Improved physiological properties of gravity-enforced reassembled rat and human pancreatic pseudo-islets

Previously we demonstrated the superiority of small islets vs large islets in terms of function and survival after transplantation, and we generated reaggregated rat islets (pseudo-islets) of standardized small dimensions by the hanging-drop culture method (HDCM). The aim of this study was to generate human pseudo-islets by HDCM and to evaluate and compare the physiological properties of rat and human pseudo-islets. Isolated rat and human islets were dissociated into single cells and incubated for 6-14 days by HDCM. Newly formed pseudo-islets were analysed for dimensions, morphology, glucose-stimulated insulin secretion (GSIS) and total insulin content. The morphology of reaggregated human islets was similar to that of native islets, while rat pseudo-islets had a reduced content of α and δ cells. GSIS of small rat and human pseudo-islets (250 cells) was increased up to 4.0-fold (p < 0.01) and 2.5-fold (p < 0.001), respectively, when compared to their native counterparts. Human pseudo-islets showed a more pronounced first-phase insulin secretion as compared to intact islets. GSIS was inversely correlated to islet size, and small islets (250 cells) contained up to six-fold more insulin/cell than large islets (1500 cells). Tissue loss with this new technology could be reduced to 49.2 ± 1.5% in rat islets, as compared to the starting amount. With HDCM, pseudo-islets of standardized size with similar cellular composition and improved biological function can be generated, which compensates for tissue loss during production. Transplantation of small pseudo-islets may represent an attractive strategy to improve graft survival and function, due to better oxygen and nutrient supply during the phase of revascularization. Copyright © 2014 John Wiley & Sons, Ltd.

Glucose control during a driving training in patients with type 1 and type 2 diabetes mellitus - a randomised, controlled trial

AIM

To investigate the effect of prolonged acute mental stress by means of a driving training on glucose control in patients with type 1 and type 2 diabetes mellitus.

METHODS

39 patients with insulin-treated diabetes (18 type 1, 21 type 2 diabetes) were exposed to mental stress by means of a 2 h-driving training. The training session started 15 min after intake of a standard meal. Blood glucose, blood pressure, heart rate, salivary cortisol, and subjective stress perception were monitored in regular intervals and compared to a control day.

RESULTS

On the stress testing day, blood pressure rose from 142/86±16/9 mmHg to 162/95±22/11 mmHg (p<0.001), heart rate from 72±11 bpm to 86±16 bpm (p<0.001) and subjective stress perception from 1.4±0.6 to 4.7±2.5 points (p<0.001). Salivary cortisol concentrations increased from a median of 5.1 nmol/l (Interquartile Range (IQR) 3.5-7.5 nmol/l) at baseline to 7.7 nmol/l (IQR 4.7-12.8 nmol/l, p<0.001), all these measurements remained stable on the control day. Glucose control showed no significant difference on the stress testing day compared to the control day (mean difference over time=0.22 mmol/l, 95%-CI -1.5 to +1.9 mmol/l, p=0.794). A multivariate linear regression and correlation analysis showed no association of demographic characteristics (diabetes type, age, body mass index (BMI), diabetes duration, HbA1c), objective or subjective stress parameters with the course of glucose concentrations during the driving training.

CONCLUSIONS

Although a 2 h-driving training causes increased subjective and objective stress parameters, glucose control is maintained in patients with insulin-treated diabetes.

Smoking is associated with impaired long-term glucose metabolism in patients with type 1 diabetes mellitus

BACKGROUND AND AIMS

Smoking is known to negatively influence glucose metabolism both in healthy subjects and in patients with diabetes. The aim of this study was to compare glycemic control in patients with type 1 diabetes mellitus who were smokers with those who did not smoke during a prospective long-term follow-up.

METHODS AND RESULTS

In a single center, 763 patients with type 1 diabetes mellitus were included, 160 (21.0%) of them were smokers. Patients were treated with intensive insulin therapy according to existing guidelines. Glucose control was monitored quarterly, diabetes related complications and cardiovascular risk factors were assessed at least once a year. Glucose control in smokers was significantly worse than in non-smokers at baseline and during follow-up (mean HbA1c during 5047 patient-years of follow-up 7.9 ± 1.3% in smokers and 7.3 ± 1.1% in non-smokers, p < 0.001) despite a higher insulin dosage in smokers (0.71 ± 0.30 U/kg vs. 0.65 ± 0.31 U/kg in non-smokers, p = 0.046). HDL cholesterol was lower in smokers at baseline (1.53 ± 0.45 vs. 1.68 ± 0.51 in non-smokers, p = 0.048). Diabetes related complications tended to occur with a higher frequency in smokers, with a significant difference in macroalbuminuria (9.8% vs. 4.8% in non-smokers, p = 0.047).

CONCLUSION

Smoking is associated with worse glucose control in patients with type 1 diabetes mellitus despite the same treatment strategies as in non-smokers. Hyperglycemia, therefore, may contribute to an earlier incidence of diabetes related complications in these patients, in addition to direct toxic effects of smoking.

Effect of psychological stress on glucose control in patients with Type 2 diabetes

AIM

To investigate the effect of acute psychological stress on glucose concentrations in patients with Type 2 diabetes, in the fasting state as well as in the postprandial state.

METHODS

Thirty patients (12 female) with Type 2 diabetes were included. Mean ± SD age was 60 ± 12 years, BMI 28.8 ± 4.2 kg/m(2), diabetes duration 8.9 ± 6.7 years and HbA(1c) 51 ± 9 mmol/mol (6.8 ± 0.8%). Using a non-randomized approach, all participants were exposed to moderate psychological stress by means of the Trier Social Stress Test: 10 participants in the fasting state and 20 participants 75 min after intake of a standard meal. Blood pressure, heart rate and salivary cortisol were monitored on the control day and the stress-test day. Glucose concentrations were assessed using a continuous glucose monitoring system.

RESULTS

On the stress-test day, blood pressure rose from 117/73 ± 13/12 to 155/92 ± 22/14 mmHg, heart rate from 77 ± 11 to 91 ± 25 b min(-1) and salivary cortisol concentrations from 8.5 ± 3.7 to 26.4 ± 12.1 nmol/l (P < 0.001); these measurements remained unchanged on the control day. On the stress-test day, when the Trier Social Stress Test was applied 75 min after the intake of a standard meal, the glucose concentrations were significantly higher compared with the control day (mean difference 1.5 mmol/l, 95% CI 0.5-2.4, P = 0.003). In the fasting state, glucose concentrations slightly decreased during the control day but remained stable on the stress-test day (mean difference compared with the control day 0.7 mmol/l, 95% CI -0.7 to 2.0, P = 0.31).

CONCLUSIONS

When stress is experienced in the postprandial period, acute psychological stress significantly increases glucose concentrations in patients with Type 2 diabetes.

ER stress in adipocytes inhibits insulin signaling, represses lipolysis, and alters the secretion of adipokines without inhibiting glucose transport

The endoplasmic reticulum (ER) is the intra-cellular site, where secreted and membrane proteins are synthesized. ER stress and activation of the unfolded protein response (UPR) contribute to insulin resistance and the development of diabetes in obesity. It was shown previously in hepatocytes that the UPR activates c-jun N-terminal kinase (JNK), which phosphorylates insulin receptor substrate (IRS) proteins on serine residues thereby inhibiting insulin signal transduction. Here we describe how ER stress affects insulin signaling and the biological function of adipocytes. In addition to inhibition of IRS we found that ER stress downregulates the expression of the insulin receptor. Concomitantly, insulin-induced activation of Akt/PKB and of ERK1/2 was strongly inhibited. Ectopic expression of IRS1 or IRS2 strongly counteracted the inhibitory effect of ER stress on insulin signaling while pharmacological inhibition of JNK with SP600125 resulted only in a mild improvement. ER stress decreased the secretion of the adipokines adiponectin and leptin, but strongly increased secretion of IL-6. ER stress inhibited expression and insulin-induced phosphorylation of AS160, reduced lipolysis but did not inhibit glucose transport. Finally, supernatants collected from 3T3-L1 adipocytes undergoing ER stress improved or impaired proliferation when used to condition the culture medium of INS-1E beta-cells dependent on the degree of ER stress. It appears that ER stress in adipocytes might initially lead to changes resembling early prediabetic stages, which at least in part support the regulation of systemic energy homeostasis.

Interleukin-18 levels are associated with low-density lipoproteins size

INTRODUCTION

Both low-density lipoproteins (LDL) size and serum interleukin (IL)-18 levels have been shown to be predictors of cardiovascular morbidity and mortality. However, it is still unknown whether IL-18 levels are independently associated with LDL size.

METHODS

In this cross-sectional study including 53 premenopausal women (18-45 years), LDL size (by gradient gel electrophoresis), serum IL-18, high-sensitivity C-reactive protein (hs-CRP), serum lipids, insulin sensitivity (S(I), by frequently sampled intravenous glucose tolerance test) were measured.

RESULTS

LDL size correlated with IL-18 (r = -0.38, P = 0.006), hs-CRP (r = -0.40, P = 0.003), S(I) (r = 0.36, P = 0.011), serum triglycerides (r = -0.32, P = 0.018) and high-density lipoproteins (HDL)-cholesterol (r = 0.40, P = 0.003). When these variables were entered into a regression model, serum IL-18 (beta = -0.26, P = 0.04), triglycerides (beta = -0.29, P = 0.02) and HDL-cholesterol (beta = 0.34, P = 0.01) levels were independently associated with LDL size, accounting for 42% of the variance (P < 0.001). Serum hs-CRP levels and S(I) were not significant independent predictors of LDL size in this model.

