Showing papers in "Diabetologia in 2008"

The mechanisms of alloxan- and streptozotocin-induced diabetes.

Abstract: Alloxan and streptozotocin are toxic glucose analogues that preferentially accumulate in pancreatic beta cells via the GLUT2 glucose transporter. In the presence of intracellular thiols, especially glutathione, alloxan generates reactive oxygen species (ROS) in a cyclic redox reaction with its reduction product, dialuric acid. Autoxidation of dialuric acid generates superoxide radicals, hydrogen peroxide and, in a final iron-catalysed reaction step, hydroxyl radicals. These hydroxyl radicals are ultimately responsible for the death of the beta cells, which have a particularly low antioxidative defence capacity, and the ensuing state of insulin-dependent 'alloxan diabetes'. As a thiol reagent, alloxan also selectively inhibits glucose-induced insulin secretion through its ability to inhibit the beta cell glucose sensor glucokinase. Following its uptake into the beta cells, streptozotocin is split into its glucose and methylnitrosourea moiety. Owing to its alkylating properties, the latter modifies biological macromolecules, fragments DNA and destroys the beta cells, causing a state of insulin-dependent diabetes. The targeting of mitochondrial DNA, thereby impairing the signalling function of beta cell mitochondrial metabolism, also explains how streptozotocin is able to inhibit glucose-induced insulin secretion.

Prediction of outcome in individuals with diabetic foot ulcers: focus on the differences between individuals with and without peripheral arterial disease. The EURODIALE Study

Abstract: Aims/hypothesis Outcome data on individuals with diabetic foot ulcers are scarce, especially in those with peripheral arterial disease (PAD). We therefore examined the clinical characteristics that best predict poor outcome in a large population of diabetic foot ulcer patients and examined whether such predictors differ between patients with and without PAD.

Vitamin B12 and folate concentrations during pregnancy and insulin resistance in the offspring: the Pune Maternal Nutrition Study.

Abstract: Aims/hypothesis Raised maternal plasma total homocysteine (tHcy) concentrations predict small size at birth, which is a risk factor for type 2 diabetes mellitus. We studied the association between maternal vitamin B12, folate and tHcy status during pregnancy, and offspring adiposity and insulin resistance at 6 years.

Caesarean section is associated with an increased risk of childhood-onset type 1 diabetes mellitus: a meta-analysis of observational studies.

Abstract: Aims/hypothesis The aim of this study was to investigate the evidence of an increased risk of childhood-onset type 1 diabetes in children born by Caesarean section by systematically reviewing the published literature and performing a meta-analysis with adjustment for recognised confounders.

Arterial stiffness in diabetes and the metabolic syndrome: a pathway to cardiovascular disease

Abstract: Increased arterial stiffness associated with diabetes and the metabolic syndrome may in part explain the increased cardiovascular disease risk observed in these conditions. Arterial stiffness can be estimated by quantifying pulse pressure but is better described by distensibility and compliance coefficients, pulse wave velocity and wave reflection. The most common non-invasive methodologies used to quantify these estimates of arterial stiffness (e.g. ultrasonography and applanation tonometry) are also described. We then review and summarise the current data on the associations between diabetes, the metabolic syndrome and insulin resistance on the one hand and greater arterial stiffness on the other, and identify and discuss some unresolved issues such as differential stiffening of central vs peripheral arterial segments, the impact of sex, and the pathobiology of increased arterial stiffness in diabetes and the metabolic syndrome. Finally, some considerations with regard to treatment options are presented. At present the most powerful therapy available for reducing arterial stiffness is to vigorously treat hypertension using pharmacological agents. New pharmacological strategies to reduce arterial stiffness are likely to be especially relevant to individuals with diabetes.

A randomised, 52-week, treat-to-target trial comparing insulin detemir with insulin glargine when administered as add-on to glucose-lowering drugs in insulin-naive people with type 2 diabetes

Abstract: Aims/hypothesis This 52-week multinational, randomised, open-label, parallel-group, non-inferiority trial compared clinical outcomes following supplementation of oral glucose-lowering drugs with basal insulin analogues detemir and glargine in type 2 diabetic patients.

