Prevalence of and Reasons for Discontinuation of Continuous Subcutaneous Insulin Infusion in People with Type 1 Diabetes: A Systematic Review.

The introduction of continuous subcutaneous insulin infusion in clinical care has led to more optimal glycemic and quality-of-life outcomes, compared with multiple daily injections (MDI). Despite this, some insulin pump users revert back to MDI. The aim of this review was to include the most recent rates of insulin pump discontinuation among people with type 1 diabetes and to identify reasons for and factors associated with discontinuation. A systematic literature search was conducted using the Embase.com, MEDLINE (via OVID), PsycINFO, and CINAHL databases. Titles and abstracts of eligible publications were screened, and baseline characteristics of the included studies were extracted, as were variables in the context of insulin pump use. Data were synthesized into themes: indications for insulin pump initiation, persons with type 1 diabetes (PWD)-reported reasons for, and factors associated with insulin pump discontinuation. A total of 826 eligible publications were identified and 67 were included. Discontinuation percentages ranged from 0% to 30% (median 7%). The most frequently mentioned reasons for discontinuation were wear-related issues (e.g., device attached to the body, interference with daily activities, discomfort, affected body image). Related factors included hemoglobin A1c (HbA1c) (17%), issues with following treatment recommendations (14%), age (11%), gender (9%), side effects (7%), and comorbidity- and complication-related factors (6%). Despite many developments in insulin pump technology, discontinuation rates and PWD-reported reasons for and factors associated with insulin pump discontinuation in more recent studies were comparable to earlier reviews/meta-analyses. Continuation of insulin pump treatment depends on a knowledgeable and willing health care provider (HCP) team and a close match with PWDs' wishes and needs.

Fasting and meal-stimulated serum C-peptide in long-standing type 1 diabetes mellitus.

AIMS: This study aims to evaluate the stability of C-peptide over time and to compare fasting C-peptide and C-peptide response after mixed-meal tolerance test (MMTT) at T90 or T120 with C-peptide area under the curve (AUC) in long-standing type 1 diabetes. METHODS: We included 607 type 1 diabetes individuals with diabetes duration >5 years. C-peptide concentrations (ultrasensitive assay) were collected in the fasting state, and in a subpopulation after MMTT (T0, just prior to, T30-T60-T90-T120, 30-120 min after ingestion of mixed-meal) (n = 168). Fasting C-peptide concentrations (in n = 535) at Year 0 and Year 1 were compared. The clinical determinants associated with residual C-peptide secretion and the correspondence of C-peptide at MMTT T90 / T120 and total AUC were assessed. RESULTS: A total of 153 participants (25%) had detectable fasting serum C-peptide (i.e ≥ 3.8 pmol/L). Fasting C-peptide was significantly lower at Year 1 (p < 0.001, effect size = -0.16). Participants with higher fasting C-peptide had a higher age at diagnosis and shorter disease duration and were less frequently insulin pump users. Overall, 109 of 168 (65%) participants had both non-detectable fasting and post-meal serum C-peptide concentrations. The T90 and T120 C-peptide values at MMTT were concordant with total AUC. In 17 (10%) individuals, C-peptide was only detectable at MMTT and not in the fasting state. CONCLUSIONS: Stimulated C-peptide was detectable in an additional 10% of individuals compared with fasting in individuals with >5 years of diabetes duration. T90 and T120 MMTT measurements showed good concordance with the MMTT total AUC. Overall, there was a decrease of C-peptide at 1-year follow-up.

Effects of Peri-Conception and Pregnancy Glycemic Variability on Pregnancy and Perinatal Complications in Type 1 Diabetes: A Pilot Study.