CONCLUSIONS

This is the first report showing that elevated IL-18 levels are associated with reduced LDL size, independent of other inflammatory and metabolic risk factors. Future prospective studies are needed to evaluate the predictive role of IL-18 as an inflammatory marker of LDL size and the development of subclinical and/or clinical atherosclerosis.

Quantitative and qualitative effects of rosuvastatin on LDL-cholesterol: what is the clinical significance?

BACKGROUND

Statins have emerged as the global leader in pharmacologic therapy for dyslipidaemia, and rosuvastatin has demonstrated clinical efficacy as well as safety in several clinical trials and postmarketing analyses.

AIM

The present article reviewed the effects of rosuvastatin on the quantity and the quality of low-density lipoproteins (LDL).

METHODS

We searched for and reviewed all the available evidence in a systematic way. A literature search (by Medline and Scopus) was performed using the following headings: 'LDL-cholesterol', 'LDL size', 'LDL subclasses', 'small dense LDL', 'apolipoprotein B, apo B' and 'rosuvastatin' up to 11 November 2008. The authors also manually reviewed the references of selected articles for any pertinent material.

RESULTS

Rosuvastatin reduces LDL-cholesterol levels to a greater extent than other statins and is able to modulate significantly LDL size and subclasses towards less atherogenic particles as well as the LDL particle number, as indirectly measured by the levels of apo B.

DISCUSSION AND CONCLUSIONS

The recent Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin study provides more evidence about the effectiveness of rosuvastatin therapy in reducing cardiovascular risk, even among persons who would not currently be considered for pharmacotherapy. Further insights on cardiovascular outcomes will be available by the on-going trials included in the GALAXY program that includes subjects with type-2 diabetes, haemodialysis recipients, patients with congestive heart failure and specific ethnic groups, such as African American, Hispanic and South Asian populations.

Atherogenic forms of dyslipidaemia in women with polycystic ovary syndrome

OBJECTIVE

Dyslipidaemia is very common in patients with polycystic ovary syndrome (PCOS) but, beyond plasma lipids, atherogenic lipoprotein (Lp) and apolipoprotein (apo) alterations are still ill defined.

DESIGN

We measured concentrations of apoB, Lp(a) and small, dense low-density lipoprotein (LDL) in 42 patients with PCOS [age: 28 +/- 7 years, body mass index (BMI): 27 +/- 5 kg/m(2)] vs. 37 age- and BMI-matched healthy controls.

METHODS

Elevated Lp(a) levels considered were those > 30 mg/dl while elevated apoB concentrations were those > 100 g/l.

RESULTS

Polycystic ovary syndrome showed increased triglycerides levels (p = 0.0011) and lower high-density lipoprotein (HDL)-cholesterol concentrations (p = 0.0131) while total- and LDL cholesterol were similar. PCOS also showed smaller LDL size (p = 0.0005), higher levels of total small, dense LDL (p < 0.0001), higher concentrations of Lp(a), as considered as absolute values (p = 0.0143) and log-transformed (p = 0.0014), while no differences were found in apoB levels. Elevated Lp(a) concentrations were found in 24% of PCOS, while elevated apoB levels were relatively uncommon (14%). Spearman correlation analysis revealed that Lp(a) concentrations were weakly correlated only with HDL-cholesterol levels (r = -0.378, p = 0.0431). In addition, 36% of patients with PCOS with normal plasma lipid profile showed elevated levels of Lp(a), apoB or small, dense LDL.

CONCLUSIONS

Atherogenic Lp abnormalities may be found in one-third of women with PCOS who have a normal lipid pattern. Future prospective studies are needed to test to which extent such atherogenic forms of dyslipidaemia may contribute to the increased cardiovascular risk in young women with PCOS.

Atherogenic lipoprotein phenotype and LDL size and subclasses in women with gestational diabetes

AIMS

Women with gestational diabetes are more likely to develop Type 2 diabetes and cardiovascular disease after pregnancy; however, the exact nature of the lipid alterations present is not clear. In Mediterranean women with gestational diabetes, we measured low-density lipoprotein (LDL) size and all seven subclasses, as well as the 'atherogenic-lipoprotein phenotype'[ALP, e.g. concomitant presence of elevated triglycerides, reduced high-density lipoprotein (HDL)-cholesterol and increased small, dense LDL].

METHODS

In 27 women with gestational diabetes and 23 healthy pregnant women matched for age, weeks of gestation and body mass index, we measured plasma lipids and LDL size and subclasses by gradient gel electrophoresis between 24 and 28 weeks of gestation.

RESULTS

Although no significant differences were found in the concentrations of any of the plasma lipids, compared with control subjects women with gestational diabetes had lower LDL size (P = 0.0007) due to reduced LDL-I (P = 0.0074) and increased LDL-IVA (P = 0.0146) and -IVB (P < 0.0001) subclasses. Correlation analysis revealed that fasting glucose, homeostasis model assessment and glycated haemoglobin were inversely correlated with LDL-I and positively with LDL-IVA and -IVB (all P < 0.05). ALP due to high HDL-cholesterol levels was not seen in either group, whereas elevated small, dense LDL were more common in women with gestational diabetes than control subjects (33% vs. 4%, P = 0.0107).

CONCLUSIONS

Increased levels of small, dense LDL are common in Mediterranean women with gestational diabetes. Whether these findings affect the atherogenic process and clinical end-points in these women remains to be determined by future prospective studies.

The increase of fatty acid-binding protein aP2 in overweight and obese children: interactions with dietary fat and impact on measures of subclinical inflammation

BACKGROUND

In adults, circulating aP2 may link obesity, inflammation and the metabolic syndrome, but there are few data in children. Experimental models support that dietary factors, particularly dietary fat, may be major determinants of phenotype.

OBJECTIVE

The aim of this study was to investigate, in normal, overweight and obese children, the relationships among aP2, the metabolic syndrome, inflammation and diet.

DESIGN

This was a cross-sectional study conducted in Northern Switzerland.

SUBJECTS

Subjects for this study were 6- to 14-year-old, prepubertal and early pubertal, normal weight, overweight and obese children (n=124).

MAIN OUTCOME MEASURES

Body mass index (BMI), body fat percent, waist-to-hip ratio, blood pressure, circulating aP2, fasting insulin, C-reactive protein (CRP), plasma lipids and dietary intakes of macro- and micronutrients were determined.

RESULTS

Circulating aP2 markedly increased with increasing central and total adiposity, and predicted measures of insulin resistance. Independent of BMI standard deviation scores and puberty, aP2 correlated with intake of the antioxidant vitamins A, C and E as well as circulating concentrations of CRP, leptin and low-density lipoprotein cholesterol. Children with lower aP2 concentrations consuming high-fat diets did not show an increase in fasting insulin or CRP, whereas those with higher aP2 concentrations showed marked increases in these measures with high intakes of fat or saturated fat.

CONCLUSIONS

Increased central and overall adiposity in children are associated with higher circulating aP2 concentrations. In children with high dietary intakes of total fat and saturated fat, but not those with low intakes, higher aP2 concentrations are associated with measures of insulin resistance and inflammation.

Has time come for new goals in human islet transplantation?

The enthusiasm regarding clinical islet transplantation has been dampened by the long-term results. Concerns about the associated risks of life-long immunosuppression and the striking imbalance between potential recipients and available donor pancreata warrant changes in some of the current goals. Islet transplantation will never be a cure of type 1 diabetes in the majority of patients with no secondary complications, but is a valid option for a limited number of patients with brittle diabetes waiting for an organ or after organ transplantation. Furthermore, insulin independence should not be the main goal of islet transplantation, but avoidance of severe hypoglycemia and good glycemic control, which can be achieved with a relatively small functional beta-cell mass. Therefore, initially one islet infusion is sufficient. Retransplantation at a later time point remains an option, if glucose control deteriorates. Efforts to improve islet transplantation should no longer focus on islet isolation and immunosuppression, but rather on the low posttransplant survival rate of islets caused by activation of the coagulation pathway and the limited oxygen delivery to the islets. Transplantation of smaller islets be it naturally small or size tailored reaggregated islets has the potential to facilitate these processes.

Unsuspected osteomyelitis is frequent in persistent diabetic foot ulcer and better diagnosed by MRI than by 18F-FDG PET or 99mTc-MOAB

AIM

Prevalence, optimal diagnostic approach and consequences of clinically unsuspected osteomyelitis in diabetic foot ulcers are unclear. Early diagnosis of this infection may be crucial to ensure correct management.

METHODS

We conducted a prospective study in 20 diabetic patients with a chronic foot ulcer (>8 weeks) without antibiotic pretreatment and without clinical signs for osteomyelitis to assess the prevalence of clinically unsuspected osteomyelitis and to compare the value of magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and 99mTc-labelled monoclonal antigranulocyte antibody scintigraphy (99mTc-MOAB). Those with suggestive scans underwent bone biopsy for histology (n = 7).