Epigenetic regulation of PPARGC1A in human type 2 diabetic islets and effect on insulin secretion

Abstract: Aims/hypothesis Insulin secretion in pancreatic islets is dependent upon mitochondrial function and production of ATP. The transcriptional coactivator peroxisome proliferator activated receptor gamma coactivator-1 alpha (protein PGC-1α; gene PPARGC1A) is a master regulator of mitochondrial genes and its expression is decreased and related to impaired oxidative phosphorylation in muscle from patients with type 2 diabetes. Whether it plays a similar role in human pancreatic islets is not known. We therefore investigated if PPARGC1A expression is altered in islets from patients with type 2 diabetes and whether this expression is influenced by genetic (PPARGC1A Gly482Ser polymorphism) and epigenetic (DNA methylation) factors. We also tested if experimental downregulation of PPARGC1A expression in human islets influenced insulin secretion.

Best practice guidelines for the molecular genetic diagnosis of maturity-onset diabetes of the young

Abstract: Aims/hypothesis Mutations in the GCK and HNF1A genes are the most common cause of the monogenic forms of diabetes known as ‘maturity-onset diabetes of the young’. GCK encodes the glucokinase enzyme, which acts as the pancreatic glucose sensor, and mutations result in stable, mild fasting hyperglycaemia. A progressive insulin secretory defect is seen in patients with mutations in the HNF1A and HNF4A genes encoding the transcription factors hepatocyte nuclear factor-1 alpha and -4 alpha. A molecular genetic diagnosis often changes management, since patients with GCK mutations rarely require pharmacological treatment and HNF1A/4A mutation carriers are sensitive to sulfonylureas. These monogenic forms of diabetes are often misdiagnosed as type 1 or 2 diabetes. Best practice guidelines for genetic testing were developed to guide testing and reporting of results. Methods A workshop was held to discuss clinical criteria for testing and the interpretation of molecular genetic test results. The participants included 22 clinicians and scientists from 13 countries. Draft best practice guidelines were formulated and edited using an online tool (http://www. coventi.com). Results An agreed set of clinical criteria were defined for the testing of babies, children and adults for GCK, HNF1A and HNF4A mutations. Reporting scenarios were discussed and consensus statements produced. Conclusions/interpretation Best practice guidelines have been established for monogenic forms of diabetes caused by mutations in the GCK, HNF1A and HNF4A genes. The guidelines include both diagnostic and predictive genetic tests and interpretation of the results.

Increased risk of cardiovascular disease in non-alcoholic fatty liver disease: causal effect or epiphenomenon?

Abstract: Non-alcoholic fatty liver disease (NAFLD), comprising a spectrum of conditions ranging from pure steatosis to steatohepatitis and cirrhosis, has reached epidemic proportions and represents the most common cause of chronic liver disease in the community. The prevalence of NAFLD has been estimated to be between 20% and 30% in the general population, but this value is much higher (∼70–80%) in type 2 diabetic patients, who are also at higher risk of developing advanced fibrosis and cirrhosis. Increasing recognition of the importance of NAFLD and its strong relationship with the metabolic syndrome has stimulated an interest in the possible role of NAFLD in the development of cardiovascular disease (CVD). Several epidemiological studies indicate that NAFLD, especially in its more severe forms, is linked to an increased risk of CVD, independently of underlying cardiometabolic risk factors. This suggests that NAFLD is not merely a marker of CVD, but may also be actively involved in its pathogenesis. The possible molecular mediators linking NAFLD and CVD include the release of pro-atherogenic factors from the liver (C-reactive protein, fibrinogen, plasminogen activator inhibitor-1 and other inflammatory cytokines) as well as the contribution of NAFLD per se to whole-body insulin resistance and atherogenic dyslipidemia, in turn favouring CVD progression. The clinical impact of NAFLD on CVD risk deserves particular attention in view of the implications for screening and surveillance strategies in the growing number of patients with NAFLD.

