Mechanisms and early patterns of dyslipidemia in pediatric type 1 and type 2 diabetes

Approaches to Measuring Beta Cell Reserve and Defining Partial Clinical Remission in Paediatric Type 1 Diabetes

CONTEXT

Type 1 diabetes (T1D) results from the autoimmune T-cell mediated destruction of pancreatic beta cells leading to insufficient insulin secretion. At the time of diagnosis of T1D, there is residual beta cell function that declines over the subsequent months to years. Recent interventions have been approved to preserve beta cell function in evolving T1D.

OBJECTIVE

The aim of this review is to summarise the approaches used to assess residual beta cell function in evolving T1D, and to highlight potential future directions.

METHODS

Studies including subjects aged 0 to 18 years were included in this review. The following search terms were used; "(type 1 diabetes) and (partial remission)" and "(type 1 diabetes) and (honeymoon)". References of included studies were reviewed to determine if additional relevant studies were eligible.

RESULTS

There are numerous approaches to quantifying beta cell reserve in evolving T1D. These include c-peptide measurement after a mixed meal or glucagon stimuli, fasting c-peptide, the urinary c-peptide/creatinine ratio, insulin dose-adjusted haemoglobin A1c, and other clinical models to estimate beta cell function. Other biomarkers may have a role, including the proinsulin/c-peptide ratio, cytokines, and microRNA. Studies using thresholds to determine if residual beta cell function is present often differ in values used to define remission.

CONCLUSIONS

As interventions are approved to preserve beta cell function, it will become increasingly necessary to quantify residual beta cell function in research and clinical contexts. In this report, we have highlighted the strengths and limitations of the current approaches.

Immunometabolic biomarkers for partial remission in type 1 diabetes mellitus

Shortly after diagnosis of type 1 diabetes mellitus (T1DM) and initiation of insulin therapy, many patients experience a transient partial remission (PR) phase, also known as the honeymoon phase. This phase presents a potential therapeutic opportunity due to its association with immunoregulatory and β cell-protective mechanisms. However, the lack of biomarkers makes its characterization difficult. In this review, we cover the current literature addressing the discovery of new predictive and monitoring biomarkers that contribute to the understanding of the metabolic, epigenetic, and immunological mechanisms underlying PR. We further discuss how these peripheral biomarkers reflect attempts to arrest β cell autoimmunity and how these can be applied in clinical practice.

Evaluation of the dietary inflammatory index in children and adolescents with type 1 diabetes mellitus and its relationship with nutritional status and metabolic control

OBJECTIVES

The aim of this study was to evaluate the association of the dietary inflammatory index (DII) with the nutritional status and metabolic control of children and adolescents with type 1 diabetes mellitus.

METHODS

This was a cross-sectional study that examined data of children and adolescents ages 7 to 16 y diagnosed with type 1 diabetes mellitus. Dietary intake was assessed using a 24-h dietary recall, from which the DII was calculated. The outcomes were body mass index, lipid profiles (low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol), and glycated hemoglobin. The DII was evaluated in tertiles and in a continuous way. Multiple linear regression was adopted in the analysis, with P < 0.05 considered significant.

RESULTS

Overall, 120 children and adolescents with a mean age of 11.7 (± 2.8) y were included, 53.3% (n = 64) of whom were girls. Excess weight was present in 31.7% participants (n = 38). The average DII was +0.25, ranging from -1.11 to +2.67. Higher values of selenium (P = 0.011), zinc (P = 0.001), fiber (P < 0.001), and other micronutrients were observed in the first tertile of the DII (diet with more antiinflammatory potential). The DII appeared as a predictor of body mass index (P = 0.002; β = 0.23; 95% confidence interval [CI], 0.39-1.75) and non-high-density lipoprotein cholesterol (P = 0.034; β = 0.19; 95% CI, -13.5 to 0.55). There was a tendency for DII to be associated with glycemic control (P = 0.09; β = 0.19; 95% CI, -0.04 to 0.51).

CONCLUSIONS

The inflammatory potential of the diet was associated with increased body mass index and aspects related to metabolic control in children and adolescents with type 1 diabetes mellitus.