RESULTS

Osteomyelitis was confirmed by biopsy in seven of the 20 clinically unsuspected foot ulcers. Presence of osteomyelitis was not related to age, ulcer size, ulcer duration, duration of diabetes or HbA1c. C-reactive protein was slightly elevated in patients with osteomyelitis (35.1 +/- 16.0 mg L(-1) vs. 12.2 +/- 2.6 mg L(-1) in patients with and without osteomyelitis respectively; P = 0.07). MRI was positive in six of the seven patients with proven osteomyelitis, whereas 18F-FDG PET and 99mTc-MOAB were positive only in (the same) two patients. Of the seven patients with osteomyelitis, five had lower limb amputation and in one patient the ulcer was persisting after 24 months of follow-up. In contrast, of the 13 patients without detectable signs of osteomyelitis on imaging modalities only two had lower limb amputation and two persisting ulcers.

CONCLUSIONS

Clinically unsuspected osteomyelitis is frequent in persisting foot ulcers and is a high risk factor for adverse outcome. MRI appears superior to 18F-FDG PET and 99mTc-MOAB in detecting foot ulcer-associated osteomyelitis and might be the preferred imaging modality in patients with nonhealing diabetic foot ulcers.

Simultaneous islet-kidney vs pancreas-kidney transplantation in type 1 diabetes mellitus: a 5 year single centre follow-up

AIMS/HYPOTHESIS

The aim of this study was to compare the long-term outcomes--in terms of glucose control, renal function and procedure-related complications--of simultaneous islet-kidney (SIK) transplantation with those of simultaneous pancreas-kidney (SPK) transplantation in patients with type 1 diabetes mellitus.

METHODS

HbA1c, need for insulin, GFR and complication rate were compared between 13 recipients of SIK and 25 recipients of SPK transplants at the same institution. The mean follow-up was 41 months.

RESULTS

Two primary organ non-functions occurred in the SIK group. HbA1c did not differ at any time point during follow-up in the SIK group compared with the SPK group (mean during follow-up 6.3 vs 5.9%). Similarly, kidney function over time was not different between the two groups. A higher rate of insulin independence following SPK transplantation (after 1 year 96 vs 31% in the SIK group) was counterbalanced by a higher rate of serious adverse events (40% relaparotomies vs 0% in the SIK group).

CONCLUSIONS/INTERPRETATION

The endogenous insulin production achieved by islet transplantation, combined with optimal insulin therapy, was sufficient for maintaining near-normal glucose levels. In terms of glucose control, islet transplantation provides results comparable to those achieved with pancreas transplantation. However, SPK results in a higher rate of insulin independence, albeit at the cost of more surgical complications. These results have led to a new paradigm in islet transplantation at our institution, where the primary goal is not insulin independence, but good glucose control and avoidance of severe hypoglycaemia.

Assessment of Basal Insulin Requirement Using Fasting Tests in Insulin-treated Patients with Type 2 Diabetes Mellitus

AIMS

Characterizing the time course of the rise of blood glucose concentrations in the fasting state during the day and night in patients with type 2 diabetes.

METHODS

40 consecutive insulin-treated patients with type 2 diabetes underwent fasting tests on two different days with either no breakfast and lunch (fasting time of 20 hours) or no dinner (fasting time of 21 hours). Glucose-lowering medication was stopped prior to the test according to the half-life of the medication prescribed. At the start of the fasting tests, blood glucose concentrations were lowered to below 7 mmol/L using an insulin infusion.

RESULTS

26 men and 14 women were included in the study. Mean (+/-SD) age was 61+/-10 years, BMI 31+/-7 kg/m (2), and HbA1c 7.5+/-1%. Diabetes duration was 14+/-8 years and duration of insulin therapy had been prescribed for a mean of 6+/-6 years. During the daytime fast, plasma glucose concentrations rose by a mean of 0.8+/-1.6 mmol/L. During the nighttime fast, plasma glucose concentrations increased particularly after midnight, by 4.3+/-2.1 mmol/L, i.e. significantly more than during the daytime fast.

CONCLUSIONS

Fasting blood glucose concentrations in the majority of insulin-treated patients with type 2 diabetes increase markedly after midnight. No similar increase is observed during the day. Thus, for most patients with type 2 diabetes, an intermediate- or long-acting insulin injected at bedtime with a peak action six to eight hours after injection should be appropriate.

Urinary excretion of an intravenous 26Mg dose as an indicator of marginal magnesium deficiency in adults

BACKGROUND

Measurement of magnesium (Mg) status is problematic because tissue Mg deficiency can be present without low serum Mg concentrations.

OBJECTIVE

To evaluate a modified version of the Mg retention test using stable isotopes for the assessment of Mg status in general, and the detection of marginal Mg deficiency in particular.

DESIGN

A modified version of the Mg retention test using a small dose of (26)Mg was evaluated for assessment of Mg status in 22 healthy subjects. Muscle Mg concentration was used as reference for Mg status. A muscle biopsy was taken from the lateral portion of the quadriceps muscle from each subject. After 2 to 4 weeks, 11 mg of (26)Mg (as MgCl(2) in 14 ml water) were injected i.v. over a period of 10 min and all urine was collected for the following 24 h. Excretion of the isotopic label was expressed as percentage of the administered dose excreted in urine within 24 h.

RESULTS

Mean +/- s.d. Mg concentration in muscle was 3.85 +/- 0.17 mmol/100 g fat-free dried solids. Mean +/- s.d. excretion of the injected dose within 24 h was 7.9 +/- 2.1%. No correlation was found between muscle Mg concentration and excretion of the isotopic label (r (2 ) = 0.061, P = 0.27).

CONCLUSIONS

In this study, urinary excretion of an intravenous Mg tracer was not influenced by muscle Mg concentration and its usefulness for the detection of marginal Mg deficiency could therefore not be demonstrated.

SPONSORSHIP

Swiss Foundation for Nutrition Research and Swiss Federal Institute of Technology, Zurich, Switzerland.

Nitric oxide contributes to cytokine-induced apoptosis in pancreatic beta cells via potentiation of JNK activity and inhibition of Akt

AIMS/HYPOTHESIS

Pro-inflammatory cytokines cause beta cell secretory dysfunction and apoptosis--a process implicated in the pathogenesis of type 1 diabetes. Cytokines induce the expression of inducible nitric oxide (NO) synthase (iNOS) leading to NO production. NO contributes to cytokine-induced apoptosis, but the underlying mechanisms are unclear. The aim of this study was to investigate whether NO modulates signalling via mitogen-activated protein kinases (MAPKs) and Akt.

MATERIALS AND METHODS

MAPK activities in INS-1 cells and isolated islets were determined by immunoblotting and in vitro kinase assay. Apoptosis was determined by ELISA measurement of histone-DNA complexes present in cytoplasm.

RESULTS

Apoptosis in INS-1 cells induced by IL-1beta plus IFNgamma was dependent on NO production as demonstrated by the use of the NOS blocker NG-methyl-L-arginine. Accordingly, an NO donor (S-nitroso-N-acetyl-D, L-penicillamine, SNAP) dose-dependently caused apoptosis in INS-1 cells. SNAP activated c-Jun N-terminal kinase (JNK) and p38 MAPK, but suppressed the activity of extracellular signal-regulated kinase MAPK. In rat islets, NOS inhibition decreased JNK and p38 activities induced by a 6-h exposure to IL-1beta. Likewise, IL-1beta-induced JNK and p38 activities were lower in iNOS(-/-) mouse islets than in wild-type islets. In human islets, SNAP potentiated IL-1beta-induced JNK activation. The constitutive level of active, Ser473-phosphorylated Akt in INS-1 cells was suppressed by SNAP. IGF-I activated Akt and protected against SNAP-induced apoptosis. The anti-apoptotic effect of IGF-I was not associated with reduced JNK activation.

CONCLUSIONS/INTERPRETATION

We suggest that NO contributes to cytokine-induced apoptosis via potentiation of JNK activity and suppression of Akt.

The Metabolisable Hexoses D-Glucose and D-Mannose Enhance the Expression of IRS-2 but not of IRS-1 in Pancreatic β-Cells

D-glucose regulates maintenance and function of pancreatic beta-cells. Several studies have shown that IRS-2, but not IRS-1, is necessary to maintain and sufficient to expand functional beta-cell mass. We therefore analyzed the expression of IRS-2 and IRS-1 in beta-cells after culture in the presence of various concentrations of D-glucose and other metabolisable or non-metabolisable hexoses. D-glucose increased Irs-2 transcription and IRS-2 accumulation in a dose-dependent manner (1.6 to 25 mmol/l), with a 3-fold increased plateau after 10 h. In contrast, the expression of IRS-1 remained unaffected. D-glucose also induced phosphorylation of IRS-2 while non-metabolisable hexoses did neither affect expression nor phosphorylation. D-glucose-mediated elevation and phosphorylation of IRS-2 were independent of autocrine insulin action although insulin itself could transiently and slightly enhance IRS-2 expression.

