Setting research priorities for Type 1 diabetes

Diabet. Med. 29, 1321-1326 (2012) ABSTRACT: Aims Research priorities are often set by academic researchers or the pharmaceutical industry. The interests of patients, carers and clinicians may therefore be overlooked and research questions that matter may be neglected. The aims of this study were to collect uncertainties about the treatment of Type?1 diabetes from patients, carers and health professionals, and to collate and prioritize these uncertainties to develop a top 10 list of research priorities, using a structured priority-setting partnership of patients, carers, health professionals and diabetes organizations, as described by the James Lind Alliance. Methods A partnership of interested organizations was set up, and from this a steering committee of 10 individuals was formed. An online and paper survey was used to identify uncertainties. These were collated, and the steering group carried out an interim priority-setting exercise with partner organizations. This group of uncertainties was then voted on to give a smaller list that went forward to the final priority-setting workshop. At this meeting, a final list of the top 10 research priorities was agreed. Results An initial 1141 uncertainties were described. These were reduced to 88 indicative questions, 47 of which went out for voting. Twenty-four were then taken forward to a final priority-setting workshop. This workshop resulted in a list of top 10 research priorities in Type?1 diabetes. Conclusion We have shown that it is possible using the James Lind Alliance process to develop an agreed top 10 list of research priorities for Type?1 diabetes from health professionals, patients and carers.     

Type 1 diabetes as a relapsing-remitting disease?

Chronic immunological processes that underlie persistent viral infections and autoimmune disorders such as multiple sclerosis can be relapsing-remitting in nature. The progressive loss of beta-cell mass during the development of autoimmune type 1 diabetes (T1D) can also be non-linear, but the exact nature and kinetics of the immunological processes that govern T1D are not known. Here, we propose that the immunological process that is at the root of T1D is relapsing-remitting in nature and discuss the unresolved controversies and therapeutic implications of this hypothesis.     

Conformational Analysis of the Type II and Type III Collagen α-1 Chain C-Telopeptides by 1H NMR and Circular Dichroism Spectroscopy

Abstract

The type II and type III collagen α-1 chain C-telopeptides are a 27 mer with the sequence NAc- GPGIDMSAFAGLGPREKGPDPLQYMRA and a 22mer, NAc-GGGVASLGAGEKGPVG- YGYEYR, respectively. Their conformations have been studied in CD₃OH/H₂O (80/20) solution by means of two-dimensional proton NMR and CD spectroscopy. Based on TOCSY and NOESY experiments, all resonances were assigned and the conformational properties were analyzed in terms of vicinal NH-H_α coupling constants, sequential and medium range NOEs and amide proton temperature coefficients.

The conformation of the type II C-telopeptide is essentially extended. Evidence from CD spectroscopy suggests that a very minor proportion of the peptide might be helical (ca. 8%), but the NMR data show no evidence for a non-linear structure. The observation of reduced amide proton temperature dependence coefficients in certain sections of the molecule can, in view of the absence of any other supporting evidence, only be interpreted in terms of local shielding from solvent for sterical reasons (large hydrophobic side-chains).

The conformation of the type III C-telopeptide is mostly extended except for a β-turn ranging from Gly⁸ to Glu¹¹, which is stabilized by a hydrogen-bond between NH of Glu¹¹ and the carbonyl group of Gly⁸. The low temperature coefficient of NH(Glu¹¹) and, in particular, the observation of a medium range NOE between H_α (A⁹) and NH(E¹¹) corroborate the existence of a β-turn in this region. Although spectral overlap prevents a precise conclusion with regard to the type of β-turn present, there is some evidence that it might be type II.     

Increasing incidence of Type 1 diabetes – role for genes?

Background  

The incidence of Type 1 diabetes (T1DM) is increasing fast in many populations. The reasons for this are not known, although an increase in the penetrance of the diabetes-associated alleles, through changes in the environment, might be the most plausible mechanism. After the introduction of insulin treatment in 1930s, an increase in the pool of genetically susceptible individuals has been suggested to contribute to the increase in the incidence of Type 1 diabetes.     

