One third of cases of new-onset diabetic ketosis in adults are associated with ketosis-prone type 2 diabetes-A systematic review and meta-analysis

AIMS

Ketosis-prone type 2 diabetes was defined by the World Health Organization in 2019. According to the literature, the diagnosis is based on the presence of ketosis, islet autoantibody negativity and preserved insulin secretion. Our meta-analysis assessed the prevalence and clinical characteristics of ketosis-prone type 2 diabetes among patients hospitalised with diabetic ketoacidosis (DKA) or ketosis.

METHODS

The systematic search was performed in five main databases as of 15 October 2021 without restrictions. We calculated the pooled prevalence of ketosis-prone type 2 diabetes (exposed group) within the diabetic population under examination, patients with ketoacidosis or ketosis, to identify the clinical characteristics, and we compared it to type 1 diabetes (the comparator group). The random effects model provided pooled estimates as prevalence, odds ratio and mean difference (MD) with 95% confidence intervals.

RESULTS

Eleven articles were eligible for meta-analysis, thus incorporating 2010 patients of various ethnic backgrounds. Among patients presenting with DKA or ketosis at the onset of diabetes, 35% (95% CI: 24%-49%) had ketosis-prone type 2 diabetes. These patients were older (MD = 11.55 years; 95% CI: 5.5-17.6) and had a significantly higher body mass index (BMI) (MD = 5.48 kg/m2 ; 95% CI: 3.25-7.72) than those with type 1 diabetes.

CONCLUSIONS

Ketosis-prone type 2 diabetes accounts for one third of DKA or ketosis at the onset of diabetes in adults. These patients are characterised by islet autoantibody negativity and preserved insulin secretion. They are older and have a higher BMI compared with type 1 diabetes. C-peptide and diabetes-related autoantibody measurement is essential to identify this subgroup among patients with ketosis at the onset of diabetes.

BMI is an important driver of β-cell loss in type 1 diabetes upon diagnosis in 10 to 18-year-old children

OBJECTIVE

Body weight-related insulin resistance probably plays a role in progression to type 1 diabetes, but has an uncertain impact following diagnosis. In this study, we investigated whether BMI measured at diagnosis was an independent predictor of C-peptide decline 1-year post-diagnosis.

DESIGN

Multicentre longitudinal study carried out at diagnosis and up to 1-year follow-up.

METHODS

Data on C-peptide were collected from seven diabetes centres in Europe. Patients were grouped according to age at diagnosis (<5 years, n=126; >5 years <10 years, n=295; >10 years <18 years, n=421; >18 years, n=410). Linear regression was used to investigate whether BMI was an independent predictor of change in fasting C-peptide over 1 year. Models were additionally adjusted for baseline insulin dose and HbA1c.

RESULTS

In individuals diagnosed between 0 and 5 years, 5 and 10 years and those diagnosed >18 years, we found no association between BMI and C-peptide decline. In patients aged 10-18 years, higher BMI at baseline was associated with a greater decline in fasting C-peptide over 1 year with a decrease (β 95% CI; P value) of 0.025 (0.010, 0.041) nM/kg per m(2) higher baseline BMI (P=0.001). This association remained significant after adjusting for gender and differences in HbA1c and insulin dose (β=0.026, 95% CI=0.0097, 0.042; P=0.002).

CONCLUSIONS

These observations indicate that increased body weight and increased insulin demand are associated with more rapid disease progression after diagnosis of type 1 diabetes in an age group 10-18 years. This should be considered in studies of β-cell function in type 1 diabetes.

Age-dependent decline of β-cell function in type 1 diabetes after diagnosis: a multi-centre longitudinal study

AIMS

C-peptide secretion is currently the only available clinical biomarker to measure residual β-cell function in type 1 diabetes. However, the natural history of C-peptide decline after diagnosis can vary considerably dependent upon several variables. We investigated the shape of C-peptide decline over time from type 1 diabetes onset in relation to age at diagnosis, haemoglobin A1c (HbA1c) levels and insulin dose.

METHODS

We analysed data from 3929 type 1 diabetes patients recruited from seven European centres representing all age groups at disease onset (childhood, adolescence and adulthood). The influence of the age at onset on β-cell function was investigated in a longitudinal analysis at diagnosis and up to 5-years follow-up.

RESULTS

Fasting C-peptide (FCP) data at diagnosis were available in 3668 patients stratified according to age at diagnosis in four groups (<5 years, n = 344; >5 years < 10 years, n = 668; >10 years < 18 years, n = 991; >18 years, n = 1655). FCP levels were positively correlated with age (p < 0.001); the subsequent decline in FCP over time was log-linear with a greater decline rate in younger age groups (p < 0.0001).