Inseltransplantation bei Typ 1 Diabetes mellitus

Der Traum, die durch einen Autoimmunpozess zerstörten Inseln des Pankreas (genauer der Betazellen) ersetzen zu können, rückte im Juli 2000 durch eine bahnbrechende Studie über Inseltransplantation einen beträchtlichen Schritt näher. In Edmonton konnte gezeigt werden, dass dank Transplantation von Inseln bei nicht urämischen Patienten mit Typ 1 Diabetes das Erreichen einer vollkommenen Insulinunabhängigkeit zur Regel wird. Der Erfolg, der inzwischen an vielen anderen Orten der Welt repliziert werden konnte, ist dadurch zu erklären, dass die Inseln von mehreren Spendern und eine steroidfreie Immunsuppression verwendet wurde. Dank dieses «Edmonton Protokolls» konnte die Insulinunabhängigkeit ein Jahr nach Transplantation auf 80% gesteigert werden. Es wurde aber auch festgestellt, dass beim längeren Follow-up dieser Prozentsatz deutlich absinkt. Aus diesem Grunde müsste von Zeit zu Zeit eine Inseltransplantation wiederholt werden, um die Insulinunabhängigkeit aufrecht erhalten zu können. Wegen dem ausgeprägten Organmangel kam es zu einem Paradigmenwechsel: Das Hauptziel, welches mit der Inseltransplantation verfolgt wird, ist nicht mehr unbedingt eine Insulinunabhängigkeit, sondern eine gute Blutzuckerkontrolle unter Vermeidung von schweren Hypoglykämien. Dieses Ziel kann bei 80–90% aller Patienten, welche eine Inseltransplantation erhielten, erfüllt werden, auch wenn geringe Dosen von Insulin injiziert werden müssen. Die lebenslang notwendige Immunsuppression hingegen limitiert diese praktisch komplikationslose Therapieform auf Patienten, welche eine andere Organtransplantation benötigen oder trotz optimierter Diabetesbehandlung lebensbedrohliche Hypoglykämien erleiden. Die häufigste Indikation bei uns sind Patienten mit einer chronischen dialysepflichtigen Niereninsuffizienz und einem Typ 1 Diabetes mellitus. Diese Patienten sollten auf die Möglichkeit einer kombinierten Insel-Nierentransplantation oder Pankreas-Nierentransplantation aufmerksam gemacht werden. Die Wahl, ob eine Insel- oder Pankreastransplantation in Frage kommt, hängt in allererster Linie vom Alter und vom Ausmaß der Begleiterkrankungen, vor allem kardiovaskulärer Art, ab, die wiederum mit Diabetesdauer, Alter und Qualität der Blutzuckereinstellung zusammenhängen.

Overexpression of IRS2 in isolated pancreatic islets causes proliferation and protects human beta-cells from hyperglycemia-induced apoptosis

Studies in vivo indicate that IRS2 plays an important role in maintaining functional beta-cell mass. To investigate if IRS2 autonomously affects beta-cells, we have studied proliferation, apoptosis, and beta-cell function in isolated rat and human islets after overexpression of IRS2 or IRS1. We found that beta-cell proliferation was significantly increased in rat islets overexpressing IRS2 while IRS1 was less effective. Moreover, proliferation of a beta-cell line, INS-1, was decreased after repression of Irs2 expression using RNA oligonucleotides. Overexpression of IRS2 in human islets significantly decreased apoptosis of beta-cells, induced by 33.3 mM D-glucose. However, IRS2 did not protect cultured rat islets against apoptosis in the presence of 0.5 mM palmitic acid. Overexpression of IRS2 in isolated rat islets significantly increased basal and D-glucose-stimulated insulin secretion as determined in perifusion experiments. Therefore, IRS2 is sufficient to induce proliferation in rat islets and to protect human beta-cells from D-glucose-induced apoptosis. In addition, IRS2 can improve beta-cell function. Our results indicate that IRS2 acts autonomously in beta-cells in maintenance and expansion of functional beta-cell mass in vivo.

Hypoglycemia in response to glucose and glucagon in insulinoma patients with a negative prolonged fast: functional and morphological properties

A negative 72-h fast is usually considered to preclude the diagnosis of insulinoma. The aim of this study was to describe the functional and morphological properties of two exceptional patients with an insulinoma who had exhibited pre-operatively a negative 72-h fast. Despite the ability of tumor cells to turn off insulin secretion in response to low plasma glucose during 72 h of fasting, hyperinsulinemic hypoglycemia occurred in both patients in response to stimulation by classical secretagogues. Pre-operatively, both patients underwent oral and iv glucose challenge tests and iv glucagon stimulation test. Insulin secretion was rapidly stimulated by these secretagogues to an exaggerated extent and thereby caused hypoglycemia due to an insulin mass effect. In contrast to the common functional features during suppression and stimulation tests, the tumors differed widely with regard to insulin and proinsulin response to calcium during ASVS tests and morphological properties. In patient 1, the immunohistochemical proinsulin distribution pattern resembled that of normal beta-cells, i.e. the staining was restricted to the perinuclear area; insulin and proinsulin were not stimulated by calcium during the ASVS test. In patient 2, the proinsulin staining pattern was abnormal, i.e. proinsulin was also found in the periphery of tumor cells; insulin and proinsulin were stimulated by calcium. We conclude that normal or exaggerated rather than defective glucose sensing may explain hypoglycemia in these exceptional insulinoma patients. Different functional characteristics of these tumors can be correlated with distinct morphological properties.

Glucose control is not improved by accelerating gastric emptying in patients with type 1 diabetes mellitus and gastroparesis. a pilot study with cisapride as a model drug

The present pilot study investigated whether acceleration of gastric emptying in patients with type 1 diabetes and delayed gastric emptying (a possible cause of poorly controlled diabetes) improves long-term glucose control. Eight outpatients with diabetes (age 28-63 years, mean diabetes duration 24.6+/-6.0 years) and delayed gastric emptying of radio-opaque markers were randomised and treated, for three months each, with a prokinetic drug (cisapride 20 mg twice daily) and placebo. Mean capillary glucose, glucose variability (M-values, MAGE), fructosamine, and HbA1c were assessed. Gastric emptying of a solid standard meal was measured by scintigraphy after each treatment period. Chronic administration of a prokinetic drug resulted in improved solid gastric emptying (percentage residual) at 120 min (p=0.025). The percentage residual was 43.6+/-9.6 % during prokinetic treatment and 59.7+/-9.9 % during placebo (standard error of paired differences 5.7 %). The mean gastric emptying time (t/2) of solids was 88 min during prokinetic treatment compared to 113 min in the placebo arm (SE of paired differences 14 min; p=0.09). Mean blood glucose values (9.0+/-3.8 vs. 8.8+/-3.7 mmol/l), daily glucose variability (MAGE 6.8+/-1.3 vs. 6.3+/-1.6 mmol/l; M-value 15.2+/-2.5 vs. 13.9+/-4.5), and HbA1c at 3 months (7.8+/-1.1 % vs. 7.6+/-1.0 %) were not statistically different between prokinetic drug and placebo treatment. Similarly, the frequency of hypoglycaemic episodes (< or = 3 mmol/l) was not different in both groups (78 vs. 68). Our pilot study showed that long-term acceleration of gastric emptying had no effect on overall glycaemic control, the magnitude of glucose excursions, and hypoglycaemic episodes in patients with diabetic gastroparesis. We do not recommend, therefore, acceleration of gastric emptying as treatment strategy for "brittle diabetes" in patients with type 1 diabetes.

A plasma glucose concentration below 2.5 mmol L-1 is not an appropriate criterion to end the 72-h fast

CONTEXT

The classical end-point to terminate the 72-h fast in a patient evaluated for a hypoglycaemic disorder is the occurrence of hypoglycaemic symptoms in association with a low plasma glucose level. However, neither the symptoms nor the plasma glucose level have been exactly defined.

OBJECTIVE

To determine whether a useful cut-off plasma glucose concentration as criterion to end the prolonged fast in the absence of neuroglycopenic symptoms can be defined.

DESIGN

Single centre case-control study.

SETTING

Tertiary referral hospital in Switzerland.

SUBJECTS

The 72-h fast was prospectively performed in 23 consecutive patients (17 women and six men) following a standardized protocol between July 1999 and January 2002. All patients were referred to our clinic for evaluation of suspected hypoglycaemia. The criterion to end the fast before 72 h was defined by the occurrence of symptoms or signs typical for neuroglycopenia irrespective of plasma glucose levels.

MAIN OUTCOME MEASURE

Insulin levels and insulin to plasma glucose ratios in insulinoma patients and in individuals without insulin-secreting tumours at termination of the fast and at plasma glucose levels </=2.5 mmol L-1, prior to the occurrence of neuroglycopenic symptoms.

RESULTS

In seven patients, the fast was terminated before 72 h because they developed neuroglyco-penic symptoms. Insulin-secreting tumours were found and successfully removed in these seven patients. Sixteen individuals developed no neuroglycopenic symptoms throughout the 72-h fast and an insulin-secreting tumour could be excluded in these 16 patients. Five of these 16 individuals had plasma glucose levels </=2.5 mmol L-1 during the 72-h fast. Insulin levels and insulin to glucose ratios in insulinoma patients and healthy individuals overlapped during as well as at termination of the fast. Prior to the occurrence of neuroglycopenic symptoms and at venous plasma glucose </=2.5 mmol L-1, insulin to plasma glucose ratios dropped in insulinoma patients to values within the normal range on several occasions.

CONCLUSIONS

Terminating the fast at plasma glucose levels </=2.5 mmol L-1 does not allow confirmation or exclusion of an insulin-secreting tumour. Thus, the occurrence of symptoms or signs typical for neuroglycopenia is the prerequisite criterion to end the fast before 72 h.