Apparent Involvement of a β1 Type Integrin in Coral Fertilization

Integrins are involved in a wide variety of cell adhesion processes, and have roles in gamete binding and fusion in mammals. Integrins have been also discovered in the scleractinian coral Acropora millepora (Cnidaria: Anthozoa). As a first step toward understanding the molecular basis of fertilization in corals, we examined the effect of polyclonal antisera raised against recombinant coral integrins on gamete interactions in A. millepora. Antiserum raised against integrin βcn1 dramatically decreased the binding of Acropora sperm to eggs and significantly decreased fertilization rates relative to preimmune serum and seawater controls. However, the antiserum against AmIntegrin α1 did not affect significantly either sperm–egg binding or fertilization. One possible explanation for this is that AmIntegrin α1 may preferentially mediate interactions with RGD-containing ligands, whereas mammalian α6 integrin (which is most directly implicated in gamete interactions) preferentially interacts with laminin-related ligands. Our results suggest that β1 type integrins are involved in the fertilization process in Acropora and that some functions of these molecules may have been conserved between corals and mammals. A. Iguchi and L. M. Márquez contributed equally to this work.     

α Cell Function and Gene Expression Are Compromised in Type 1 Diabetes

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How Do Childhood Diagnoses of Type 1 Diabetes Cluster in Time?

Background

Previous studies have indicated that type 1 diabetes may have an infectious origin. The presence of temporal clustering—an irregular temporal distribution of cases—would provide additional evidence that occurrence may be linked with an agent that displays epidemicity. We tested for the presence and form of temporal clustering using population-based data from northeast England.

Materials and Methods

The study analysed data on children aged 0–14 years diagnosed with type 1 diabetes during the period 1990–2007 and resident in a defined geographical region of northeast England (Northumberland, Newcastle upon Tyne, and North Tyneside). Tests for temporal clustering by time of diagnosis were applied using a modified version of the Potthoff-Whittinghill method.

Results

The study analysed 468 cases of children diagnosed with type 1 diabetes. There was highly statistically significant evidence of temporal clustering over periods of a few months and over longer time intervals (p<0.001). The clustering within years did not show a consistent seasonal pattern.

Conclusions

The study adds to the growing body of literature that supports the involvement of infectious agents in the aetiology of type 1 diabetes in children. Specifically it suggests that the precipitating agent or agents involved might be an infection that occurs in “mini-epidemics”.     

Fasting Blood Glucose-A Missing Variable for GFR-Estimation in Type 1 Diabetes?

Objective

Estimation of glomerular filtration rate (eGFR) is one of the current clinical methods for identifying risk for diabetic nephropathy in subjects with type 1 diabetes (T1D). Hyperglycemia is known to influence GFR in T1D and variability in blood glucose at the time of eGFR measurement could introduce bias in eGFR. We hypothesized that simultaneously measured blood glucose would influence eGFR in adults with T1D.

Methods

Longitudinal multivariable mixed-models were employed to investigate the relationships between blood glucose and eGFR by CKD-EPI eGFR_{CYSTATIN C} over 6-years in the Coronary Artery Calcification in Type 1 diabetes (CACTI) study. All subjects with T1D and complete data including blood glucose and cystatin C for at least one of the three visits (n = 616, 554, and 521, respectively) were included in the longitudinal analyses.

Results

In mixed-models adjusting for sex, HbA1c, ACEi/ARB, protein and sodium intake positive associations were observed between simultaneous blood glucose and eGFR_{CYSTATIN C} (β±SE:0.14±0.04 per 10 mg/dL of blood glucose, p<0.0001), and hyperfiltration as a dichotomous outcome (OR: 1.04, 95% CI: 1.01–1.07 per 10 mg/dL of blood glucose, p = 0.02).

Conclusions

In our longitudinal data in subjects with T1D, simultaneous blood glucose has an independent positive effect on eGFR_{CYSTATIN C}. The associations between blood glucose and eGFR_{CYSTATIN C} may bias the accurate detection of early diabetic nephropathy, especially in people with longitudinal variability in blood glucose.     