CONCLUSIONS

This study reveals a positive correlation between age at diagnosis of type 1 diabetes and FCP with a more rapid decline of β-cell function in the very young patients. These data can inform the design of clinical trials using C-peptide values as an end-point for the effect of a given treatment.

The type 2 diabetes-associated variant in TCF7L2 is associated with latent autoimmune diabetes in adult Europeans and the gene effect is modified by obesity: a meta-analysis and an individual study

AIMS/HYPOTHESIS

The variants of transcription factor 7-like 2 (TCF7L2) gene have been proposed to be associated with latent autoimmune diabetes in adults (LADA). We sought to confirm the possible association in Europeans and to examine the interaction between one gene variant and clinical data.

METHODS

The TCF7L2 rs7903146 C-to-T polymorphism was genotyped in 211 LADA, 1,297 type 2 diabetic, 545 type 1 diabetic and 1,497 control individuals from Hungary. A meta-analysis of our and previously published studies was performed to evaluate the size and the heterogeneity of the gene effect.

RESULTS

The meta-analysis yielded a significant effect of TCF7L2 T allele (OR 1.28; p < 0.0001) on LADA risk without heterogeneity among Europeans. The T allele conferred equally strong susceptibility to LADA and type 2 diabetes. In the Hungarian dataset, the T allele was associated with LADA and type 2 diabetes, but not with type 1 diabetes. T allele carriers had significantly lower BMI than patients with the CC genotype in the LADA and type 2 diabetes groups (p = 0.0021 and p = 0.0013, respectively). In both diseases, the diabetes risk was significantly higher in the non-overweight than in the overweight BMI category (p = 0.0013 and p < 0.0001, respectively); susceptibility to LADA was increased by 2.84-fold in non-overweight individuals compared with overweight ones.

CONCLUSIONS/INTERPRETATION

The meta-analysis demonstrates that TCF7L2 rs7903146 polymorphism is a population-independent susceptibility locus for LADA in Europeans. The effect size is similar for LADA and type 2 diabetes. The gene effect on diabetes risk may be modulated by BMI, such that the lower the BMI, the higher the gene effect.

Simulation of the temperature increase in human cadaver retina during direct illumination by 150-kHz femtosecond laser pulses

We have developed a two-dimensional computer model to predict the temperature increase of the retina during femtosecond corneal laser flap cutting. Simulating a typical clinical setting for 150-kHz iFS advanced femtosecond laser (0.8- to 1-μJ laser pulse energy and 15-s procedure time at a laser wavelength of 1053 nm), the temperature increase is 0.2°C. Calculated temperature profiles show good agreement with data obtained from ex vivo experiments using human cadaver retina. Simulation results obtained for different commercial femtosecond lasers indicate that during the laser in situ keratomileusis procedure the temperature increase of the retina is insufficient to induce damage.

Association of hypoxia inducible factor-1 alpha gene polymorphism with both type 1 and type 2 diabetes in a Caucasian (Hungarian) sample

Background

Hypoxia inducible factor-1 alpha (HIF-1α) is a transcription factor that plays an important role in neo-vascularisation, embryonic pancreas beta-cell mass development, and beta cell protection. Recently a non synonymous single nucleotide polymorphism (g.C45035T SNP, rs11549465) of HIF-1α gene, resulting in the p.P582S amino acid change has been shown to be associated with type 2 diabetes (T2DM) in a Japanese population. Our aim was to replicate these findings on a Caucasian (Hungarian) population, as well as to study whether this genetic effect is restricted to T2DM or can be expanded to diabetes in general.

Methods

A large Caucasian sample (N = 890) was recruited including 370 T2DM, 166 T1DM and 354 healthy subjects. Genotyping was validated by two independent methods: a restriction fragment analysis (RFLP) and a real time PCR using TaqMan probes. An overestimation of heterozygotes by RFLP was observed as a consequence of a nearby SNP (rs34005929). Therefore genotyping results of the justified TaqMan system were accepted. The measured genotype distribution corresponded to Hardy-Weinberg equilibrium (P = 0.740)

Results

As the TT genotype was extremely rare in the population (0.6% in clinical sample and 2.5% in controls), the genotypes were grouped as T absent (CC) and T present (CT and TT). Genotype-wise analysis showed a significant increase of T present group in controls (24.0%) as compared to patients (16.8%, P = 0.008). This genetic effect was demonstrated in the separated samples of type 1 (15.1%, P = 0.020), and also in type 2 (17.6%, P = 0.032) diabetes. Allele-wise analysis gave identical results showing a higher frequency of the T allele in the control sample (13.3%) than in the clinical sample (8.7%, P = 0.002) with similar results in type 1 (7.8%, P = 0.010) and type 2 (9.1%, P = 0.011) diabetes. The odds ratio for diabetes (either type 1 or 2) was 1.56 in the presence of the C allele.