[General insulin therapy practice in type 2 diabetes mellitus]

In most patients with Type 2 Diabetes, the primary treatment goal is near-normoglycemia. If diet, physical activity, and oral hypoglycemic agents fail to achieve the individual treatment goal, insulin therapy must be considered. Insulin therapy in patients with Type 2 Diabetes is safe, highly efficient and should be initiated not too late. We recommend to perform the insulin therapy in Type 2 Diabetics individually upon the patients characteristics, no general recommendation can be given. Possible approaches to start an insulin therapy in general practice are discussed. Insulin therapy may be initiated as bedtime insulin (depot insulin at bedtime) in combination with oral agents. In patients who fail to achieve good glycemic control with this combination therapy, mealtime insulin (short-acting insulin before the meals) may be introduced instead of the oral agents (multiple injection regimen). Bedtime insulin may be discontinued when fasting glucose concentrations remain in the desired range and no rise of glucose concentrations occurs during the night. The two-insulin-injection regimen with mixed insulin formulations may be initiated in patients with Type 2 Diabetes when a multiple injection regimen is not feasible. The two-insulin-injection should not be considered as the primary insulin strategy in patients with Type 2 Diabetes.

[Management of cardiovascular risk factors in type 2 diabetes mellitus]

Cardiovascular disease is by far the major cause of morbidity and mortality in subjects with diabetes mellitus type 2. The risk of cardiovascular disease in persons with type 2 diabetes is greater for any given risk factor, alone or in combination, than it is in persons without diabetes. Independent risk factors for cardiovascular disease in type 2 diabetes are hyperglycemia, hypertension, dyslipidemia and smoking. Subjects with diabetes mellitus type 2 benefit from cardiovascular risk factor modification, either as a primary or secondary intervention, as much as or more than those without diabetes. Risk factor modification includes behavioral modification to affect regular physical activity, healthy diet, weight loss, and smoking cessation. In addition, an optimal glycemic control with HbA1c < 7% is crucial and, aggressive management of hypertension (< 130/80 mmHg) and dyslipidemia are particularly important. Finally, aspirin (100 mg/d) is standard in secondary prophylaxis of cardiovascular events and should strongly be considered in primary prophylaxis if subjects have more than 1 concomitant cardiovascular risk factors.

[Practical management of diabetic foot]

Prevention and the correct treatment of the diabetic foot have important social and economic consequences. Risk stratification is essential for choosing the appropriate treatment strategy. History and careful clinical examination identify the risk in each individual patient with diabetes. Peripheral neuropathy (PNP), foot deformation, peripheral arterial disease (PAD) and a history of previous ulcer or amputation are the most important risk factors. PAD must be diagnosed and treated by percutan transluminal angioplasty or bypass surgery where necessary. Primary foot deformation or secondary due to PNP require shoe modifications. Good metabolic control of diabetes and treatment of other cardiovascular risk factors (dyslipidemia, hypertension) delay or prevent the development of PNP and PAD. Therefore an early multidisciplinary approach is essential for each patient with diabetes and foot problems. In the presence of a foot ulcer, it's important to diagnose osteomyelitis by clinical or radiological examination. The choice and duration of antibiotic treatment and surgical intervention depends on the localisation and extension of infection around the ulcer and the presence of osteomyelitis. In case of limb threatening infection, the patient should be referred to a specialized treatment facility immediately.

[The pathogenesis of type 2 diabetes--new aspects and clinical consequences]

Type 2 diabetes mellitus manifests itself in individuals who lose the ability to produce sufficient quantities of insulin to maintain normoglycemia in the face of insulin resistance. The ability to secrete adequate amounts of insulin depends on beta-cell function and mass. The endocrine pancreas has a remarkable capacity to adapt to conditions of increased insulin demand and only a minority of individuals fail to adapt and become diabetic with time. Secondary events that further reduce the function of beta-cells in type 2 diabetes mellitus are the so-called beta-cell gluco- and lipotoxicity: chronic stimulation of islets by high glucose and free fatty acid levels results in the reduction of insulin secretion. Part of these effects are reversible once these metabolites are normalized and the beta-cell re-exposed to a physiologic environment. The essential role of the beta-cell failure in type 2 diabetes is reminiscent to the pathophysiology of type 1 diabetes. The possible link between both diseases and the therapeutic implications are discussed.

Dietary magnesium intake in type 2 diabetes

BACKGROUND

Magnesium deficiency is common in type 2 diabetes and may have a negative impact on glucose homeostasis and insulin resistance, as well as on the evolution of complications such as retinopathy, thrombosis and hypertension.

OBJECTIVE

To assess the dietary magnesium intake of patients with type 2 diabetes in Zurich, Switzerland and to compare the magnesium intake of diabetic and non-diabetic subjects.

DESIGN

The magnesium intake of 97 randomly selected patients with type 2 diabetes and 100 healthy, non-diabetic controls matched for age and sex was estimated using a diet history method. During winter and summer periods, mean daily magnesium intakes were calculated from detailed information given by the test subjects about their eating habits over the previous 2 months. The calculations were performed using EBIS, a computer program based on a German nutrient data base (BLS 2.3), with food items specific to Switzerland added or directly analysed when necessary.

RESULTS

The mean+/-s.d. daily magnesium intake of the male diabetic and male control subjects was 423.2+/-103.1 and 421.1+/-111.0 mg, respectively. The mean daily magnesium intake of the female diabetic and female control subjects was 419.1+/-109.7 and 383.5+/-109.7 mg, respectively. There were no significant differences in daily magnesium intake between the diabetic and the non-diabetic subjects and mean intakes in both groups exceeded Swiss recommended dietary intakes.

CONCLUSIONS

Dietary intake of magnesium appears sufficient in Swiss adults with type 2 diabetes and is unlikely to contribute to the aetiology of magnesium deficiency.

SPONSORSHIP

The Swiss Federal Institute of Technology, Zurich, Switzerland.

Glucose and palmitic acid induce degeneration of myofibrils and modulate apoptosis in rat adult cardiomyocytes

Several studies support the concept of a diabetic cardiomyopathy in the absence of discernible coronary artery disease, although its mechanism remains poorly understood. We investigated the role of glucose and palmitic acid on cardiomyocyte apoptosis and on the organization of the contractile apparatus. Exposure of adult rat cardiomyocytes for 18 h to palmitic acid (0.25 and 0.5 mmol/l) resulted in a significant increase of apoptotic cells, whereas increasing glucose concentration to 33.3 mmol/l for up to 8 days had no influence on the apoptosis rate. However, both palmitic acid and elevated glucose concentration alone or in combination had a dramatic destructive effect on the myofibrillar apparatus. The membrane-permeable C2-ceramide but not the metabolically inactive C2-dihydroceramide enhanced apoptosis of cardiomyocytes by 50%, accompanied by detrimental effects on the myofibrils. The palmitic acid-induced effects were impaired by fumonisin B1, an inhibitor of ceramide synthase. Sphingomyelinase, which activates the catabolic pathway of ceramide by metabolizing sphingomyeline to ceramide, did not adversely affect cardiomyocytes. Palmitic acid-induced apoptosis was accompanied by release of cytochrome c from the mitochondria. Aminoguanidine did not prevent glucose-induced myofibrillar degeneration, suggesting that formation of nitric oxide and/or advanced glycation end products play no major role. Taken together, these results suggest that in adult rat cardiac cells, palmitic acid induces apoptosis via de novo ceramide formation and activation of the apoptotic mitochondrial pathway. Conversely, glucose has no influence on adult cardiomyocyte apoptosis. However, both cell nutrients promote degeneration of myofibrils. Thus, gluco- and lipotoxicity may play a central role in the development of diabetic cardiomyopathy.

Assessment of selective arterial calcium stimulation and hepatic venous sampling to localize insulin-secreting tumours

OBJECTIVE

Non-invasive localization modalities such as ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) often fail to localize insulinomas smaller than 2 cm in diameter. Recent studies have shown that the selective arterial stimulation and hepatic venous sampling (ASVS) technique using intra-arterial calcium as the insulin secretagogue facilitates the regionalization of such occult insulinomas. This study assesses the sensitivity of ASVS in localizing insulin-secreting tumours.

SUBJECTS AND METHODS

Eleven consecutive patients (8 women), aged 29-82 years, were studied over the past 4 years at our hospital. Hyperinsulinaemic hypoglycaemia due to an insulin-secreting tumour was proven in all patients. Calcium gluconate (0.025 mEq/kg body weight) was injected directly into the arteries supplying the pancreas and the liver. Insulin levels were measured in samples taken from the right hepatic vein before and 30, 60 and 120 s after each injection. The ASVS technique was performed in all 11 patients; the results were compared with the surgical findings in 10 patients and the autopsy findings in 1 case. The ASVS results were also compared with the findings of other, previously performed imaging modalities.

RESULTS

ASVS correctly localized 4 insulin-secreting tumours to the head, 3 to the body, 1 to the tail, 2 to the tail or body of the pancreas and 1 to the liver. Thus, the sensitivity was 100% (11/11) whereas other localization techniques were less sensitive: 7/11 tumours were detected by angiography, 4/8 by endosonography, 3/8 by CT and 1/6 by MRI. Insulinomas (confirmed by histological examination), sized 4-25 mm, were found in 10 patients. All were cured by selective surgery and remained free of hypoglycaemia over the next 1-4 years of follow-up. An insulin-secreting neuroendocrine tumour in the liver was documented in 1 case at autopsy.

