The importance of anti-insulin antibody in patients with type 1 diabetes mellitus treated with continuous subcutaneous insulin infusion or multiple daily insulin injections therapy

Recurrent Hypoglycemia Due to a High Titer of Insulin Antibody in Response to Exogenous Insulin Administration in Two Cases of Type 1 Diabetes

In the first case, a 60-year-old man who was using continuous subcutaneous insulin infusion (CSII), developed recurrent hypoglycemia due to insulin antibodies. This is the first report of such a case using CSII. In the second case, a 70-year-old man was follow-up case who developed hypoglycemia while using human insulin. In both cases, the hypoglycemia subsided after switching to multiple daily insulin injection and/or insulin preparation. The results of Scatchard analyses of the two cases were similar to those of cases of insulin autoimmune syndrome (IAS) that improved after recovery from hypoglycemia.The clinical characteristics and Scatchard analysis data were essentially the same as those for IAS, except for the presence of insulin administration.

Clinical and Laboratory Aspects of Insulin Autoantibody-Mediated Glycaemic Dysregulation and Hyperinsulinaemic Hypoglycaemia: Insulin Autoimmune Syndrome and Exogenous Insulin Antibody Syndrome

Autoimmune glycaemic dysregulation and hyperinsulinaemic hypoglycaemia mediated by insulin autoantibodies is an increasingly recognised but controversial phenomenon described in both exogenous insulin naïve (insulin autoimmune syndrome) and exposed (exogenous insulin antibody syndrome) individuals. There has been a significant proliferation of case reports, clinical studies and reviews in the medical literature in recent years which have collectively highlighted the discrepancy between experts in the field with regard to the nomenclature, definition, proposed pathophysiology, as well as the clinical and biochemical diagnostic criteria associated with the condition. The essential characteristics of the condition are glycaemic dysregulation manifesting as episodes of hyperglycaemia and unpredictable hyperinsulinaemic hypoglycaemia associated with high titres of endogenous antibodies to insulin. Although the hypoglycaemia is often life-threatening and initiation of targeted therapies critical, the diagnosis is often delayed and attributable to various factors including: the fact that existence of the condition is not universally accepted; the need to exclude surreptitious causes of hypoglycaemia; the diverse and often complex nature of the glycaemic dysregulation; and the challenge of diagnostic confirmation. Once confirmed, the available therapeutic options are expansive and the reported responses to these therapies have been variable. This review will focus on our evolving understanding, and the associated diagnostic challenges - both clinical and laboratory - of this complex condition.

Biochemical, serological, and genetic aspects related to gene HLA-DQB1 and its association with type 1 diabetes mellitus (T1DM)

Background

Type 1 Diabetes Mellitus (T1DM) is the autoimmune disorder of destruction of β cells of pancreas, creating insulin deficiency condition, which leads to hyperglycemia, polyuria, polydipsia, ketoacidosis, and other metabolic disorder especially in children. Different genetic aspects and environmental factors are involved in pathophysiology of the disease. About 20 genes are associated with this disease in which the most common is the different combination of haplotype DRB1‐DQA1‐DQB1 present at HLA gene. At HLA‐DQB1, there are some SNPs which are associated with T1DM. In T1DM, there are number of biochemical, serological parameters which show some abnormalities leading to some complications.

Methods

Samples were subjected to all biochemical and serological techniques to get the measurement of concentration of glucose, lipid profile (cholesterol, triglycerides, and HDL and LDL cholesterol), urea, creatinine, albumin, insulin, anti‐insulin antibodies, C‐peptides, and leptin. All these values were compared with controls values and statistical analysis was also done on these values. At molecular level, two primers set which were allele specific at HLA‐DQB1, were used to amplify the SNPs, homozygous and heterozygous conditions were stated.

Results

PCR results for the studied population showed that most of samples have heterozygous condition for these SNPs of this allele specific region on HLA‐DQB1. Very few of them have homozygous state for it. Even in the control sample have the same conditions.

Conclusion

In Pakistan, there is dire need of studies about SNPs and haplotypes related to HLA‐DQB1 which show association with T1DM.