Continuous subcutaneous insulin infusion versus multiple daily insulin injections in patients with diabetes mellitus: systematic review and meta-analysis

Abstract: Aims We compared the effects of continuous subcutaneous insulin infusion (CSII) with those of multiple daily insulin (MDI) injections on glycaemic control, risk of hypoglycaemic episodes, insulin requirements and adverse events in type 1 and type 2 diabetes mellitus.

What is the mechanism of microalbuminuria in diabetes: a role for the glomerular endothelium?

Abstract: Microalbuminuria is an important risk factor for cardiovascular disease and progressive renal impairment. This holds true in the general population and particularly in those with diabetes, in whom it is common and marks out those likely to develop macrovascular disease and progressive renal impairment. Understanding the pathophysiological mechanisms through which microalbuminuria occurs holds the key to designing therapies to arrest its development and prevent these later manifestations.

The association between ultraviolet B irradiance, vitamin D status and incidence rates of type 1 diabetes in 51 regions worldwide

Abstract: Aims/hypothesis This study is an analysis of the relationship between ultraviolet B (UVB) irradiance, the primary source of circulating vitamin D in humans, and age-standardised incidence rates of type 1 diabetes mellitus in children, according to region of the world.

The Danish National Diabetes Register: trends in incidence, prevalence and mortality.

Abstract: Aims/hypothesis The aim of the study was to describe trends in the incidence rate, prevalence and mortality rate for diabetes in Denmark.

Non-alcoholic fatty liver disease is independently associated with an increased prevalence of chronic kidney disease and proliferative/laser-treated retinopathy in type 2 diabetic patients

Abstract: Aims/hypothesis Non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiovascular disease in type 2 diabetes. Currently, there is a lack of information on associations between NAFLD and microvascular complications of diabetes. We assessed the associations between NAFLD and both chronic kidney disease (CKD) and retinopathy in a large cohort of type 2 diabetic individuals using a cross-sectional design.

Newly identified loci highlight beta cell dysfunction as a key cause of type 2 diabetes: where are the insulin resistance genes?

Abstract: Although type 2 diabetes has been traditionally understood as a metabolic disorder initiated by insulin resistance, it has recently become apparent that an impairment in insulin secretion contributes to its manifestation and may play a prominent role in its early pathophysiology. The genetic dissection of Mendelian and, more recently, polygenic types of diabetes confirms the notion that primary defects in insulin synthesis, processing and/or secretion often give rise to the common form of this disorder. This concept, first advanced with the discovery and physiological characterisation of various genetic subtypes of MODY, has been extended to other forms of monogenic diabetes (e.g. neonatal diabetes). It has also led to the identification of common risk variants via candidate gene approaches (e.g. the E23K polymorphism in KCNJ11 or common variants in the MODY genes), and it has been validated by the description of the robust physiological effects conferred by polymorphisms in the TCF7L2 gene. More recently, the completion and integration of genome-wide association scans for this disease has uncovered a number of heretofore unsuspected variants, several of which also affect insulin secretion. This review provides an up-to-date account of genetic loci that influence risk of common type 2 diabetes via impairment of beta cell function, outlines their presumed mechanisms of action, and places them in the context of gene-gene and/or gene-environment interactions. Finally, a strategy for the analogous discovery of insulin resistance genes is proposed.