CONCLUSIONS

Arterial stimulation and hepatic venous sampling is a very sensitive technique for preoperative localization of insulin-producing tumours. It can help to plan minimally invasive surgery and to select an appropriate strategy for patients suffering from malignant tumours in others.

Clinical and technical evaluation of a new self-monitoring blood glucose meter: assessment of analytical and user error

Our study aimed to validate (against the standards of the American Diabetes Association and the International Organization for Standardization) the analytical and clinical accuracy of the new MediSense Precision Plus Electrodes on the QID system when compared with a reference method using the Abbott Vision glucose analyzer. Previous studies have shown that the overall accuracy of the device also depends on the proficiency of the operator, so we also assessed the 'ease of use' of the MediSense system, by comparing the results obtained by the patient and health care professional. Accuracy of the self-monitored blood glucose measurements was evaluated over a wide range of glucose readings (2.6-20.0 mmol/l). Between-run CVs (using the manufacturer's quality control material) were found to be 7% at 2.7 mmol/l and 4.8% at 15.5 mmol/l (n=380). We used the error-grid analysis with target range blood glucose, then separated the data into different subsets. We found that 100% of all measurements were in the clinically acceptable zones of A and B. All measured values of the MediSense QID system complied with the requirements for 'blood glucose monitoring meters', as proposed by the International Organization for Standardization. The rating of the patient questionnaire showed a good to very good overall rating and acceptance with a short instruction time. The results indicate that that the MediSense QID/Precision Plus Electrodes is a reliable and easy to use device, which can be recommended for the majority of patients with diabetes mellitus.

Glucose induces beta-cell apoptosis via upregulation of the Fas receptor in human islets

In autoimmune type 1 diabetes, Fas-to-Fas-ligand (FasL) interaction may represent one of the essential pro-apoptotic pathways leading to a loss of pancreatic beta-cells. In the advanced stages of type 2 diabetes, a decline in beta-cell mass is also observed, but its mechanism is not known. Human islets normally express FasL but not the Fas receptor. We observed upregulation of Fas in beta-cells of type 2 diabetic patients relative to nondiabetic control subjects. In vitro exposure of islets from nondiabetic organ donors to high glucose levels induced Fas expression, caspase-8 and -3 activation, and beta-cell apoptosis. The effect of glucose was blocked by an antagonistic anti-Fas antibody, indicating that glucose-induced apoptosis is due to interaction between the constitutively expressed FasL and the upregulated Fas. These results support a new role for glucose in regulating Fas expression in human beta-cells. Upregulation of the Fas receptor by elevated glucose levels may contribute to beta-cell destruction by the constitutively expressed FasL independent of an autoimmune reaction, thus providing a link between type 1 and type 2 diabetes.

Diminished insulin secretory response to glucose but normal insulin and glucagon secretory responses to arginine in a family with maternally inherited diabetes and deafness caused by mitochondrial tRNA(LEU(UUR)) gene mutation

OBJECTIVE

The effects of glucose, arginine, and glucagon on beta-cell function as well as alpha-cell response to arginine were studied in a family with mitochondrial diabetes.

RESEARCH DESIGN AND METHODS

The function of alpha- and beta-cells was assessed in all five siblings carrying the mitochondrial tRNA Leu(UUR) gene mutation at position 3243 and compared with six sex-, age-, and weight-matched control subjects. Insulin and C-peptide responses were evaluated by intravenous glucagon application, intravenous arginine stimulation test, and intravenous glucose tolerance test. Glucagon secretion was assessed during the arginine stimulation test.

RESULTS

The glucose disappearance constant (K(g)) value (mean +/- SEM 0.61 +/- 0.04 vs. 1.1 +/- 0.04, P = 0.0002) as well as the acute insulin response to glucose (area under the curve [AUC] 0-10 min, 77.7 +/- 50.7 vs. 1,352.3 +/- 191.5 pmol/l, P = 0.0004) were decreased in all patients. Similarly, glucagon-stimulated C-peptide response was also impaired (728 +/- 111.4 vs. 1,526.7 +/- 157.7 pmol/l, P = 0.005), whereas the insulin response to arginine (AUC) was normal (1,346.9 +/- 710.8 vs. 1,083.2 +/- 132.5 pmol/l, P = 0.699). Acute glucagon response to arginine (AUC) was normal but tended to be higher in the patients than in the control subjects (181.7 +/- 47.5 vs. 90.0 +/- 21.1 pmol/l, P = 0.099).

CONCLUSIONS

This study shows impaired insulin and C-peptide secretion in response to a glucose challenge and to glucagon stimulation in diabetic patients with mitochondrial tRNA Leu(UUR) gene mutation, although insulin and glucagon secretory responses to arginine were normal.

10 Swiss kindreds with multiple endocrine neoplasia type 1: assessment of screening methods

PRINCIPLES

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disease characterised by the combined occurrence of tumours of the parathyroid glands, the enteropancreatic neuroendocrine system and the anterior pituitary gland. The genetic defect has been mapped to the long arm of chromosome 11q13, and the MEN1-gene was recently identified by positional cloning. Genetic screening for MEN1 germline mutations allows the identification of gene carriers in affected kindreds. Biochemical and radiological screening for MEN1 tumours allows an earlier diagnosis and treatment, and, thus may reduce morbidity and mortality. Since there is no consensus about the frequency and the extent of the necessary screening investigations, evaluation of proposed screening programs is of importance.

METHODS

The aims of our study were to identify the MEN1-gene mutations and to detect the gene-carriers in 10 Swiss MEN1 families, as well as to assess biochemical and radiological screening methods. The study included 45 members from 10 MEN1 families.

RESULTS

Every family had a different type of MEN1-gene mutation. Thirty out of 45 family members were gene mutation carriers. Twenty-two MEN1-gene carriers had typical MEN1 tumours: parathyroid, enteropancreatic and pituitary tumours were found in 21, 14 and 1 patients, respectively. Applying a defined screening program the following manifestations in asymptomatic MEN1-gene carriers were detected: 9 primary hyperparathyroidism, 3 nonfunctioning pancreatic tumours, 1 gastrinoma, 1 nonfunctioning microadenoma of the pituitary and 1 macronodular adrenal hyperplasia.

CONCLUSIONS

The genetic screening facilitates the identification of individuals who carry MEN1-gene mutations, and allows one to exclude non-mutant gene carriers from further investigations. The prospective biochemical and radiological screening of gene mutation carriers allows the earlier detection of MEN1-associated tumours. Therefore, it might be expected that morbidity and mortality of the MEN1 could be reduced.

10 Swiss kindreds with multiple endocrine neoplasia type 1: assessment of screening methods

PRINCIPLES

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disease characterised by the combined occurrence of tumours of the parathyroid glands, the enteropancreatic neuroendocrine system and the anterior pituitary gland. The genetic defect has been mapped to the long arm of chromosome 11q13, and the MEN1-gene was recently identified by positional cloning. Genetic screening for MEN1 germline mutations allows the identification of gene carriers in affected kindreds. Biochemical and radiological screening for MEN1 tumours allows an earlier diagnosis and treatment, and, thus may reduce morbidity and mortality. Since there is no consensus about the frequency and the extent of the necessary screening investigations, evaluation of proposed screening programs is of importance.

METHODS

The aims of our study were to identify the MEN1-gene mutations and to detect the gene-carriers in 10 Swiss MEN1 families, as well as to assess biochemical and radiological screening methods. The study included 45 members from 10 MEN1 families.

RESULTS

Every family had a different type of MEN1-gene mutation. Thirty out of 45 family members were gene mutation carriers. Twenty-two MEN1-gene carriers had typical MEN1 tumours: parathyroid, enteropancreatic and pituitary tumours were found in 21, 14 and 1 patients, respectively. Applying a defined screening program the following manifestations in asymptomatic MEN1-gene carriers were detected: 9 primary hyperparathyroidism, 3 nonfunctioning pancreatic tumours, 1 gastrinoma, 1 nonfunctioning microadenoma of the pituitary and 1 macronodular adrenal hyperplasia.

CONCLUSIONS

The genetic screening facilitates the identification of individuals who carry MEN1-gene mutations, and allows one to exclude non-mutant gene carriers from further investigations. The prospective biochemical and radiological screening of gene mutation carriers allows the earlier detection of MEN1-associated tumours. Therefore, it might be expected that morbidity and mortality of the MEN1 could be reduced.

Economic and clinical impact of alternative disease management strategies for secondary prevention in type 2 diabetes in the Swiss setting

PRINCIPLES

Different intervention strategies for the optimisation of disease management of diabetes exist and have been shown to increase the proportion of patients receiving screening and examinations and to improve risk factors such as HbA1c, lipids, and blood pressure. Thus, in the long-term, a decrease in diabetic complications and the associated costs could be expected. To address this question, the current analysis used a published diabetes simulation model to analyse the long-term clinical and economic implications of implementing various interventions in the Swiss setting.