Decreased Cystathionine-γ-lyase (CSE) Activity in Livers of Type 1 Diabetic Rats and Peripheral Blood Mononuclear Cells (PBMC) of Type 1 Diabetic Patients

The liver plays a major role in the formation of H₂S, a novel signaling molecule. Diabetes is associated with lower blood levels of H₂S. This study investigated the activities of cystathionine-γ-lyase (CSE, the enzyme that catalyzes H₂S formation) in livers of type 1 diabetic (T1D) animals and in peripheral blood mononuclear cells (PBMC) isolated from T1D patients. T1D is associated with both hyperketonemia (acetoacetate and β-hydroxybutyrate) and hyperglycemia. This study also examined the role of hyperglycemia and hyperketonemia per se in decreased CSE activity using U937 monocytes and PBMC isolated from healthy subjects. Livers from streptozotocin-treated T1D rats demonstrated a significantly higher reactive oxygen species production, lower CSE protein expression and activity, and lower H₂S formation compared with those of controls. Studies with T1D patients showed a decrease in CSE protein expression and activity in PBMC compared with those of age-matched normal subjects. Cell culture studies demonstrated that high glucose (25 mm) and/or acetoacetate (4 mm) increased reactive oxygen species, decreased CSE mRNA expression, protein expression, and enzymatic activity, and reduced H₂S levels; however, β-hydroxybutyrate treatment had no effect. A similar effect, which was also observed in PBMC treated with high glucose alone or along with acetoacetate, was prevented by vitamin D supplementation. Studies with CSE siRNA provide evidence for a relationship between impaired CSE expression and reduced H₂S levels. This study demonstrates for the first time that both hyperglycemia and hyperketonemia mediate a reduction in CSE expression and activity, which can contribute to the impaired H₂S signaling associated with diabetes.     

Recent Evolutionary History of Human Immunodeficiency Virus Type 1 Subtype B—Response

Abstract The year of origin estimated by Lukashov and Goudsmit for HIV-1 subtype B is 1976 (95% CI, 1974–1977); this is significantly different from our prior estimate, 1967 (95% CI, 1960–1971). We review published evidence, which suggests that their estimate is too late.     

Substituted phenyl triazoles as selective inhibitors of 11β-Hydroxysteroid Dehydrogenase Type 1

3-(Phenylcyclobutyl)-1,2,4-triazoles were identified as inhibitors of 11β-Hydroxysteroid Dehydrogenase Type 1 (HSD1). They were shown to be active in the mouse in vivo pharmacodynamic model (PD) for HSD1 but exhibited a potent off-target activation of the Pregnane X Receptor (PXR). SAR studies and synthesis of analogs that led to the discovery of a selective HSD1 inhibitor are described in detail.     

Type 1 Diabetic Serum Interferes with Pancreatic β-cell Ca2+ -Handling

The aim of this study was to clarify the frequency of patients with type 1 diabetes that have serum that increases pancreatic β-cell cytoplasmic free Ca²⁺ concentration, [Ca²⁺]_i, and if such an effect is also present in serum from first-degree relatives. We also studied a possible link between the serum effect and ethnic background as well as presence of autoantibodies. Sera obtained from three different countries were investigated as follows: 82 Swedish Caucasians with newly diagnosed type 1 diabetes, 56 Americans with different duration of type 1 diabetes, 117 American first-degree relatives of type 1 diabetic patients with a mixed ethnic background and 31 Caucasian Finnish children with newly diagnosed type 1 diabetes. Changes in [Ca²⁺]_i , upon depolarization, were measured in β-cells incubated overnight with sera from type 1 diabetic patients, first-degree relatives or healthy controls. Our data show that there is a group constituting approximately 30% of type 1 diabetic patients of different gender, age, ethnic background and duration of the disease, as well as first-degree relatives of type 1 diabetic patients, that have sera that interfere with pancreatic β-cell Ca²⁺-handling. This effect on β-cell [Ca²⁺]_i could not be correlated to the presence of autoantibodies. In a defined subgroup of patients with type 1 diabetes and first-degree relatives a defect Ca²⁺-handling may aggravate development of β-cell destruction.     