Pathogenesis of type 2 diabetes: tracing the reverse route from cure to cause

Abstract: The metabolic abnormalities of type 2 diabetes can be reversed reproducibly by bariatric surgery. By quantifying the major pathophysiological abnormalities in insulin secretion and insulin action after surgery, the sequence of events leading to restoration of normal metabolism can be defined. Liver fat levels fall within days and normal hepatic insulin sensitivity is restored. Simultaneously, plasma glucose levels return towards normal. Insulin sensitivity of muscle remains abnormal, at least over the weeks and months after bariatric surgery. The effect of the surgery is explicable solely in terms of energy restriction. By combining this information with prospective observation of the changes immediately preceding the onset of type 2 diabetes, a clear picture emerges. Insulin resistance in muscle, caused by inherited and environmental factors, facilitates the development of fatty liver during positive energy balance. Once established, the increased insulin secretion required to maintain plasma glucose levels will further increase liver fat deposition. Fatty liver causes resistance to insulin suppression of hepatic glucose output as well as raised plasma triacylglycerol. Exposure of beta cells to increased levels of fatty acids, derived from circulating and locally deposited triacylglycerol, suppresses glucose-mediated insulin secretion. This is reversible initially, but eventually becomes permanent. The essential time sequence of the pathogenesis of type 2 diabetes is now evident. Muscle insulin resistance determines the rate at which fatty liver progresses, and ectopic fat deposition in liver and islet underlies the related dynamic defects of hepatic insulin resistance and beta cell dysfunction. These defects are capable of dramatic reversal under hypoenergetic feeding conditions, completely in early diabetes and to a worthwhile extent in more established disease.

Polymorphisms in the TCF7L2, CDKAL1 and SLC30A8 genes are associated with impaired proinsulin conversion.

Abstract: Aims/hypothesis Variation within six novel genetic loci has been reported to confer risk of type 2 diabetes and may be associated with beta cell dysfunction. We investigated whether these polymorphisms are also associated with impaired proinsulin to insulin conversion.

Resource utilisation and costs associated with the treatment of diabetic foot ulcers. Prospective data from the Eurodiale Study

Abstract: Aims/hypothesis The aim of the present study was to investigate resource utilisation and associated costs in patients with diabetic foot ulcers and to analyse differences in resource utilisation between individuals with or without peripheral arterial disease (PAD) and/or infection.

The endocannabinoid system in obesity and type 2 diabetes

Abstract: Endocannabinoids (ECs) are defined as endogenous agonists of cannabinoid receptors type 1 and 2 (CB1 and CB2). ECs, EC anabolic and catabolic enzymes and cannabinoid receptors constitute the EC signalling system. This system participates in the control of lipid and glucose metabolism at several levels, with the possible endpoint of the accumulation of energy as fat. Following unbalanced energy intake, however, the EC system becomes dysregulated, and in most cases overactive, in several organs participating in energy homeostasis, particularly, in intra-abdominal adipose tissue. This dysregulation might contribute to excessive visceral fat accumulation and reduced adiponectin release from this tissue, and to the onset of several cardiometabolic risk factors that are associated with obesity and type 2 diabetes. This phenomenon might form the basis of the mechanism of action of CB1 antagonists/inverse agonists, recently developed by several pharmaceutical companies as adjuvants to lifestyle modification for weight reduction, glycaemic control and dyslipidaemia in obese and type 2 diabetes patients. It also helps to explain why some of the beneficial actions of these new therapeutics appear to be partly independent from weight loss.

Diabetes Antibody Standardization Program: evaluation of assays for autoantibodies to glutamic acid decarboxylase and islet antigen-2.