METHODS

Based on data from the literature, the short-term effects on clinical variables of multifactorial interventions, including screening for nephropathy and retinopathy, educational programmes and control of cardiovascular risk profile were assessed, and a cost-effectiveness analysis in comparison to standard care was performed. Life expectancy (LE) and total lifetime costs (TC) from the perspective of the health insurance payer were calculated using a long-term Markov simulation model.

RESULTS

The multifactorial intervention led to an improvement in undiscounted LE of 0.56 years (LE = 10.73 and 11.29 years for standard care and multifactorial intervention respectively), and a reduction in 3%-discounted TC of CHF 7313 (10.7%) per patient compared to current standard practice. Extrapolation to the whole Swiss type 2 diabetes population (285,000) showed yearly cost savings of CHF 194 million from the multifactorial intervention.

CONCLUSIONS

The implementation of multifactorial interventions, including improved control of cardiovascular risk factors, combined with early diagnosis and treatment of diabetic complications, could be both cost- and life-saving in the Swiss setting.

Economic and clinical impact of alternative disease management strategies for secondary prevention in type 2 diabetes in the Swiss setting

PRINCIPLES

Different intervention strategies for the optimisation of disease management of diabetes exist and have been shown to increase the proportion of patients receiving screening and examinations and to improve risk factors such as HbA1c, lipids, and blood pressure. Thus, in the long-term, a decrease in diabetic complications and the associated costs could be expected. To address this question, the current analysis used a published diabetes simulation model to analyse the long-term clinical and economic implications of implementing various interventions in the Swiss setting.

METHODS

Based on data from the literature, the short-term effects on clinical variables of multifactorial interventions, including screening for nephropathy and retinopathy, educational programmes and control of cardiovascular risk profile were assessed, and a cost-effectiveness analysis in comparison to standard care was performed. Life expectancy (LE) and total lifetime costs (TC) from the perspective of the health insurance payer were calculated using a long-term Markov simulation model.

RESULTS

The multifactorial intervention led to an improvement in undiscounted LE of 0.56 years (LE = 10.73 and 11.29 years for standard care and multifactorial intervention respectively), and a reduction in 3%-discounted TC of CHF 7313 (10.7%) per patient compared to current standard practice. Extrapolation to the whole Swiss type 2 diabetes population (285,000) showed yearly cost savings of CHF 194 million from the multifactorial intervention.

CONCLUSIONS

The implementation of multifactorial interventions, including improved control of cardiovascular risk factors, combined with early diagnosis and treatment of diabetic complications, could be both cost- and life-saving in the Swiss setting.

Alterations of lipolytic enzymes and high-density lipoprotein subfractions induced by physical activity in type 2 diabetes mellitus

OBJECTIVE

This study investigates the effects of regular moderate physical activity on lipolytic enzymes and plasma lipid concentration, particularly high-density lipoprotein cholesterol (HDL-C) subfractions, in patients with type 2 diabetes mellitus.

DESIGN

Ten patients participated in a 3-month exercise programme without any changes in current medical therapy. The control group consisted of six patients who were matched with regard to sex, age, diabetes duration and diabetes therapy.

RESULTS

Mean (+/- SE) physical activity in the intervention group increased from 70 +/- 21 to 220 +/- 28 min per week, which resulted in an increase in total HDL-C from 1.04 +/- 0.07 to 1.28 +/- 0.12 (P < 0.001). The HDL3-C subfraction increased from 0.71 +/- 0.08 to 0.86 +/- 0.08 mM (P = 0.01) with no significant changes in the HDL2-C subfraction (0.33 +/- 0.04 vs. 0.42 +/- 0.05). These changes were paralleled by an 85% increase in hepatic lipase (HL) activity, from 25.7 +/- 5.1 to 47.4 +/- 4.9 micromol x mL(-1) x h(-1) (P < 0.001) and a 45% increase in lipoprotein lipase (LPL) activity, from 16.8 +/- 3.0-24.3 +/- 2.7 micromol x mL(-1) x h(-1) (P = 0.01). Lecithin-cholesterol acyl-transferase (LCAT) activity increased by 32%, from 156 +/- 26 to 206 +/- 32 nmol x mL(-1) x h(-1) (P < 0.001). In the control group there were no significant changes in any of the variables assessed.

CONCLUSIONS

Regular moderate physical activity in patients with type 2 diabetes led to an overall increase in HL, LPL, and LCAT. HL showed a more pronounced increase than LPL and LCAT. The changes in lipolytic and transferase enzyme pattern resulted in a significant increase of plasma HDL-C, mainly of the HDL3-C subfraction.

Distinct effects of saturated and monounsaturated fatty acids on beta-cell turnover and function

Glucotoxicity and lipotoxicity contribute to the impaired beta-cell function observed in type 2 diabetes. Here we examine the effect of saturated and unsaturated fatty acids at different glucose concentrations on beta-cell proliferation and apoptosis. Adult rat pancreatic islets were cultured onto plates coated with extracellular matrix derived from bovine corneal endothelial cells. Exposure of islets to saturated fatty acid (0.5 mmol/l palmitic acid) in medium containing 5.5, 11.1, or 33.3 mmol/l glucose for 4 days resulted in a five- to ninefold increase of beta-cell DNA fragmentation. In contrast, monounsaturated palmitoleic acid alone (0.5 mmol/l) or in combination with palmitic acid (0.25 or 0.5 mmol/l each) did not affect DNA fragmentation. Increasing concentrations of glucose promoted beta-cell proliferation that was dramatically reduced by palmitic acid. Palmitoleic acid enhanced the proliferation activity in medium containing 5.5 mmol/l glucose but had no additional effect at higher glucose concentrations (11.1 and 33.3 mmol/l). The cell-permeable ceramide analog C2-ceramide mimicked both the palmitic acid-induced beta-cell apoptosis and decrease in proliferation. Moreover, the ceramide synthetase inhibitor fumonisin B1 blocked the deleterious effects of palmitic acid on beta-cell viability. Additionally, palmitic acid but not palmitoleic acid decreased the expression of the mitochondrial adenine nucleotide translocator and induced release of cytochrome c from the mitochondria into the cytosol. Finally, palmitoleic acid improved beta-cell-secretory function that was reduced by palmitic acid. Taken together, these results suggest that the lipotoxic effect of the saturated palmitic acid involves an increased apoptosis rate coupled with reduced proliferation capacity of beta-cells and impaired insulin secretion. The deleterious effect of palmitate on beta-cell turnover is mediated via formation of ceramide and activation of the apoptotic mitochondrial pathway. In contrast, the monounsaturated palmitoleic acid does not affect beta-cell apoptosis, yet it promotes beta-cell proliferation at low glucose concentrations, counteracting the negative effects of palmitic acid as well as improving beta-cell function.

Applying some UK Prospective Diabetes Study results to Switzerland: the cost-effectiveness of intensive glycaemic control with metformin versus conventional control in overweight patients with type-2 diabetes

OBJECTIVE

The results of the metformin substudy of the United Kingdom Prospective Diabetes Study (UKPDS) were applied through modelling techniques to the Swiss setting, allowing a cost-effectiveness analysis of the management of overweight type-2 diabetes patients with either conventional glycaemic control or intensive control with metformin from the Swiss third-party payer perspective.

METHODS

Occurrence of diabetes-related complications was simulated using a Markov model. Probabilities for complications were taken from the UKPDS, and costs were retrieved from published sources. Total direct costs (costs of diabetes therapy plus costs of treating complications) and survival over an 11-year period were determined for cohorts randomised to either conventional glycaemic control or intensive control with metformin. Changes in life expectancy were calculated for conventional versus intensive control with metformin. Extensive sensitivity analysis was performed.

RESULTS

Mean costs per patient over the 11-year follow-up period (discounted at 5% per annum) were CHF 10,877 and CHF 9950 for patients randomised to either conventional control or intensive control with metformin respectively. Intensive control with metformin led to improved survival (0.43 life-years gained per patient) over the 11-year-period. Outcomes were most sensitive to variations in the acquisition costs of metformin. Changes in the event rates and costs related to myocardial infarction, renal failure, and stroke also had important impacts.

CONCLUSIONS

Within the limitations of the modelling study, intensive glycaemic control with metformin was cost- and life-saving in overweight type-2 diabetes patients in the Swiss setting.

The cost-effectiveness of different management strategies for type I diabetes: a Swiss perspective

AIMS/HYPOTHESIS

A computer model was developed to determine the health outcomes and economic consequences of different combinations of diabetes interventions in newly diagnosed patients with Type I (insulin-dependent) diabetes in Switzerland.

METHODS

We modelled seven complications of diabetes: hypoglycaemia, ketoacidosis, acute myocardial infarction, stroke, lower extremity amputation, nephropathy, and retinopathy. Transition probabilities and costs were taken from published literature. The Swiss health insurance payer perspective was taken. Various combinations of diabetes management strategies, including intensive or conventional insulin therapy and screening and treatment strategies for renal and eye disease were defined. Life expectancy, cumulative incidences of complications, and mean expected total lifetime costs per patient were calculated under six different management strategies. Incremental cost-effectiveness ratios were calculated in terms of costs per life-year gained compared with conventional insulin therapy alone.

RESULTS

The addition of screening for microalbuminuria and retinopathy followed by appropriate treatment, if detected, were cost saving, with reduction in cumulative incidence of end stage renal disease and blindness respectively, and, in the case of microalbulminuria screening and treatment, an improvement in life expectancy. Intensive therapy improved life expectancy but increased total lifetime costs.