Association of Higher Circulating Insulin Antibody with Increased Mean Amplitude Glycemic Excursion in Patients with Type 2 Diabetes Mellitus: A Cross-Sectional, Retrospective Case-Control Study

Insulin antibody (IA) may potentially affect a patient's glycemic control due to its variability in both binding and/or releasing insulin. However, the association between IA titer and daily glycemic variability (GV) is still unknown. We thus performed this cross-sectional, retrospective case-control study to assess the relationship between IA titer and mean amplitude glycemic excursion (MAGE) in type 2 diabetes mellitus (T2DM) patients using a continuous glucose monitoring (CGM) system. We recruited 100 eligible patients (IA > 5%, IA positive) and divided them into two groups-a low (L) group and a high (H) group-based on their IA titer. The control (C) group consisted of 47 patients (IA ≤ 5%, IA negative) matched for age, BMI, gender, and glycosylated hemoglobin A1c (HbA1c). The CGM determined the GV of enrolled patients. The primary outcome was the relationship between the IA titer and the MAGE, and the secondary outcome was the differences of GV among the three groups. We found that patients in the H group had higher levels of blood glucose fluctuation parameters than those in the L and C groups. The Ln(IA) was positively correlated with Ln(MAGE) even after adjusting for age, gender, BMI, HbA1c, and fasting and postprandial C-peptide(r = 0.423, p < 0.001). Multiple linear stepwise regression analysis revealed that Ln(IA) was an independent factor of Ln(MAGE) (beta = 0.405, p < 0.001). In conclusion, the higher circulating IA titer was associated with increased MAGE in T2DM patients, indicating that those patients with elevated IA titer should receive GV assessment and individualized treatment.

Therapeutic plasma exchange normalizes insulin-mediated response in a child with type 1 diabetes and insulin autoimmune syndrome

BACKGROUND

Insulin autoimmune syndrome (IAS), characterized by glycemic dysregulation and life-threatening hypoglycemia, can occur in patients with type 1 diabetes (T1D). Diagnostic confirmation is complex but important in order to ensure timely initiation of definitive therapy.

AIMS

We aimed to quantitate the degree of immunoglobulin-insulin complex (IIC) formation and its effects on glycemic control in a patient with T1D and IAS compared with T1D and non-T1D controls and before and after therapeutic plasma exchange (TPE).

MATERIALS & METHODS

The prospective descriptive study was conducted between June 2015 and December 2015 in a quaternary children's hospital in Brisbane, Australia. Percent Free "Immunoreactive" Insulin (%FII) as assessed by polyethylene glycol precipitation studies and its relationship to plasma glucose and serum insulin concentration.

RESULTS

Samples from the patient with T1D and IAS demonstrated lower mean %FII compared to T1D (23.8 ± 2.0 vs 52.0 ± 6.7; P < .0001) and non-T1D (23.8 ± 2.0 vs 102.9 ± 2.7; P < .0001) controls. This was associated with loss of glycemic predictability and frequent severe hypoglycemia. TPE increased %FII (23.8 ± 2.0 before TPE vs 83.6 ± 2.5 after TPE, P < .0001) and reestablished plasma glucose responsiveness to exogenous insulin.

DISCUSSION

IAS should be considered in T1D patients with unexplained glycemic instability and hypoglycemia. The laboratory plays an integral diagnostic role.

CONCLUSION

TPE is an effective method for removing IICs and normalizing insulin-mediated glucose responses.

Comparison of human insulin and insulin analogues on hypoglycaemia and metabolic variability in type 1 diabetes using standardized measurements (HYPO score and Lability Index)

To evaluate whether treatment with insulin analogues is associated with a lower risk of hypoglycaemia (HYPO score) and less glycaemic variability (Lability Index) than treatment with human insulin in patients with type 1 diabetes. In a 6-month prospective, open-labelled trial, we randomized 47 patients treated with human insulin to receive treatment with human insulin (n = 21) or insulin analogues (n = 26). HYPO score, Lability Index (LI), and hypoglycaemic episode characteristics were assessed at baseline and at the end of follow-up. A 72-h, continuous glucose monitoring was performed at the end in a subgroup of patients. Groups were compared with nonparametric tests. Significance was defined as P < 0.05. HYPO score (71.5 [36.0-162] vs. 260 [52.0-676], P < 0.05), nocturnal hypoglycaemia (0.4 vs. 1.4 events/patient/4-week, P < 0.05), and <2.5 mmol/l hypoglycaemic events were lower in insulin analogue group after 6 months. There was a trend towards a lower LI in insulin analogue group (74.3 [51.3-133] vs. 123 [76.4-171] mmol/l(2)/h week(-1), P = 0.064). HbA1c and insulin dose were comparable between groups. In type 1 diabetes, insulin analogues were associated with a lower hypoglycaemic risk and a trend towards reduced glycaemic variability compared with human insulin. These effects occurred despite comparable metabolic control.