Abstract: Islet autoantibodies are important in diabetes classification and risk assessment, and as endpoints in observational studies. The Diabetes Autoantibody Standardization Program (DASP) aims to improve and standardise measurement of autoantibodies associated with type 1 diabetes. We report results for glutamic acid decarboxylase autoantibodies (GADA) and islet antigen-2 autoantibodies (IA-2A) from three DASP workshops (2002–2005). Up to 60 laboratories in 18 countries participated in each workshop. Participants received coded serum aliquots from 50 patients with newly diagnosed type 1 diabetes (median age 18 years, range 9–35 years) and 100 blood donor controls. Results were analysed using receiver operator characteristic (ROC) curves with sensitivity adjusted to 95% specificity in workshop controls. GADA assays performed well in all three workshops (median area under the ROC curve [AUC] 0.94; interquartile range 0.91–0.95) and performance was similar to DASP 2000. Performance of IA-2A assays improved over the workshop programme. Median AUC was 0.81 (interquartile range 0.79–0.83) in DASP 2002, 0.82 (interquartile range 0.78–0.84) in 2003, and 0.85 (interquartile range 0.82–0.87) in 2005 (p < 0.0001). Performance of GADA ELISA improved between 2002 and 2005, and, in DASP 2005, achieved higher median AUC and adjusted sensitivity than RIA. IA-2A ELISA improved and, in DASP 2005, achieved AUCs equivalent to in-house RIA. Assays using IA-2ic or full length IA-2 clones were more sensitive than those using IA-2bdc, with higher AUC (p = 0.004). GADA and IA-2A assays perform well in discriminating health and disease. The workshop format highlights systematic differences related to assay method and allows full evaluation of novel methods. The programme of autoantibody workshops in type 1 diabetes provides a model for other autoimmune diseases.

Glucagon-like peptide-1, but not glucose-dependent insulinotropic peptide, inhibits glucagon secretion via somatostatin (receptor subtype 2) in the perfused rat pancreas

Abstract: Aims/hypothesis The glucose-lowering effect of glucagon-like peptide-1 (GLP-1) is based not only upon its potent insulinotropic actions but also on its ability to restrain glucagon secretion. Surprisingly, the closely related glucose-dependent insulinotropic peptide (GIP) stimulates glucagon release. We examined whether the islet hormone somatostatin, which strongly inhibits glucagon secretion, is involved in this divergent behaviour.

Metformin and the intestine.

Abstract: To the Editor: The antihyperglycaemic effect of metformin is generally attributed to a decrease in hepatic glucose output, with some additional effects that increase peripheral glucose uptake and utilisation [1]. The intestine also makes an important contribution to the glucose-lowering effect of metformin, but this is often overlooked because of a paucity of clinical data [2]. Animal studies indicate that metformin can cause intestinal glucose absorption to be delayed and occur more distally along the tract [3, 4]. However, animal studies have also shown that metformin increases glucose utilisation by the intestine, particularly anaerobic glucose metabolism [5–7], and this contributes to an apparent shortfall in the passage of glucose from the luminal to the serosal side of the intestine [3]. Extra lactate delivered into the portal vein is at least partly converted into glucose, increasing glucose turnover after administration of metformin [5,7,8]. We demonstrate here that metformin increases lactate production in human intestinal mucosa, similar to reports in animal studies. Animal studies have long established that very high concentrations of metformin accumulate in the wall of the intestine [9], which may at least partly explain the increase in anaerobic metabolism. We provide confirmatory evidence herein that similarly high concentrations of metformin accumulate in the human intestinal mucosa. In the present study, eight recently diagnosed, drug-naive, obese type 2 diabetic patients [five men, three women; age 55±3 years (mean±SEM); BMI 33±1 kg/m] attended on three occasions after an overnight fast. Patients gave informed consent, and ethical approval was granted by the research ethics committee. Avenous blood sample was taken for plasma glucose assay (automated glucose oxidase method), and a mucosal biopsy sample (approximately 25 mg) was taken on each occasion from the proximal jejunum, under light midazolam sedation, using an adapted paediatric gastroscope. On the first occasion, tissue was washed, divided into two portions, weighed and then incubated for 2 h at 37°C in 1 ml of Krebs Ringer bicarbonate buffer supplemented with 20 mg/ml serum albumin, 10 mmol/l glucose, 10 mol/l insulin with or without 10 mol/l metformin hydrochloride, and maintained in an atmosphere of 95% O2, 5% CO2 [4, 5]. Lactate production was measured as the concentration of lactate in the medium (manual spectrophotometric method). Metformin therapy was initiated at a dosage of 850 mg once daily and titrated up to twice daily after 2–3 weeks. Two repeat proximal jejunal mucosal biopsies were obtained after 6–8 weeks of therapy. A pre-dose sample was obtained in the morning, 12–16 h after the last metformin tablet (taken the evening before), and a post-dose sample was taken 3 h after the morning tablet. Tissue samples were washed in buffered saline, blotted and weighed, and then metformin was extracted with acetonitrile and assayed by gas chromatography [10]. The results showed that incubation of the jejunal biopsy tissue with 10 mol/l metformin increased lactate producDiabetologia (2008) 51:1552–1553 DOI 10.1007/s00125-008-1053-5

