deficient patients, serum GH concentrations remained undetectable (< 0.2 micrograms/L), and IGF-I concentrations were unchanged after the glucagon injection. In healthy subjects and IDDM patients, mean GH levels did not change significantly, whereas mean IGF-I concentrations decreased slightly at 30 min. In conclusion, glucagon increased serum IGFBP-1 concentrations in spite of increases in glucose and insulin. These results suggest that glucagon is a stimulator of IGFBP-1.