BACKGROUND: Not much is known about the effects of glycemic variability (GV) during the pre- and periconception period on pregnancy/perinatal complications. GV could potentially contribute to identification of high-risk pregnancies in women with type 1 diabetes. METHODS: An explorative retrospective cohort study was conducted between January 2014 and May 2019. Glucose data were retrieved from electronic patient charts. Pre-/periconceptional GV and GV during all three trimesters was expressed as mean glucose, standard deviation (SD), Coefficient of Variation (CV), High Blood Glucose Index (HBGI), Low Blood Glucose Index (LBGI) and Average Daily Risk Range (ADRR). Maternal and neonatal complications were summarized using a composite total complication score. Binary logistic regression analyses were conducted to assess associations between the GV measures and a total complication score>3, a maternal complication score>1 and a neonatal complication score>1. RESULTS: Of 63 eligible women, 29 women (38 pregnancies) were included. Women in the group with a total complication score>3 had a significantly higher ADRR at conception (OR 1.1, CI 1.0-1.2, p=0.048). No statistically significant correlations between complication score and any other GV metric besides the ADRR were found. Although not significant, in the group with a complication score>3, odds ratios>1 were found for SD in trimester 1 (OR 1.6, CI 0.6-4.5, p=0.357) and trimester 2 (OR 1.8, CI 0.5-6.2, p=0.376). CONCLUSIONS: Presence of a positive association between GV and pregnancy and perinatal complications depends on which pregnancy period is assessed and the GV metrics that are used.

Which C-peptide assay do you use? Increasing need for describing C-peptide assay performance.

Many C-peptide assays are commercially available for research and routine use. However, not all assays yield consistent results, especially in the low concentration ranges. We searched the literature describing C-peptide measurements to assess which assays are mainly used in the diabetes research field and if they are specified. Percentages of publications on C-peptide measurements in type 1 diabetes (T1D), type 2 diabetes (T2D) and other forms of diabetes were 32%, 54% and 14%, respectively. In only 54% of the publications the used assay was specified. Information on detection limit, measurement range and variation was provided in 12%, 2% and 11% of publications, respectively. In 22% of all publications no C-peptides concentrations were mentioned. This may be a problem especially for T1D research, where measuring very low levels of C-peptide is becoming increasingly important and concordance between assays is low.

How low is really low? Comparison of two C-peptide assays to establish residual C-peptide production in type 1 diabetes.

INTRODUCTION: C-peptide is an important marker to assess residual insulin production in individuals with type 1 diabetes (T1D). The accuracy and detection limits of C-peptide assays are important to detect C-peptide microsecretion and to reliably observe changes over time in these people. We compared and verified two commercially available assays able to measure C-peptide in the picomolar range. METHODS: The ultrasensitive Mercodia enzyme-linked immunosorbent C-peptide assay (ELISA) was compared with the Beckman immunoradiometric assay (IRMA) for C-peptide, assessing reproducibility (coefficient of variation [CV]), limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ). RESULTS: For both assays within-run and between-run variation were high at the low (around the detection limit) C-peptide concentration range, with CVs of around 40%. LoB values for the ultrasensitive ELISA and the IRMA were 1.3 and 0.16 pmol/L respectively. LoD values were 2.4 and 0.54 pmol/L respectively. LoQ values were 9.7 and 3.8 pmol/L respectively. Only the IRMA met the specifications claimed by the manufacturer. CONCLUSIONS: The IRMA provided the lowest threshold for quantification of serum C-peptide. LoQ of commercially available assays should be established in-house before applying them in research studies and clinical trials in which low C-peptide levels have clinical or scientific relevance.

When Elasticity Affects Drop Coalescence.

The breakup and coalescence of drops are elementary topological transitions in interfacial flows. The breakup of a drop changes dramatically when polymers are added to the fluid. With the strong elongation of the polymers during the process, long threads connecting the two droplets appear prior to their eventual pinch-off. Here, we demonstrate how elasticity affects drop coalescence, the complement of the much studied drop pinch-off. We reveal the emergence of an elastic singularity, characterized by a diverging interface curvature at the point of coalescence. Intriguingly, while the polymers dictate the spatial features of coalescence, they hardly affect the temporal evolution of the bridge. These results are explained using a novel viscoelastic similarity analysis and are relevant for drops created in biofluids, coating sprays, and inkjet printing.

Residual C-peptide secretion and hypoglycemia awareness in people with type 1 diabetes.