Stabilization of bovine insulin against agitation-induced aggregation using RNA aptamers

Stabilization of monomeric insulin is a primary requirement for preserving the efficacy of the final formulation. Degraded and/or aggregated protein as well as the presence of any of the conventional excipients can result in immunogenic or anaphylactic reactions, and reduced bioavailability of the protein drug. The aim of this work was to select novel RNA-based stabilizers of bovine insulin which would recognize and bind to the monomeric protein and help retain its bioactivity. RNA aptamers were selected by an in vitro selection method. They were screened for their ability to inhibit insulin fibrillation using agitation as a stress condition. The in vitro activity of insulin was determined by phosphorylation of downstream proteins in the cell. In vivo bioactivity was determined in a diabetic rat model. RNA aptamers, which bound to insulin with very low dissociation constants and high specificity, were selected. These sequences were aligned and consensus regions were found. The RNA sequences had no effect on the signalling cascade initiated by insulin. The bioactivity of insulin, as measured by its ability to lower plasma glucose level in a diabetic rat model, also remained unchanged. RNA aptamers are a novel class of protein stabilizers which have the ability to disrupt protein-protein interactions and hence inhibit protein aggregation. Their non-toxic and non-immunogenic nature makes such formulations safe for use.

Comparison of arterial and mixed venous blood glucose levels in hemodynamically unstable pigs: implications for location of a continuous glucose sensor

One of several unsolved challenges in the construction of an artificial endocrine pancreas (a system for automatically adjusting the blood glucose level) is the positioning of the glucose sensor. We believe the best positioning to be either intraarterial or in a central vein. It is therefore important to know whether the glucose content in these blood locations is the same. We conducted a post hoc analysis of previously collected data from pigs exposed to gross inflammatory and circulatory stress. Paired arterial and mixed venous glucose values were compared with a mixed effects model. We found the blood glucose values from the arterial and mixed venous blood to be the same.

A discovery-phase urine proteomics investigation in type 1 diabetes

Diabetes is a chronic metabolic disease which can lead to serious health problems particularly in and to the development of cardiovascular and renal complications. The aim of this study is to possibly identify distinctive molecular features in urine samples which might correlate to the progression and complications of type 1 diabetes. Diabetic patients with normo- and micro-albuminuria have been analyzed and compared to a group of control subjects. Urine proteins of control and type 1 diabetes subjects were investigated in their proteome profiles, using high-resolution two-dimensional gel electrophoresis separation and protein identifications by MALDI-TOF-MS and LC-MS/MS analysis. Proteomics analysis highlighted differential expression of several proteins between control and type 1 diabetes subjects. In particular, five proteins were found to be down-regulated and four proteins up-regulated. Lower protein representations in diabetic subjects were associated with Tamm-Horsfall urinary glycoprotein, apolipoprotein A-I, apolipoprotein E, α2-thiol proteinase inhibitor, and human complement regulatory protein CD59, while higher protein representations were found for α-1-microglobulin, zinc-α2 glycoprotein, α-1B glycoprotein, and retinol-binding protein 4. These differences were maintained comparing control subjects with type 1 diabetes normo-albuminuric and micro-albuminuric subjects. Furthermore, these proteins are correlated to glycosylated hemoglobin and microalbuminuria, confirming their role in diabetic pathology. This study gives new insights on potential molecular mechanisms associated with the complications of type 1 diabetic disease providing evidences of urine proteins potentially exploitable as putative prognostic biomarkers.

Experiment on the feasibility of using modified gelatin nanoparticles as insulin pulmonary administration system for diabetes therapy

Polymeric nanoparticles are widely used as targeted carriers for biomacromolecules. In this paper, modified gelatin nanoparticles were prepared and their feasibility as insulin pulmonary administration system was investigated. D: ,L: -glyceraldehyde and poloxamer 188 were used for gelatin nanoparticle preparation. Novel water-in-water emulsion technique was used to prepare insulin-loaded nanoparticles. Morphological examination of insulin-loaded nanoparticles was carried out using scanning electron microscopy (SEM). Intratracheal instillation of insulin-loaded nanoparticles was performed to evaluate animal hypoglycemic effect. With fluorescence labeling of insulin, alveolar deposition and absorption of insulin-loaded nanoparticles were investigated. Histological changes in the lung were also observed to evaluate the safety. From the micromorphology observation, insulin-loaded nanoparticles under gelatin-poloxamer 188 ratio at 1:1 showed smooth and uniform surface, with average particle size 250 nm and Zeta potential -21.1 mV. From animal experiment, insulin-loaded nanoparticles under gelatin-poloxamer 188 ratio at 1:1 promoted insulin pulmonary absorption effectively and showed good relative pharmacological bioavailability. Proved by alveolar deposition result, FITC-insulin-loaded nanoparticle group was characterized by an acute and rapid hypoglycemic effect. In addition, nanoparticles could guarantee the safety of lung by reducing insulin deposition in lung. A transient weak inflammatory response was observed at 1 day after administration. With good physical characterization, high bioavailability, fast and stable hypoglycemic effect, insulin-loaded nanoparticles might be developed as a novel insulin pulmonary system for diabetes therapy.