Prediction of mortality and macrovascular complications in type 2 diabetes: validation of the UKPDS Outcomes Model in the Casale Monferrato Survey, Italy.

AIMS/HYPOTHESIS: The United Kingdom Prospective Diabetes Study (UKPDS) Outcomes Model can be used to estimate the lifetime occurrence of major diabetes-related complications in order to calculate health economic outcomes. The aim of the study was to assess the performance of the model by comparing the predicted and observed mortality and the incidence of macrovascular complications in an Italian population-based cohort with type 2 diabetes. METHODS: We used data from the Casale Monferrato Survey, a cohort enrolled in 1988 and surveyed in 1991 (n = 1,967) to assess the prevalence of cardiovascular risk factors. In 2000, a new survey included all the members of the original cohort who were still alive (n = 860), and in addition all individuals identified with a new diagnosis of type 2 diabetes since 1993 (n = 2,389). We compared the mortality predicted by the model for the 1991 survey over the subsequent 17-year period with the observed risk. The following outcomes were analysed in the 2000 survey: myocardial infarction (MI), other ischaemic heart disease, stroke, congestive heart failure (CHF) and amputation. RESULTS: For all-cause mortality, the predictions from the model at 5 and 10 years (23% and 47%, respectively) were identical to the observed risks. At 15 years, the risk of death was slightly overestimated (an estimate of 67% vs 64% observed, 95% CI 61%, 66%). The performance of the model was best for patients with a recent history of disease (duration <6 years). Among the complications, the predicted cumulative incidences of MI and CHF were very close to those observed. CONCLUSIONS/INTERPRETATION: External validation is essential to assess the accuracy of simulation models. The UKPDS Outcomes Model satisfactorily predicted a set of actual incidences of mortality and complications in an Italian diabetes cohort up to a duration of approximately 12 years. The longer term performance of such models should be carefully evaluated.

Hypoglycemia is independently associated with multidimensional impairment in elderly diabetic patients.

AIM: To identify the characteristics associated with multidimensional impairment, evaluated through the Multidimensional Prognostic Index (MPI), a validated predictive tool for mortality derived from a standardized Comprehensive Geriatric Assessment (CGA), in a cohort of elderly diabetic patients treated with oral hypoglycemic drugs. METHODS AND RESULTS: The study population consisted of 1342 diabetic patients consecutively enrolled in 57 diabetes centers distributed throughout Italy, within the Metabolic Study. Inclusion criteria were diagnosis of type 2 diabetes mellitus (DM), 65 years old or over, and treatment with oral antidiabetic medications. Data concerning DM duration, medications for DM taken during the 3-month period before inclusion in the study, number of hypoglycemic events, and complications of DM were collected. Multidimensional impairment was assessed using the MPI evaluating functional, cognitive, and nutritional status; risk of pressure sores; comorbidity; number of drugs taken; and cohabitation status. The mean age of participants was 73.3 ± 5.5 years, and the mean MPI score was 0.22 ± 0.13. Multivariate analysis showed that advanced age, female gender, hypoglycemic events, and hospitalization for glycemic decompensation were independently associated with a worse MPI score. CONCLUSION: Stratification of elderly diabetic patients using the MPI might help to identify those patients at highest risk who need better-tailored treatment.

Hippocampal heat shock protein 25 expression in streptozotocin-induced diabetic mice.

Hippocampal abnormalities are believed to increase the risk of cognitive decline in diabetic patients. The underlying mechanism is unknown, but both hyperglycemia and oxidative stress have been implicated. Cellular stresses induce the expression of heat shock protein 25 (HSP25) and this results in cytoprotection. Our aim was to assess hippocampal expression of HSP25 in experimental diabetes. Mice were rendered diabetic by streptozotocin injection. Ten weeks after diabetes onset hippocampal HSP25 expression was studied by immunoblotting and immunohistochemistry (IHC). Expression of glial fibrillary acidic protein, nitrotyrosine, iNOS, HSP72, HSP90, and Cu/Zn superoxide dismutase (SOD) was assessed by either IHC or immunoblotting, Cu/Zn-SOD activity by enzymatic assay, and malondialdehyde (MDA) content by colorimetric assay. Hippocampal HSP25 was significantly increased in diabetic as compared to non-diabetic animals and localized predominantly within the pyramidal neurons layer of the CA1 area. This was paralleled by overexpression of nitrotyrosine, iNOS, SOD expression/activity, and enhanced MDA content. In experimental diabetes, HSP25 is overexpressed in the CA1 pyramidal neurons in parallel with markers of oxidative stress.

Antiangiogenic and immunomodulatory effects of rapamycin on islet endothelium: relevance for islet transplantation.

