ObjectiveBody 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.DesignMulticentre longitudinal study carried out at diagnosis and up to 1-year follow-up.MethodsData 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.ResultsIn 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 m2 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).ConclusionsThese 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.
Aims/hypothesis
We investigated whether screening for insulinoma-associated protein (IA-2) beta (IA-2β) autoantibodies (IA-2βA) and zinc transporter-8 (ZnT8) autoantibodies (ZnT8A) improves ...identification of first-degree relatives of type 1 diabetic patients with a high 5-year disease risk, which to date has been based on assays for insulin autoantibodies (IAA), GAD autoantibodies (GADA) and IA-2 autoantibodies (IA-2A).
Methods
IA-2βA and ZnT8A (using a ZnT8 carboxy-terminal hybrid construct, CW-CR, carrying 325Arg and 325Trp) were determined by radiobinding assay in 409 IAA
+
, GADA
+
and/or IA-2A
+
siblings or offspring (<40 years) of type 1 diabetic patients consecutively recruited by the Belgian Diabetes Registry. The median (interquartile range) age of the first-degree relatives was 12 (6–19) years.
Results
Of the first-degree relatives, 24% were IA-2A
+
(
n
= 97), 14% (
n
= 59) IA-2βA
+
and 20% (
n
= 80) ZnT8A
+
. IA-2βA and ZnT8A were significantly (
p
< 0.001) associated with IA-2A and prediabetes (
n
= 86); in IA-2A
−
first-degree relatives (
n
= 312) the presence of IA-2βA and ZnT8A was associated with an increased progression rate to diabetes (
p
< 0.001). Positivity for IA-2A and/or ZnT8A emerged as the most sensitive combination of two markers to identify first-degree relatives with a 5-year progression rate to diabetes of 45% (survival analysis) and as strongest predictor of diabetes (Cox regression analysis). Omission of first-degree relatives protected by
HLA-DQ
genotypes or maternal diabetes reduced the group to be followed from
n
= 409 to
n
= 246 (40%) with minor loss in the number of prediabetic IA-2A
+
or ZnT8A
+
first-degree relatives identified (
n
= 3).
Conclusions/interpretation
IA-2A
+
and/or ZnT8A
+
first-degree relatives may be the participants of choice in future secondary prevention trials with immunointervention in relatives of type 1 diabetic patients.
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.
Summary
In first‐degree relatives of type 1 diabetic patients, we investigated whether diabetes risk assessment solely based on insulinoma antigen 2 (IA‐2) and zinc transporter 8 (ZnT8) antibody ...status (IA‐2A, respectively, ZnT8A) is as effective as screening for three or four autoantibodies antibodies against insulin (IAA), glutamate decarboxylase 65 kDa (GAD) glutamate decarboxylase autoantibodies (GADA) and IA‐2A with or without ZnT8A in identifying children, adolescents and adults who progress rapidly to diabetes (within 5 years). Antibodies were determined by radiobinding assays during follow‐up of 6444 siblings and offspring aged 0–39 years at inclusion and recruited consecutively by the Belgian Diabetes Registry. We identified 394 persistently IAA+, GADA+, IA‐2A+ and/or ZnT8A+ relatives (6·1%). After a median follow‐up time of 52 months, 132 relatives developed type 1 diabetes. In each age category tested (0–9, 10–19 and 20–39 years) progression to diabetes was significantly quicker in the presence of IA‐2A and/or ZnT8A than in their joint absence (P < 0·001). Progression rate was age‐independent in IA‐2A+ and/or ZnT8A+ relatives but decreased with age if only GADA and/or IAA were present (P = 0·008). In the age group mainly considered for immune interventions until now (10–39 years), screening for IA‐2A and ZnT8A alone identified 78% of the rapid progressors (versus 75% if positive for ≥ 2 antibodies among IAA, GADA, IA‐2A and ZnT8A or versus 62% without testing for ZnT8A). Screening for IA‐2A and ZnT8A alone allows identification of the majority of rapidly progressing prediabetic siblings and offspring regardless of age and is more cost‐effective to select participants for intervention trials than conventional screening.
Aims
Specific patterns in incidence may reveal environmental explanations for type 1 diabetes incidence. We aimed to study type 1 diabetes incidence in European childhood populations to assess ...whether an increase could be attributed to either period or cohort effects.
Methods
Nineteen EURODIAB centres provided single year incidence data for ages 0–14 in the 25-year period 1989–2013. Case counts and person years were classified by age, period and cohort (APC) in 1-year classes. APC Poisson regression models of rates were fitted using restricted cubic splines for age, period and cohort per centre and sex. Joint models were fitted for all centres and sexes, to find a parsimonious model.