Decreased GAD(65) -specific Th1/Tc1 phenotype in children with Type 1 diabetes treated with GAD-alum

Diabet. Med. 29, 1272-1278 (2012) ABSTRACT: Aim The balance between T helper cell subsets is an important regulator of the immune system and is often examined after immune therapies. We aimed to study the immunomodulatory effect of glutamic acid decarboxylase (GAD) 65 formulated with aluminium hydroxide (GAD-alum) in children with Type?1 diabetes, focusing on chemokines and their receptors. Methods Blood samples were collected from 70 children with Type?1 diabetes included in a phase?II clinical trial with GAD-alum. Expression of CC chemokine receptor?5 (CCR5) and CCR4 was analysed on CD4+ and CD8+ lymphocytes after in vitro stimulation with GAD(65) using flow cytometry, and secretion of the chemokines CCL2, CCL3 and CCL4 was detected in peripheral blood mononuclear cell supernatants with Luminex. Results Expression of Th1-associated CCR5 was down-regulated following antigen challenge, together with an increased CCR4/CCR5 ratio and CCL2 secretion in GAD-alum-treated patients, but not in the placebo group. Conclusion Our results suggest that GAD-alum treatment has induced a favourable immune modulation associated with decreased Th1/Tc1 phenotypes upon antigen re-challenge, which may be of importance for regulating GAD(65) immunity.     

Plasma C-peptide concentration in women with Type 1 diabetes during early and late pregnancy

Diabet. Med. 29, e361-e364 (2012) ABSTRACT: Aims There are previous suggestions of increased C-peptide concentration in women with Type?1 diabetes during pregnancy. Our aim was to re-evaluate the hypothesis of a pregnancy-induced increase by measuring plasma C-peptide concentration in women with stable blood glucose control under standardized fasting and meal-stimulated conditions. Methods Ten women with Type 1 diabetes; median age 31.1?years, median diabetes duration 19?years, median HbA(1c) 52?mmol/mol (6.9%) were admitted to a clinical research facility for two 24-h visits in early (12-16?weeks) and late (28-32?weeks) pregnancy. Women They ate standardized study meals - 80-g carbohydrate dinner, 60-g carbohydrate breakfast, and fasted between meals and overnight. Closed-loop insulin delivery maintained stable and comparable glycaemic conditions. Paired samples for plasma glucose and C-peptide were obtained. Results Plasma glucose levels were comparable in early (median 6.5?mmol/l; interquartile range 5.6-8.6) and late pregnancy (median 7.0?mmol/l; interquartile range 6.1-7.8; P?=?0.72). There was no change in fasting or meal-stimulated plasma C-peptide concentration from early to late pregnancy; mean difference 4.0?pmol/l (95%?CI -6.0 to 7.0; P?=?0.9). Four women had detectable C-peptide; peak (range) early vs. late pregnancy 48.5 (10-115) vs. 40.0?pmol/l (80-105); P?=?0.5, which was weakly associated with plasma glucose; R(2) =?0.15, P?相似文献   

Tissue-Specific Increases in 11β-Hydroxysteroid Dehydrogenase Type 1 in Normal Weight Postmenopausal Women