The Theory of Hyperlipidemic Memory of Type 1 Diabetes

A literature search was conducted to identify publications addressing the early phases of lipid phenotypes in children and adults with either type 1 diabetes or type 2 diabetes. Medline, EMBASE, and Ovid were searched using the following search terms: clinical remission, partial remission, partial clinical remission, honeymoon phase, C-peptide, type 1 or 2 diabetes, children, pediatric type 1 or 2 diabetes, and paediatrics type 1 or 2 diabetes, adults, adult type 1 or type 2 diabetes. Partial clinical remission (PR) of type 1 diabetes (T1D) is characterized by continued endogenous production of insulin and C-peptide following the diagnosis and the introduction of exogenous insulin therapy. PR is associated with improved glycemic control and reduced prevalence of diabetes complications. The theory of hyperglycemic memory was proposed to explain this concept of improved glycemic outcomes in remitters (those who experienced PR) versus non-remitters (those who did not experience PR). However, this theory is incomplete as it does not explain the dichotomy in early lipid phenotypes in T1D based on PR status, which is an understudied area in diabetology and lipidology. To fill this knowledge gap, we propose the Theory of Hyperlipidemic Memory of T1D. This theory is premised on our 5-year research on early post-diagnostic dichotomy in lipid phenotypes between remitters and non-remitters across the lifespan. It provides a more rigorous explanation for the differences in lifelong atherosclerotic cardiovascular disease (ASCVD) risk between remitters and non-remitters. We conducted 4 clinical studies in pediatric and adult subjects with diabetes mellitus to characterize the particulars of the hyperlipidemic memory. In the first investigation, we explored the impact of the presence or absence of PR on lipid parameters in children and adolescents with T1D. In the second, we investigated whether pubertal maturation influenced our findings in T1D; and whether these findings could be replicated in healthy, non-diabetic children and adolescents. In the third, we leveraged our findings from T1D and controls to investigate the mechanisms of early lipid changes in T2D by comparing the earliest lipid phenotype of subjects with type 2 diabetes (T2D) to those of remitters, non-remitters, and controls. In the fourth, we investigated the impact of PR on the earliest lipid phenotypes in adults with T1D and compared these early lipid data to those of T2D subjects and controls. This body of work across the lifespan in children, adolescents, and adults supports the Theory of Hyperlipidemic Memory. This new theory clarifies why PR largely determines the risks for early-phase dyslipidemia, mid-term microvascular disease risk, and long-term ASCVD risk in subjects with T1D.

Partial Clinical Remission Reduces Lipid-Based Cardiovascular Risk in Adult Patients With Type 1 Diabetes

IMPORTANCE

Risk factors for atherosclerotic cardiovascular disease (ASCVD) are well established in type 2 diabetes (T2D), but not in type 1 diabetes (T1D). The impact of partial clinical remission (PR) on short-term ASCVD risk in T1D is unclear.

AIM

To investigate the impact of PR on the earliest ASCVD risk phenotype in adult T1D using factor analysis to compare the lipid phenotypes of T1D, T2D and controls after stratifying the T1D cohort into remitters and non-remitters.

SUBJECTS AND METHODS

A study of 203 adults subjects consisting of 86 T2D subjects, and 77 T1D subjects stratified into remitters (n=49), and non-remitters (n=28). PR was defined as insulin-dose adjusted HbA1c of ≤9, and obesity as a BMI ≥30 kg/m². Factor analysis was used to stratify the groups by ASCVD risk by factorizing seven lipid parameters (TC, LDL, HDL, non-HDL, TC/HDL, TG, TG/HDL) into 2 orthogonal factors (factor 1: TC*LDL; factor 2: HDL*TG) that explained 90% of the variance in the original seven parameters.

RESULTS

The analysis of individual lipid parameters showed that TC/HDL was similar between the controls and remitters (p=NS) but was significantly higher in the non-remitters compared to the remitters (p=0.026). TG/HDL was equally similar between the controls and remitters (p=NS) but was lower in the remitters compared to the non-remitters (p=0.007). TG was significantly lower in the remitters compared to T2D subjects (p<0.0001) but was similar between T2D subjects and non-remitters (p=NS). Non-HDL was significantly lower in the controls versus non-remitters (p=0.0003) but was similar between the controls and remitters (p=NS). Factor analysis showed that the means of factor 1 and factor 2 composite scores for dyslipidemia increased linearly from the controls, remitters, non-remitters to T2D, p value 0.0042 for factor 1, and <0.0001 for factor 2, with remitters having similar lipid phenotype as controls, while non-remitters were similar to T2D.

CONCLUSIONS

Partial clinical remission of T1D is associated with a favorable early lipid phenotype which could translate to reduced long-term CVD risk in adults.