INTRODUCTION: This study aimed to assess the association between fasting serum C-peptide levels and the presence of impaired awareness of hypoglycemia (IAH) in people with type 1 diabetes. RESEARCH DESIGN AND METHODS: We performed a cross-sectional study among 509 individuals with type 1 diabetes (diabetes duration 5-65 years). Extensive clinical data and fasting serum C-peptide concentrations were collected and related to the presence or absence of IAH, which was evaluated using the validated Dutch version of the Clarke questionnaire. A multivariable logistic regression model was constructed to investigate the association of C-peptide and other clinical variables with IAH. RESULTS: In 129 (25%) individuals, residual C-peptide secretion was detected, while 75 (15%) individuals reported IAH. The median (IQR) C-peptide concentration among all participants was 0.0 (0.0-3.9) pmol/L. The prevalence of severe hypoglycemia was lower in people with demonstrable C-peptide versus those with absent C-peptide (30% vs 41%, p=0.025). Individuals with IAH were older, had longer diabetes duration, more frequently had macrovascular and microvascular complications, and more often used antihypertensive drugs, antiplatelet agents and cholesterol-lowering medication. There was a strong association between IAH and having a severe hypoglycemia in the preceding year. In multivariable regression analysis, residual C-peptide, either continuously or dichotomous, was associated with lower prevalence of IAH (p=0.040-0.042), while age at diabetes onset (p=0.001), presence of microvascular complications (p=0.003) and body mass index (BMI) (p=0.003) were also independently associated with the presence of IAH. CONCLUSIONS: Higher BMI, the presence of microvascular complications and higher age at diabetes onset were independent risk factors for IAH in people with type 1 diabetes, while residual C-peptide secretion was associated with lower risk of this complication.

Losing Track of Lipids in Children and Adolescents with Type 1 Diabetes: Towards Individualized Patient Care.

AIM: To assess 1) the prevalence of children and adolescents with type 1 diabetes (T1D) changing from low-risk into borderline-high-risk lipid levels or from borderline-high-risk into high-risk lipid levels ('lose track of lipids') and 2) the power of a risk score including the determinants HbA1c, body mass index (BMI), gender, age, diabetes duration and ethnicity in predicting which patients lose track of lipids. METHODS: 651 children and adolescents with T1D were included in this longitudinal retrospective cohort study. Lipid dynamics and the impact of the risk score on losing track of lipids were evaluated. Kaplan-Meier analysis was used to estimate screening intervals. RESULTS: 31-43% percent of the patients had lost track of one or more lipids at the next lipid measurement. This happened more frequently in patients with a low-risk lipid level at start. Depending on the lipid parameter, 5% of patients with low-risk lipid levels lost track of lipids after 13-23 months. The risk score based on concomitant information on the determinants was moderately able to predict which patients would lose track of lipids on the short term. CONCLUSIONS: A considerable number of children and adolescents with T1D loses track of lipids and does so within a 2-year screening interval. The predictive power of a risk score including age, BMI, gender, HbA1c, diabetes duration and ethnicity is only moderate. Future research should focus on another approach to the determinants used in this study or other determinants predictive of losing track of lipids on the short term.

Microarray-based identification of age-dependent differences in gene expression of human dermal fibroblasts.

Senescence is thought to play an important role in the progressive age-related decline in tissue integrity and concomitant diseases, but not much is known about the complex interplay between upstream regulators and downstream effectors. We profiled whole genome gene expression of non-stressed and rotenone-stressed human fibroblast strains from young and oldest old subjects, and measured senescence associated ß-gal activity. Microarray results identified gene sets involved in carbohydrate metabolism, Wnt/ß-catenin signaling, the cell cycle, glutamate signaling, RNA-processing and mitochondrial function as being differentially regulated with chronological age. The most significantly differentially regulated mRNA corresponded to the p16 gene. p16 was then investigated using qPCR, Western blotting and immunocytochemistry. In conclusion, we have identified cellular pathways that are differentially expressed between fibroblast strains from young and old subjects.

Human in vivo longevity is reflected in vitro by differential metabolism as measured by (1)H-NMR profiling of cell culture supernatants.