With age and menopause there is a shift in adipose distribution from gluteo-femoral to abdominal depots in women. Associated with this redistribution of fat are increased risks of type 2 diabetes and cardiovascular disease. Glucocorticoids influence body composition, and 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) which converts inert cortisone to active cortisol is a putative key mediator of metabolic complications in obesity. Increased 11βHSD1 in adipose tissue may contribute to postmenopausal central obesity. We hypothesized that tissue-specific 11βHSD1 gene expression and activity are up-regulated in the older, postmenopausal women compared to young, premenopausal women. Twenty-three pre- and 23 postmenopausal, healthy, normal weight women were recruited. The participants underwent a urine collection, a subcutaneous adipose tissue biopsy and the hepatic 11βHSD1 activity was estimated by the serum cortisol response after an oral dose of cortisone. Urinary (5α-tetrahydrocortisol+5β-tetrahydrocortisol)/tetrahydrocortisone ratios were higher in postmenopausal women versus premenopausal women in luteal phase (P<0.05), indicating an increased whole-body 11βHSD1 activity. Postmenopausal women had higher 11βHSD1 gene expression in subcutaneous fat (P<0.05). Hepatic first pass conversion of oral cortisone to cortisol was also increased in postmenopausal women versus premenopausal women in follicular phase of the menstrual cycle (P<0.01, at 30 min post cortisone ingestion), suggesting higher hepatic 11βHSD1 activity. In conclusion, our results indicate that postmenopausal normal weight women have increased 11βHSD1 activity in adipose tissue and liver. This may contribute to metabolic dysfunctions with menopause and ageing in women.     

Urinary markers of renal inflammation in adolescents with Type 1 diabetes mellitus and normoalbuminuria

Diabet. Med. 29, 1297-1302 (2012) ABSTRACT: Aims Patients with the highest albumin:creatinine ratio within the normal range are at an increased risk for developing microalbuminuria. The mechanistic basis for this is unknown, but may be related to renal inflammation. Our goal was to characterize the urinary excretion of cytokines/chemokines in normoalbuminuric adolescents with Type?1 diabetes to determine whether higher range normoalbuminuria is associated with evidence of renal inflammation. Methods Forty-two urinary cytokines/chemokines were measured in subjects who were screened for the Adolescent Type?1 Diabetes Cardio-Renal Intervention Trial. Urinary cytokines/chemokines were compared across low (n?=?50), middle (n?=?50) or high (n?=?50) albumin:creatinine ratio tertile groups. Results At baseline, participants in the upper tertile were younger and had shorter diabetes duration compared with the other groups. Other clinical characteristics were similar. Urinary levels of interleukin?6, interleukin?8, platelet-derived growth factor-AA and RANTES differed across albumin:creatinine ratio tertiles, with higher values in patients in the middle and high tertiles compared with the lower tertile (ANCOVA P?≤?0.01). Conclusions Within the normal albumin:creatinine ratio range, higher urinary albumin excretion is associated with elevated urinary levels of inflammatory markers. Ultimately, this may provide mechanistic insights into disease pathophysiology and stratify the risk of nephropathy in Type?1 diabetes.     

How to Dig Deeper? Improved Enrichment Methods for Mucin Core-1 Type Glycopeptides

Two different workflows were tested in order to develop methods that provide deeper insight into the secreted O-glycoproteome. Bovine serum samples were subjected to lectin affinity-chromatography both at the protein- and peptide-level in order to selectively isolate glycopeptides with the most common, mucin core-1 sugar. This enrichment step was implemented with either protein-level mixed-bed ion-exchange chromatography or with peptide-level electrostatic repulsion hydrophilic interaction chromatography. Both methods led to at least 65% of the identified products being glycopeptides, in comparison to ≈ 25% without the additional chromatography steps [Darula, Z., and Medzihradszky, K. F. (2009) Affinity enrichment and characterization of mucin core-1 type glycopeptides from bovine serum. Mol. Cell. Proteomics 8, 2515-2526]. In order to improve not only the isolation but also the characterization of the glycopeptides exoglycosidases were used to eliminate carbohydrate extensions from the directly peptide-bound GalNAc units. Consequent tandem MS analysis of the mixtures using higher-energy collision-dissociation and electron-transfer dissociation led to the identification of 124 glycosylation sites in 51 proteins. While the electron-transfer dissociation data provided the bulk of the information for both modified sequence and modification site assignment, the higher-energy collision-dissociation data frequently yielded confirmation of the peptide identity, and revealed the presence of some core-2 or core-3 oligosaccharides. More than two-thirds of the sites as well as the proteins have never been reported modified.