Results
A total of 57,487 cases were included. In ten and seven of the 19 centres the APC models showed evidence of nonlinear cohort effects or period effects, respectively, in one or both sexes and indications of sex-specific age effects. Models showed a positive linear increase ranging from approximately 0.6 to 6.6%/year. Centres with low incidence rates showed the highest overall increase. A final joint model showed incidence peak at age 11.6 and 12.6 for girls and boys, respectively, and the rate-ratio was according to sex below 1 in ages 5–12.
Conclusion
There was reasonable evidence for similar age-specific type 1 diabetes incidence rates across the EURODIAB population and peaks at a younger age for girls than boys. Cohort effects showed nonlinearity but varied between centres and the model did not contribute convincingly to identification of environmental causes of the increase.
Cardiac depression in severe sepsis and septic shock is characterized by left ventricular (LV) failure. To date, it is unclear whether clinically unrecognized myocardial cell injury accompanies, ...causes, or results from this decreased cardiac performance. We therefore studied the relationship between cardiac troponin I (cTnI) and T (cTnT) and LV dysfunction in early septic shock.
Forty-six patients were consecutively enrolled, fluid-resuscitated, and treated with catecholamines. Cardiac markers were measured at study entry and after 24 and 48 h. LV function was assessed by two-dimensional transesophageal echocardiography.
Increased plasma concentrations of cTnI (>/=0.4 microgram/L) and cTnT (>/=0.1 microgram/L) were found in 50% and 36%, respectively, of the patients at one or more time points. cTnI and cTnT were significantly correlated (r = 0.847; P <0.0001). Compared with cTnI-negative patients, cTnI-positive subjects were older, presented higher Acute Physiology and Chronic Health Evaluation II scores at diagnosis, and tended to have a worse survival rate and a more frequent history of arterial hypertension or previous myocardial infarction. In contrast, the two groups did not differ in type of infection or pathogen, or in dose and type of catecholamine administered. Continuous electrocardiographic monitoring in all patients and autopsy in 12 nonsurvivors did not disclose the occurrence of acute ischemia during the first 48 h of observation. LV dysfunction was strongly associated with cTnI positivity (78% vs 9% in cTnI-negative patients; P <0.001). In multiple regression analysis, both cTnI and cTnT were exclusively associated with LV dysfunction (P <0.0001).
These findings suggest that in septic shock, clinically unrecognized myocardial cell injury is a marker of LV dysfunction. The latter condition tends to occur more often in severely ill older patients with underlying cardiovascular disease. Further studies are needed to determine the extent to which myocardial damage is a cause or a consequence of LV dysfunction.
Aims/hypothesis
Secondary type 1 diabetes prevention trials require selection of participants with impending diabetes.
HLA-A
and -
B
alleles have been reported to promote disease progression. We ...investigated whether typing for
HLA-B*18
and
-B*39
may complement screening for
HLA-DQ8
,
-DQ2
and
-A*24
and autoantibodies (Abs) against islet antigen-2 (IA-2) and zinc transporter 8 (ZnT8) for predicting rapid progression to hyperglycaemia.
Methods
A registry-based group of 288 persistently autoantibody-positive (Ab
+
) offspring/siblings (aged 0–39 years) of known patients (Ab
+
against insulin, GAD, IA-2 and/or ZnT8) were typed for
HLA-DQ
, -
A
and -
B
and monitored from the first Ab
+
sample for development of diabetes within 5 years.
Results
Unlike
HLA-B*39
,
HLA-B*18
was associated with accelerated disease progression, but only in
HLA-DQ2
carriers (
p
< 0.006). In contrast,
HLA-A*24
promoted progression preferentially in the presence of
HLA-DQ8
(
p
< 0.002). In
HLA-DQ2
- and/or
HLA-DQ8
-positive relatives (
n
= 246),
HLA-B*18
predicted impending diabetes (
p
= 0.015) in addition to
HLA-A*24
,
HLA-DQ2/DQ8
and positivity for IA-2A or ZnT8A (
p
≤ 0.004).
HLA-B*18
interacted significantly with
HLA-DQ2/DQ8
and
HLA-A*24
in the presence of IA-2 and/or ZnT8 autoantibodies (
p
≤ 0.009). Additional testing for
HLA-B*18
and
-A*24
significantly improved screening sensitivity for rapid progressors, from 38% to 53%, among relatives at high Ab-inferred risk carrying at least one genetic risk factor. Screening for
HLA-B*18
increased sensitivity for progressors, from 17% to 28%, among individuals carrying ≥3 risk markers conferring >85% 5 year risk.
Conclusions/interpretation
These results reinforce the importance of HLA class I alleles in disease progression and quantify their added value for preparing prevention trials.