Conclusion

We confirmed the protective effect of a rare genetic variant of HIF-1α gene against type 2 diabetes in a Caucasian sample. Moreover we demonstrated a genetic contribution of the same polymorphism in type 1 diabetes as well, supporting a possible overlap in pathomechanism for T2DM and a T1DM.

Effect of heat shock protein peptide DiaPep277 on beta-cell function in paediatric and adult patients with recent-onset diabetes mellitus type 1: two prospective, randomized, double-blind phase II trials

BACKGROUND

Aim of this trial was to test whether heat shock protein peptide DiaPep277 treatment in adult and paediatric patients with recent-onset type 1 diabetes (T1D) is safe and whether it can preserve endogenous insulin production.

METHODS

Two studies were performed in a prospective, multicentre, double-blind, placebo-controlled trial. Fifty adult (study p520, aged 16-44 years) and 49 paediatric patients (study p521, 4-15 years) with recent-onset T1D were treated subcutaneously at four different time points with 0.2 mg or 1.0 mg DiaPep277 versus placebo and followed for 18 months. Adult patients were treated with 0.2 mg, 1.0 mg or 2.5 mg DiaPep277 versus placebo. Stimulated C-peptide served as readout for functional beta-cell-mass.

RESULTS

DiaPep277-treatment was not associated with severe side effects. No differences were found in placebo and DiaPep277 treated groups. In adults, a modest trend towards better maintenance of beta-cell function was observed in the 0.2 mg and 1.0 mg group, while there was significant loss of stimulated C-peptide in the placebo and 2.5 mg group. Paediatric patients with low HLA risk showed stable C-peptide levels until 13 months upon treatment with 1 mg DiaPep277. Despite similar stimulated C-peptide levels at baseline, children exhibited a more pronounced loss of beta-cell function over 18 months than adults (p = 0.0003).

CONCLUSION

Administration of DiaPep277 seems safe and may have beneficial effects on C-peptide levels over time in some patients with T1D, but this finding was not accompanied by reduced HbA1c or insulin requirement. Studies with more patients and longer follow-up are needed to further study the effect of DiaPep277.

Glipizide-induced prevention of diabetes and autoimmune events in the BB rat

To determine whether glipizide, a sulfonylurea, can prevent diabetes in the diabetic-prone BB rat model, rats were studied from 35 to 240 days of age. Treated animals received oral glipizide (10 or 100 mg/kg/day) from 35 to 200 days of age, and control rats received oral placebo. From 80 to 135 days of age at both drug doses, glipizide decreased the incidence of diabetes, thus delaying disease onset (P < 0.02). At the higher dose of glipizide, a diabetes preventive effect was observed (P < 0.025). There were no significant differences in body weights between the treated and control groups. At 240 days, i.e. 40 days after stopping glipizide and placebo treatments, diabetes incidence remained stable in the two groups; thus the effect of glipizide persisted after discontinuation of the drug. Serum glucose and insulin levels measured at 90 and 200 days did not reveal differences between the glipizide treated and control groups. To determine whether the sulfonylurea affected autoimmune events, the prevalence and severity of islet inflammation were examined. In glipizide-treated BB rats at 240 days, only 44% of rats had islet inflammation compared to 86% in the control group (P < 0.01). At both 90 and 240 days the severity of islet inflammation was decreased in the glipizide treatment groups compared with the control groups (P < 0.01). These data indicate that glipizide (a) prevents diabetes in the diabetic-prone BB rat strain, (b) decreases the prevalence and severity of islet inflammation even after drug withdrawal and (c) may dampen autoimmune events leading to diabetes onset.

Quantitative phenotypic and functional analyses of islet immune cells before and after diabetes onset in the BB rat

Inflammatory cells invading islets are thought to be mediators of islet destruction in spontaneous autoimmune diabetes mellitus. Thus methods were developed to isolate and characterize in situ islet inflammatory cells from 75-95-day-old prediabetic and diabetic BB rats. Islet inflammatory cells were structurally examined using single- and double-colour flow cytometry. Functional studies consisted of cytolytic assays using normal rat islet target cells and in situ islet or spleen effector cells. Structural data reveal natural killer cells to be the major cell population (70%) of total immune cells present in inflamed islets during prediabetes. At diabetes onset, the natural killer cell population remained at a high level (47%), but an increasing population of T cells (40%) was noted also. Analyses of T-cell subsets before and after diabetes onset revealed CD4+ T cells as predominant (50-55% of total T cells) with double-negative (CD4-CD8-) T cells (25-30%) and CD8+ T cells (15-20%) also present in significant quantities. Activated T cells accounted only for a minority of T cells (< 3%). Functional studies indicate that in situ islet-derived cytolytic effector cells are more potent killers (ten-fold) of normal islet target cells than are splenic effector cells. These data suggest that in situ islet inflammatory cells (a) can be quantitatively studied both structurally and functionally; (b) express structural phenotypes differing substantially from splenic mononuclear cell populations; (c) are considerably more cytolytic than splenic effectors; and (d) should prove informative in determining the most significant autoimmune functional events prior to and during islet beta-cell destruction.