The offspring of nonagenarian siblings suffer less from age related conditions and have a lower risk of mortality compared to their partners. Fibroblast strains derived from such offspring in middle age show different in vitro responses to stress, more stress-induced apoptosis and less senescence when compared to strains of their partners. Aiming to find differences in cellular metabolism in vitro between these fibroblast strains, cell culture supernatants collected at 24 hours and five days were analysed using (1)H nuclear magnetic resonance (NMR)-based metabolic footprinting. Between 24 hours and five days of incubation, supernatants of all fibroblast strains showed decreased levels of glucose, pyruvate, alanine-glutamine (ala-gln), valine, leucine, isoleucine, serine and lysine and increased levels of glutamine, alanine, lactate and pyroglutamic acid. Strains from offspring and their partners were compared using a partial least squares-discriminant analysis (PLS-DA) model based on the data of the five-day time point. The ala-gln and glucose consumption were higher for fibroblast strains derived from offspring when compared to strains of their partners. Also, production of glutamine, alanine, lactate and pyroglutamic acid was found to be higher for fibroblast strains derived from offspring. In conclusion, differences in NMR-based metabolic profiles of human cells in vitro reflect the propensity for human longevity of the subjects from whom these were derived.

Chronic inhibition of the respiratory chain in human fibroblast cultures: differential responses related to subject chronological and biological age.

Respiratory chain function becomes less efficient with age resulting in increased levels of damaging reactive oxygen species. We compared rotenone-exposed fibroblast strains from young and old subjects and from offspring of nonagenarian siblings and the partners of the offspring. Rotenone increased reactive oxygen species levels, inhibited growth rate, and increased telomere shortening (all p < .05). Non-stressed strains from young subjects showed lower reactive oxygen species levels (p = .031) and higher growth rates (p = .002) than strains from old subjects. Stressed strains from young subjects showed smaller increases in reactive oxygen species levels (p = .014) and larger decreases in growth rate (p < .001) than strains from old subjects. Telomere-shortening rates were not different between groups. Stress-induced decreases in growth rate were larger in strains from offspring than from partners (p = .05). Strains from young and old subjects are differentially affected by chronic inhibition of the respiratory chain. Changed growth rates in strains from offspring resemble those from strains from young subjects.

Relation between maximum replicative capacity and oxidative stress-induced responses in human skin fibroblasts in vitro.

Cellular senescence, an important factor in ageing phenotypes, can be induced by replicative exhaustion or by stress. We investigated the relation between maximum replicative capacity, telomere length, stress-induced cellular senescence, and apoptosis/cell death in human primary fibroblast strains obtained from nonagenarians of the Leiden 85-plus Study. Fibroblast strains were cultured until replicative senescence and stressed with rotenone at low passage. Telomere length, senescence-associated-ß-galactosidase activity, sub-G1 content, and Annexin-V/PI positivity were measured in nonstressed and stressed conditions. Fibroblast strains with a higher replicative capacity had longer telomeres (p = .054). In nonstressed conditions, replicative capacity was not associated with ß-gal activity (p = .07) and negatively with sub-G1 (p = .008). In rotenone-stressed conditions, replicative capacity was negatively associated with ß-gal activity (p = .034) and positively with sub-G1 (p = .07). Summarizing, fibroblast strains with a higher maximum replicative capacity have longer telomeres, are less prone to go into stress-induced cellular senescence, and more prone to die after stress.

Rapid flow cytometric method for measuring senescence associated beta-galactosidase activity in human fibroblasts.

Senescence associated-beta-galactosidase (SA-beta-gal) activity is a widely used marker for cellular senenescence. SA-beta-gal activity is routinely detected cytochemically, manually discriminating negative from positive cells. This method is time-consuming, subjective and therefore prone to operator-error. We aimed to optimize a flow cytometric method described by other workers using endothelial cells to better differentiate between populations of fibroblasts in degrees of SA-beta-gal activity. Skin fibroblasts were isolated from young (mean age +/- SD: 25.5 +/- 1.8) and very old (age 90.2 +/- 0.3) subjects. Different pH modulators were tested for toxicity. To induce stress-induced senescence, fibroblasts were exposed to rotenone. Senescence was assessed measuring SA-beta-gal activity by cytochemistry (X-gal) and by flow cytometry (C(12)FDG). The pH modulator Bafilomycin A1 (Baf A1) was found to be least toxic for fibroblasts and to differentiate best between nonstressed and stressed fibroblast populations. Under nonstressed conditions, fibroblasts from very old subjects showed higher SA-beta-gal activity than fibroblasts from young subjects. This difference was found for both the flow cytometric and cytochemical methods (P = 0.013 and P = 0.056 respectively). Under stress-induced conditions the flow cytometric method but not the cytochemical method revealed significant higher SA-beta-gal activity in fibroblasts from very old compared to young subjects (P = 0.004 and P = 0.635 respectively). We found the modified flow cytometric method measuring SA-beta-gal activity superior in discriminating between degrees of senescence in different populations of fibroblasts.