Intravitreous anti-VEGF for diabetic retinopathy: hopes and fears for a new therapeutic strategy

Abstract: Vascular endothelial growth factor (VEGF) plays a key role in the development of both proliferative diabetic retinopathy (PDR) and diabetic macular oedema (DMO). In recent years, anti-VEGF agents have emerged as new approaches to the treatment of these devastating diabetic complications. Although Phase III studies in the diabetic population are needed, intravitreal anti-VEGF therapy is currently being used in clinical practice. Intravitreal injection is an effective means of delivering anti-VEGF drugs to the retina. However, this is an invasive procedure associated with potentially serious complications, such as endophthalmitis or retinal detachment, which may be significant for patients requiring serial treatment over many years. In addition, although delivered within the vitreous, anti-VEGF drugs could pass into the systemic circulation, which could potentially result in hypertension, proteinuria, increased cardiovascular events and impaired wound healing. Pegaptanib, ranibizumab and bevacizumab are the currently available anti-VEGF agents. Ranibizumab and bevacizumab block all VEGF isoforms, thus impairing both physiological and pathological neovascularisation. Pegaptanib only blocks the VEGF165 isoform, and would therefore seem the best option for avoiding systemic adverse effects in diabetic patients, although this remains to be demonstrated in clinical trials. In this regard, head-to-head studies designed to evaluate not only the efficacy, but also the systemic adverse effects of these drugs in a high-risk population such as diabetic patients are warranted.

Socioeconomic inequalities in diabetes mellitus across Europe at the beginning of the 21st century

Abstract: Aims/hypothesis The aim of this study was to determine and quantify socioeconomic position (SEP) inequalities in diabetes mellitus in different areas of Europe, at the turn of the century, for men and women.

The WNT signalling pathway and diabetes mellitus

Abstract: The WNT signalling pathway is involved in many physiological and pathophysiological activities. WNT ligands bind to Frizzled receptors and co-receptors (LDL receptor-related protein 5/6), triggering a cascade of signalling events. The major effector of the canonical WNT signalling pathway is the bipartite transcription factor beta-catenin/T cell transcription factor (beta-cat/TCF), formed by free beta-cat and one of the four TCFs. The WNT pathway is involved in lipid metabolism and glucose homeostasis, and mutations in LRP5 may lead to the development of diabetes and obesity. beta-Cat/TCF is also involved in the production of the incretin hormone glucagon-like peptide-1 in the intestinal endocrine L cells. More recently, genome-wide association studies have identified TCF7L2 as a diabetes susceptibility gene, and individuals carrying certain TCF7L2 single nucleotide polymorphisms could be more susceptible to the development of type 2 diabetes. Furthermore, beta-cat is able to interact with forkhead box transcription factor subgroup O (FOXO) proteins. Since FOXO and TCF proteins compete for a limited pool of beta-cat, enhanced FOXO activity during ageing and oxidative stress may attenuate WNT-mediated activities. These observations shed new light on the pathogenesis of type 2 diabetes as an age-dependent disease.

Presence of functional cannabinoid receptors in human endocrine pancreas.