There is a clinical need for plasma tests for real-time detection of beta cell destruction, as surrogate endpoint in islet transplantation and immunoprevention trials in type 1 diabetes. This study ...reports on the use of label-free LC-MS/MS proteomics for bottom-up selection of candidate biomarkers. Ubiquitin COOH-terminal hydrolase 1 (UCHL1) was identified as abundant protein in rat and human beta cells, showing promising beta cell-selectivity, and was selected for further validation in standardized toxicity models. In vitro, H2O2-induced necrosis of INS-1 cells and human islets resulted in intracellular UCHL1 depletion and its extracellular discharge. In vivo, streptozotocin progressively depleted UCHL1 from islet cores and in 50% of animals, an associated plasma UCHL1 surge was detected preceding the GAD65 peak. UCHL1 was cleared with a half-life of 20min. Whole-body dynamic planar imaging of 99m-Technetium-labeled UCHL1 indicated a rapid UCHL1 uptake in the liver and spleen, followed by urinary excretion of mainly proteolytic UCHL1 fragments. We conclude that LC-MS/MS proteomics is a useful tool to prioritize biomarkers for beta cell injury with promising molar abundance. Despite its consistent UCHL1 discharge by damaged beta cells in vitro, its in vivo use might be restrained by its rapid elimination from plasma.
Our bottom-up LC-MS/MS proteomics represents a pragmatic approach to identify protein-type biomarkers of pancreatic beta cell injury. UCHL1 successfully passed sequential validation steps of beta cell-selectivity, antigenicity and toxic discharge in vitro. Whole-body dynamic planar imaging of radiolabeled recombinant UCHL1 indicated rapid clearance through the liver, spleen and urinary excretion of proteolytic fragments, likely explaining non-consistent detection in vivo. Integration of kinetic biomarker clearance studies in the a priori selection criteria is recommended before engaging in resource-intensive custom development of sensitive immunoassays for clinical translation.
Display omitted
•There is a clinical need for real time biomarkers for ongoing beta cell destruction.•Label-free LC-MS/MS proteomics is valuable to identify abundant biomarker proteins.•In situ analysis confirmed UCHL1 as an abundant highly beta cell selective protein.•In vitro validation confirmed toxic discharge of UCHL1 by rat and human cells.•In vivo validation of UCHL1 is hampered due to inconsistent plasma detection.
We investigated whether random proinsulin levels and proinsulin:C-peptide ratio (PI:C) complement immune and genetic markers for identifying relatives at high risk of type 1 diabetes.
During an ...initial sampling, random glycaemia, proinsulin, PI:C and HLA DQ genotype were determined in 561 non-diabetic first-degree relatives who had been positive for islet autoantibodies on one or more occasions and in 561 age- and sex-matched persistently antibody-negative relatives.
During follow-up (median 62 months), 46 relatives with antibodies at entry developed type 1 diabetes. At baseline, antibody-positive relatives (n=338) had higher PI:C values (p<0.001) than antibody-negative subjects with (n=223) or subjects without (n=561) later seroconversion. Proinsulin and PI:C were graded according to risk of diabetes as expressed by positivity for (multiple) antibodies or IA-2 antibodies, especially in persons carrying the high-risk HLA DQ2/DQ8 genotype and in prediabetic relatives. In the presence of multiple or IA-2 antibodies, a PI:C ratio exceeding percentile 66 of all antibody-negative relatives at entry (n=784) conferred a 5-year diabetes risk of 50% and 68%, respectively (p<0.001 vs 13% for same antibody status with PI:C<percentile 66). Cox regression analysis confirmed random PI:C as an independent predictor of the risk of diabetes (p< or =0.001).
Random proinsulin and PI:C represent dynamic markers of the state of beta cell function that complement immune markers in identifying relatives who are at homogeneously high risk of contracting type 1 diabetes and are therefore eligible for secondary prevention trials.
Abstract Aims We examined whether parenteral regular insulin can prevent diabetes in IA-2 antibody-positive (IA-2A+) relatives of type 1 diabetic patients, using a trial protocol that differed ...substantially from that of the Diabetes Prevention Trial-1. Methods Twenty-five IA-2A+ relatives received regular human insulin twice a day for 36 months, during which time they were followed (median interquartile range; IQR: 47 19–66 months) for glucose tolerance, HbA1c and islet autoantibodies, together with 25 IA-2A+ relatives (observation/control group) who fulfilled the same inclusion criteria, but were observed for 52 27–67 months (P = 0.58). Results Twelve (48%) insulin-treated relatives and 15 (60%) relatives in the control group developed diabetes. There was no difference in diabetes-free survival between the two groups ( P = 0.97). Five-year progression (95% confidence interval) was 44% (25–69) in the insulin-treated group and 49% (29–70) in the observation group. At inclusion, progressors tended to have a higher pro-insulin/C-peptide ratio than non-progressors when measured 2 hours after a standardized glucose load (median IQR: 2.7% 1.8–4.3 vs. 1.6% 1.1–2.1; P = 0.01). No major hypoglycaemic episodes or significant increases in body mass index or diabetes autoantibodies were observed. Conclusion Prophylactic injections of regular human insulin were well tolerated, but failed to prevent type 1 diabetes onset in IA-2A+ relatives.
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