CONCLUSION/INTERPRETATION

Optimal management of Type I diabetic patients, including secondary and tertiary prevention, leads to reduced complications and improved life expectancy, with the increased costs of prevention offset to varying degrees by cost savings due to complications avoided.

[Screening, diagnosis and management of diabetes mellitus and diabetic complications]

Diabetes mellitus comprises a group of metabolic disturbances that are characterized by hyperglycemia. In 1997 the American Diabetes Association (ADA) proposed new criteria for the diagnosis and classification of diabetes mellitus, which was also adopted by WHO. Although the criteria is the same, the ADA puts emphasis on the use of the fasting plasma glucose (FPG) for screening and diagnosis, whereas WHO maintains the use of the OGTT and recommends the FPG only if an OGTT can not be performed. Different pathogenetic processes are involved in the development of diabetes ranging from autoimmune destruction of beta-cells resulting in an absolute insulin deficiency to insulin with a defect on insulin secretion. The new classification is based on the etiology of the disease. Diabetes is classified into one of four categories: Type-1, type-2 Diabetes mellitus, specific forms of diabetes, and gestational diabetes. For screening and diagnosis FPG or the two hour value after the OGTT can be used. Glycosylated hemoglobin is not suitable for screening and diagnosis of diabetes despite some contradictory statements. For many decades clear evidence was missing that chronic hyperglycemia caused diabetic late complications; complications including dysfunction or failure of several organ systems, in particular eyes, kidneys, nerves, and the cardiovascular system. The results of two large prospective trials--the Diabetes Control and Complications Trial (DCCT; 1993) and the United Kingdom Prospective Study (UKPDS; 1998)--that were recently published provided the final proof that normoglycemia prevents or delays the progression of these late complications. Due to the insidious nature of these complications they are often not diagnosed and have to be looked for in each patients with diabetes and have to be controlled regularly. Based on the results of the UKPDS and other studies, evidence based therapeutic goals could be defined. Multifactorial interventions with increased physical activity, cessation of smoking, aspirin treatment, lowering of HbA1c, blood pressure, and lipids in patients with type 2 diabetes have been proven to drastically reduce the risk of developing diabetic nephropathy or cardiovascular complications drastically. We recommend the following treatment strategy for patients with type 2 diabetes in clinical practice: 1) Treatment should be individualized. 2) Treatment should be started step by step to document efficacy of treatment and compliance of patients. 3) Plasma glucose and blood pressure should be normalized in all patients with type 2 diabetes (up to an age of 70 years), since there are no threshold values for HbA1c and blood pressure. 4) Therapeutic goals should be checked every three to six months. 5) In the case that therapeutic goals can not be met, treatment should be intensified. Often a combination therapy with many different drugs is required. 6) A specialist for diabetes should be consulted, if the therapeutic goals can not be met over a period of six months.

Evaluation of gastric emptying and motility in diabetic gastroparesis with magnetic resonance imaging: effects of cisapride

OBJECTIVE

The motor mechanisms that underlie both slow gastric emptying in diabetic gastroparesis and its acceleration by cisapride are poorly understood. We have recently shown that magnetic resonance imaging (MRI) allows concurrent evaluation of both gastric emptying and regional gastric motility.

METHODS

Emptying and motility were measured in eight diabetic patients with previously demonstrated delayed gastric emptying using a rapid MRI technique during oral administration of cisapride and placebo. Studies were performed in a double blind fashion and each patient acted as his own control. Subjects were studied supine for 120 min in a 1.5 Tesla MRI scanner after ingestion of 500 ml of 10% Intralipid. Gastric emptying corrected for the volume of secretions was determined every 15 min using transaxial scans. Each transaxial scan was followed by 120 coronal scans at 1 s intervals. Coronal scans were angled to provide simultaneous imaging of the proximal and distal stomach. MRI studies were also performed in seven diabetic patients with normal emptying who served as disease controls.

RESULTS

Emptying was slower in the gastroparetic patients (t(1/2): 124 +/- 10 min) compared to patients with normal emptying (81 +/- 9 min, p < 0.05). Cisapride accelerated gastric emptying (74 +/- 5 vs 124 +/- 10 min) in patients with gastroparesis. The contraction amplitudes in the proximal stomach of gastroparetic patients were increased during cisapride treatment (17.2% +/- 1.8% vs 13.2% +/- 0.6%; p < 0.02), whereas antral contraction frequency, amplitude, and velocity were unchanged.

CONCLUSIONS

We conclude that cisapride-induced acceleration of liquid gastric emptying in diabetic gastroparesis does not appear to result from changes in antral contractility, but may be related to changes in proximal gastric tone or gastric outlet resistance.

Using fasting plasma glucose concentrations to screen for gestational diabetes mellitus: prospective population based study

OBJECTIVE

To evaluate whether measuring fasting plasma glucose concentration is an easier screening procedure for gestational diabetes mellitus than the 1 hour 50 g glucose challenge test.

DESIGN

Prospective population based study.

SETTING

Outpatient clinic in a university hospital.

PARTICIPANTS

520 pregnant women (328 (63%) white, 99 (19%) Asian, 31 (6%) African, 62 (12%) others) with mean age 28.4 (SD 0.2; range 17-45) years. All underwent a glucose challenge test between the 24th and 28th gestational week, followed by a diagnostic 3 hour 100 g oral glucose tolerance test within one week. This was done irrespective of the result of the challenge test.

MAIN OUTCOME MEASURE

Receiver operating curves were used to determine the best cut off values for screening with fasting plasma glucose concentrations.

RESULTS

Fasting plasma glucose concentration at a threshold value of 4.8 mmol/l and the glucose challenge test with a threshold value of 7.8 mmol/l yielded sensitivities of 81% and 59% respectively and specificities of 76% and 91% respectively. Measuring fasting plasma glucose concentration as a screening procedure required a diagnostic test in 30%, compared with 14% when the challenge test was used.

CONCLUSIONS

Measuring fasting plasma glucose concentrations using a cut off value of >/=4. 8 mmol/l is an easier screening procedure for gestational diabetes than the 50 g glucose challenge test and allows 70% of women to avoid the challenge test.

[Cushing syndrome due to ectopic ACTH secretion: an uncommon case presentation, diagnosis and therapy]

Ectopic ACTH secretion due to malignant tumours is the most frequently underdiagnosed form of Cushing's syndrome. The majority of neoplasms causing ectopic ACTH syndrome are small-cell cancers of the lung or carcinoids. Other well-documented cases include adenocarcinoma of the lung, medullary thyroid carcinoma, pancreatic islet tumours and malignant thymoma. We report a rare case of metastatic colonic adenocarcinoma with ectopic ACTH syndrome. Clinical features such as proximal muscle weakness, peripheral oedema, hypertension or hirsutism in women, or the presence of unexplained hyperglycaemia, hypokalaemia or metabolic alkalosis in patients with known malignancy strongly suggest ectopic ACTH syndrome. Removal of the source of ACTH is the treatment of first choice, but often not feasible. Most often, treatment modalities are only palliative, with drugs directed against hypercortisolism such as aminoglutethimide, metyrapone, ketoconazole or mifepristone.

Relapsing Whipple's disease presenting with hypopituitarism

A 44-year-old man with a history of Whipple's disease 8 years ago presented with recurrent grand mal seizures and signs of hypopituitarism on physical examination. Magnetic resonance imaging of the brain revealed a hypothalamic lesion of 1 cm diameter in the region of the rostral infundibulum. Hypopituitarism was confirmed by low levels of serum cortisol, free testosterone and free thyroxine without an elevated TSH. Whipple encephalitis with hypothalamic involvement was suggested and verified by positive polymerase chain reaction (PCR) for Tropheryma whippelii in the cerebrospinal fluid. PCR for T. whippelii has become an important diagnostic tool for establishing the diagnosis of Whipple's disease especially in patients with unusual presentations and if the diagnosis cannot be confirmed histologically. Whipple's disease should be included in the differential diagnosis in hypopituitarism caused by infectious disease.

[Progressive decline in athletic performance]

A 48-year old engineer presented with progressive decline in sports performance. A history of latent hypothyroidism was known since 3 years. Adrenocortical insufficiency was suggested and confirmed by further investigations. Because of additional autoimmune thyroiditis and family history with autoimmune diabetes of the son, the diagnosis polyglandular autoimmune syndrome type II was made.

The early phase of glucose-stimulated insulin secretion requires nitric oxide

Nitric oxide (nitrogen monoxide, NO) acts as a signal transducer in a variety of cells. In the present study rat pancreatic islets were perifused with physiologically relevant glucose concentrations in the presence or absence of various NO-modulating agents. Perifusion in the presence of 0.1-1 mmol/l of the NO synthase inhibitor, NG-monomethyl-L-arginine or of 10 micromol/l of the NO-scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), resulted in an inhibition of the early phase of glucose-stimulated insulin secretion by 60-65% and 46%, respectively. Light- and electron-microscopic studies revealed that pancreatic islets constitutively express NO-synthase in alpha and delta cells, where it is confined to the secretory granules. Therefore, these data indicate that NO may be important in the signal transduction pathway of the early phase of glucose-stimulated insulin secretion.