Stress-induced responses of human skin fibroblasts in vitro reflect human longevity.

Unlike various model organisms, cellular responses to stress have not been related to human longevity. We investigated cellular responses to stress in skin fibroblasts that were isolated from young and very old subjects, and from offspring of nonagenarian siblings and their partners, representatives of the general population. Fibroblasts were exposed to rotenone and hyperglycemia and assessed for senescence-associated beta-galactosidase (SA-beta-gal) activity by flow cytometry. Apoptosis/cell death was measured with the Annexin-V/PI assay and cell-cycle analysis (Sub-G1 content) and growth potential was determined by the colony formation assay. Compared with fibroblasts from young subjects, baseline SA-beta-gal activity was higher in fibroblasts from old subjects (P = 0.004) as were stress-induced increases (rotenone: P < 0.001, hyperglycemia: P = 0.027). For measures of apoptosis/cell death, fibroblasts from old subjects showed higher baseline levels (Annexin V+/PI+ cells: P = 0.040, Sub-G1: P = 0.014) and lower stress-induced increases (Sub-G1: P = 0.018) than fibroblasts from young subjects. Numbers and total size of colonies under nonstressed conditions were higher for fibroblasts from young subjects (P = 0.017 and 0.006, respectively). Baseline levels of SA-beta-gal activity and apoptosis/cell death were not different between fibroblasts from offspring and partner. Stress-induced increases were lower for SA-beta-gal activity (rotenone: P = 0.064, hyperglycemia: P < 0.001) and higher for apoptosis/cell death (Annexin V+/PI- cells: P = 0.041, Annexin V+/PI+ cells: P = 0.008). Numbers and total size of colonies under nonstressed conditions were higher for fibroblasts from offspring (P = 0.001 and 0.024, respectively) whereas rotenone-induced decreases were lower (P = 0.008 and 0.004, respectively). These data provide strong support for the hypothesis that in vitro cellular responses to stress reflect the propensity for human longevity.

Protection by food-derived antioxidants from UV-A1-induced photodamage, measured using living skin equivalents.

In a study of biomarkers of ultraviolet-A1 radiation (UV-A1)-induced skin damage, living skin equivalent cultures (LSE) were treated with the antioxidants hesperetin and quercetin-3-glucoside and irradiated with 25 or 50 J/cm2 UV-A1. Changes in the following biomarkers were measured; Interleukin 1-alpha (IL-1alpha), Heme Oxygenase-1 (HO-1), TdT-mediated dUTP nick end labeling (TUNEL) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). IL-1alpha and HO-1 were analyzed by real-time PCR, Western blot, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. TUNEL and 8-OHdG were determined by (immuno)histochemical techniques. Sections were stained with hematoxylin and eosin (H&E). UV-A1 induced keratinocyte and fibroblast vacuolation and nuclear pyknosis, intense TUNEL staining of fibroblasts and increased staining of cells and nuclei for 8-OHdG. Lesser or marginal increases in intensity followed staining for HO-1 and IL-1alpha. The IL-1alpha increase was confirmed by ELISA assays of the medium supernatants. Hesperetin and quercetin-3-glucoside reduced changes in H&E, 8-OHdG, TUNEL and IL-1alpha. Quercetin-3-glucoside reduced the amount of IL-1alpha in LSE media. These observations support the use of the selected biomarkers to monitor UV-A1 damage and provide evidence that dietary ingredients could reduce ultraviolet-A radiation-induced damage.