Quantitative analyses comparing all major spleen cell phenotypes in BB and normal rats: autoimmune imbalance and double negative T cells associated with resistant, prone and diabetic animals

The BB rat is a model of spontaneous autoimmune diabetes. To characterize quantitatively all known immune cell subsets involved in disease pathogenesis, FACS analysis of spleen cells was performed in diabetes-prone (DP) and acutely diabetic (D) BB rats and compared with diabetes-resistant (DR) BB and normal Wistar-Furth (WF) strains. We observed increased percentages of splenic NK cells in DP and D animals compared with DR rats using an NK-specific monoclonal antibody. We found increased proportions of splenic macrophages in the T-lymphopenic DP and D rats and low macrophage contents in DR spleens compared with WF spleens. We observed that percentages of the CD4-CD8- T cell receptor alpha/beta+ (double-negative) T cell subset were strikingly increased in the lymphopenic DP and D animals, compared with DR animals. We observed increased percentages of activated splenic CD5+ T cells expressing the IL-2 receptor and MHC class II antigen in DP and D rats compared with DR animals. Our studies suggest that (a) splenic NK cells and macrophages quantitatively appear to be involved in the pathogenesis of diabetes; (b) double-negative T cells escape from the T cell depletion process; (c) a marked increase of activated splenic T cells suggests diabetes is associated with general T cell activation processes; and (d) an altered balance among the different immune cell subsets may in part explain the pathogenesis of diabetes, since marked relative changes are observed when comparing the DR strain to the DP strain in both the prediabetic and diabetic stages.

In situ islet T cell receptor variable region gene usage in the nonobese diabetic mouse

Several features of the genetics and immunopathology of diabetes in the nonobese diabetic (NOD) mouse, which spontaneously develops type I diabetes, are shared with the human disease. Immunohistochemical studies support the concept that T lymphocytes are the major components of inflammatory cells in the pancreatic islets and these cells may play a critical role in the destruction of the beta cells leading to diabetes. Therefore, we examined whether particular TCR-beta variable region genes were utilized by in situ islet T cells at different stages (4 - 5, 7, 14 - 15 and 16 weeks of age) of the disease process. Dot-blot hybridization was performed using RNA prepared from isolated islets, thymus, spleen, peripheral blood leukocytes and axillary lymph nodes of 10 to 15 mice pooled for each data point. Ten different TCR V-beta probes were used for the analyses. Limited usage of islet V-beta genes was observed only at the early prediabetic stage (4 - 5 weeks old) of the disease. At later stages of the disease (7 - 16 weeks old), no preferential usage of TCR genes was observed in the islets compared to those of peripheral lymphoid organs. These data suggest that only certain types of T cells bearing particular TCR V-beta genes may be responsible for initiating and perpetuating infiltration of immune cells into the islets and these particular T cells are only identified at the very early stages of the autoimmune process.

Quantitative and functional analyses of spleen and in situ islet immune cells before and after diabetes onset in the NOD mouse

Cytofluorometric analysis using specific monoclonal antibodies directed against the T cell antigens Thy-1.2, CD4, CD8, CD4V beta(8.1 + 8.2 + 8.3), and the antigen Mac-1 expressed by mature macrophages and NK cells were used to characterize and quantify the phenotypes of (1) unfractionated and Percoll gradient fractionated in situ islet immune cells isolated from prediabetic and diabetic female NOD mouse spleens. We found in prediabetic female mice that the majority (approximately 70%) of the in situ islet immune cells were Thy-1.2 positive T cells. CD4 positive T cells (approximately 40%) were the most abundant phenotype together with double negative T cells (approximately 20%). The percentage of CD8 positive T cells were approximately 10%, and only approximately 4% of the immune cells were Mac-1 positive. The percentages of CD4V beta (8.1 + 8.2 + 8.3) positive and double negative T cells in diabetic spleens were significantly higher in comparison to prediabetic spleens. In C57B1/6J control nondiabetic mice the percentage of double negative T cells in the spleens was significantly 4-fold lower when compared to diabetic NOD spleens. The specific cytolytic activity mediated by in situ islet immune cells against 51Cr-labeled dispersed syngeneic single-cell islet cells at an effector to target ratio of 20 was twenty- to thirty-fold higher than that mediated by prediabetic splenic lymphoid cells. It is concluded that prediabetic NOD mouse in situ islet immune cells are mostly CD4 positive and double negative T cells, and that CD4 and CD8 positive T cells in the intra-islet infiltrate warrants further evaluation as potential effector T cells in target beta-cell destruction.