Donor intra-islet endothelial cells contribute to neovascularization after transplantation. Several factors may interfere with this process and ultimately influence islet engraftment. Rapamycin, a central immunosuppressant in islet transplantation, is an mTOR inhibitor that has been shown to inhibit cancer angiogenesis. The aim of this study was to evaluate the effects of rapamycin on islet endothelium. Rapamycin inhibited the outgrowth of endothelial cells from freshly purified human islets and the formation of capillary-like structures in vitro and in vivo after subcutaneous injection within Matrigel plugs into SCID mice. Rapamycin decreased migration, proliferation and angiogenic properties of human and mouse islet-derived endothelial cell lines with appearance of apoptosis. The expression of angiogenesis-related factors VEGF, alphaVbeta3 integrin and thrombospondin-1 on islet endothelium was altered in the presence of rapamycin. On the other hand, rapamycin decreased the surface expression of molecules involved in immune processes such as ICAM-1 and CD40 and reduced the adhesion of T cells to islet endothelium. Our results suggest that rapamycin exerts dual effects on islet endothelium inducing a simultaneous inhibition of angiogenesis and a down-regulation of receptors involved in lymphocyte adhesion and activation.

Primary and immortalised human pancreatic islet endothelial cells: phenotypic and immunological characterisation.

AIMS/HYPOTHESIS: Studies on the biology of the microvascular endothelial cells (MECs) that surround and penetrate the pancreatic islets are hampered by difficulties in isolating and culturing large numbers of pure cells. We aimed to morphologically and functionally characterise primary MECs purified and cultured from human islets, and to establish a simian virus 40 (SV40)-immortalised cell line from these primary cultures. MATERIALS AND METHODS: Human islet MECs were extracted and purified using anti-CD105 coated immunomagnetic beads, and endothelial markers and surface molecules analysed by flow cytometric analysis. An immortalised cell line was then established by using a chimeric adeno5/SV40 virus. RESULTS: Islet MECs expressed classic and specific endothelial markers, a high basal level of intercellular adhesion molecule-1, and low levels of E-selectin and TNF (previously known as TNF-alpha) inducible vascular cell adhesion molecule-1. IFNG (previously known as IFN-gamma) induced expression of HLA class II molecules. The immortalised islet MECs expanded rapidly, exhibited increased DNA synthesis, and were passaged approximately 30 times, without signs of senescence. They retained the endothelial characteristics of the parental cells, and behaved as the primary cells in terms of TNF stimulation of expression of adhesion molecules and support of leucocyte adhesion and transmigration. CONCLUSIONS/INTERPRETATION: The immortalised islet MECs that we have established could effectively represent a substitute for primary counterparts for in vitro studies on the role of the microvasculature in pathophysiological processes involved in type 1 and type 2 diabetes.

Sex-differences in prevalence of electrocardiographic left ventricular hypertrophy in Type 2 diabetes: the Casale Monferrato Study.

UNLABELLED: AIMS Although left ventricular hypertrophy (LVH) defined by either standard 12-lead ECG or echocardiography strongly predicts cardiovascular mortality, its prevalence in Type 2 diabetes is largely unknown. We have assessed prevalence of ECG-LVH and its relationship with clinical and metabolic variables in an Italian population-based cohort of subjects with Type 2 diabetes. METHODS The study-base was 965 (61.3%) subjects with Type 2 diabetes of the population-based cohort living in Casale Monferrato (Italy). LVH was defined by ECG Cornell voltage-duration product. All measurements were centralized. RESULTS ECG-LVH was diagnosed in 165/965 subjects, giving a prevalence of 17.1% (95% CI 14.7-19.5). Large sex differences were found, with higher prevalence in women (23.5%, 19.9-27.0) than in men (8.4%, 5.6-11.0), even after adjustment for age, BMI and hypertension (OR 3.83, 95% CI 2.5-5.9). At the examination, subjects with ECG-LVH were older than those without it. Similar age- and sex-adjusted values of HbA(1c), plasma lipids, fibrinogen, uric acid and creatinine were found in the two subgroups. No differences in prevalence of hypertension, CHD, increased QT duration or dispersion, micro- and macro-albuminuria were found between subjects with ECG-LVH and those without it. In logistic regression analysis, variables independently associated with ECG-LVH, after age-adjustment, were sex and diastolic blood pressure. CONCLUSIONS: This population-based study shows: (i) a high prevalence of ECG-LVH in Type 2 diabetic subjects; (ii) 3-fold higher risk in women than in men, independently of age, BMI, and blood pressure; (iii) an independent association between ECG-LVH and diastolic blood-pressure. Screening for ECG-LVH in diabetic subjects is therefore recommended, particularly in diabetic women.