Abstract: We examined the presence of functional cannabinoid receptors 1 and 2 (CB1, CB2) in isolated human islets, phenotyped the cells producing cannabinoid receptors and analysed the actions of selective cannabinoid receptor agonists on insulin, glucagon and somatostatin secretion in vitro. We also described the localisation on islet cells of: (1) the endocannabinoid-producing enzymes N-acyl-phosphatidyl ethanolamine-hydrolysing phospholipase D and diacylglycerol lipase; and (2) the endocannabinoid-degrading enzymes fatty acid amidohydrolase and monoacyl glycerol lipase. Real-time PCR, western blotting and immunocytochemistry were used to analyse the presence of endocannabinoid-related proteins and genes. Static secretion experiments were used to examine the effects of activating CB1 or CB2 on insulin, glucagon and somatostatin secretion and to measure changes in 2-arachidonoylglycerol (2-AG) levels within islets. Analyses were performed in isolated human islets and in paraffin-embedded sections of human pancreas. Human islets of Langerhans expressed CB1 and CB2 (also known as CNR1 and CNR2) mRNA and CB1 and CB2 proteins, and also the machinery involved in synthesis and degradation of 2-AG (the most abundant endocannabinoid, levels of which were modulated by glucose). Immunofluorescence revealed that CB1 was densely located in glucagon-secreting alpha cells and less so in insulin-secreting beta cells. CB2 was densely present in somatostatin-secreting delta cells, but absent in alpha and beta cells. In vitro experiments revealed that CB1 stimulation enhanced insulin and glucagon secretion, while CB2 agonism lowered glucose-dependent insulin secretion, showing these cannabinoid receptors to be functional. Together, these results suggest a role for endogenous endocannabinoid signalling in regulation of endocrine secretion in the human pancreas.

Outcomes of surgical treatment of diabetic foot osteomyelitis: a series of 185 patients with histopathological confirmation of bone involvement

Abstract: Aims/hypothesis We analysed the factors that determine the outcomes of surgical treatment of osteomyelitis of the foot in diabetic patients given early surgical treatment within 12 h of admission and treated with prioritisation of foot-sparing surgery and avoidance of amputation.

Intravitreous anti-VEGF for diabetic retinopathy : hopes and fears for a new therapeutic strategy. Commentary

Abstract: Vascular endothelial growth factor (VEGF) plays a key role in the development of both proliferative diabetic retinopathy (PDR) and diabetic macular oedema (DMO). In recent years, anti-VEGF agents have emerged as new approaches to the treatment of these devastating diabetic complications. Although Phase III studies in the diabetic population are needed, intravitreal anti-VEGF therapy is currently being used in clinical practice. Intravitreal injection is an effective means of delivering anti-VEGF drugs to the retina. However, this is an invasive procedure associated with potentially serious complications, such as endophthalmitis or retinal detachment, which may be significant for patients requiring serial treatment over many years. In addition, although delivered within the vitreous, anti-VEGF drugs could pass into the systemic circulation, which could potentially result in hypertension, proteinuria, increased cardiovascular events and impaired wound healing. Pegaptanib, ranibizumab and bevacizumab are the currently available anti-VEGF agents. Ranibizumab and bevacizumab block all VEGF isoforms, thus impairing both physiological and pathological neovascularisation. Pegaptanib only blocks the VEGF 165 isoform, and would therefore seem the best option for avoiding systemic adverse effects in diabetic patients, although this remains to be demonstrated in clinical trials. In this regard, head-to-head studies designed to evaluate not only the efficacy, but also the systemic adverse effects of these drugs in a high-risk population such as diabetic patients are warranted.

Association between age at menarche and risk of diabetes in adults: results from the EPIC-Norfolk cohort study

Abstract: Aims/hypothesis Earlier age at menarche is associated with increased BMI and obesity risk from early childhood through to adulthood. We hypothesised that earlier age at menarche would also predict subsequent diabetes risk.

Transcription factor expression in the developing human fetal endocrine pancreas

Abstract: Aims/hypothesis Morphological changes that occur during pancreatic endocrine cell differentiation have been shown in rodent systems to be dependent on sequential alterations in transcription factor expression. However, similar data for humans have been limited. The aim of the present study was to provide a connection between pancreatic morphology, transcription factor gene expression and protein localisation during human fetal development.