Progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody

Development and validation of a clinical score for identifying patients with high risk of latent autoimmune adult diabetes (LADA): The LADA primary care-protocol study

BACKGROUND

Latent autoimmune diabetes in adults (LADA) is a type of diabetes mellitus showing overlapping characteristics between type 1 Diabetes Mellitus and type 2 Diabetes Mellitus (T2DM), and autoimmunity against insulin-producing pancreatic cells. For its diagnosis, at least one type of anti-pancreatic islet antibody (GADAb is the most common) is required. Many authors recommend performing this measure in all newly diagnosed patients with DM, but it is not possible in Primary Health Care (PHC) due to its high cost. Currently, a relevant proportion of patients diagnosed as T2DM could be LADA. Confusing LADA with T2DM has clinical and safety implications, given its different therapeutic approach. The main objective of the study is to develop and validate a clinical score for identifying adult patients with DM at high risk of LADA in PHC.

METHODS

This is an observational, descriptive, cross-sectional study carried out in Primary Care Health Centers with a centralized laboratory. All people over 30 years of age diagnosed with diabetes within a minimum of 6 months and a maximum of 4 years before the start of the study will be recruited. Individuals will be recruited by consecutive sampling. The study variables will be obtained through clinical interviews, physical examinations, and electronic medical records. The following variables will be recorded: those related to Diabetes Mellitus, sociodemographic, anthropometric, lifestyle habits, laboratory parameters, presence of comorbidities, additional treatments, personal or family autoimmune disorders, self-perceived health status, Fourlanos criteria, and LADA diagnosis (as main variable) according to current criteria.

DISCUSSION

The study will provide an effective method for identifying patients at increased risk of LADA and, therefore, candidates for antibody testing. However, a slight participation bias is to be expected. Differences between participants and non-participants will be studied to quantify this potential bias.

Age at Diagnosis and the Risk of Diabetic Nephropathy in Young Patients with Type 1 Diabetes Mellitus

BACKGROUND

The aim of this study was to evaluate characteristics and risk of diabetic complications according to age at diagnosis among young adults with type 1 diabetes mellitus (T1DM).

METHODS

A total of 255 T1DM patients aged less than 40 years were included. Patients were categorized into three groups (<20, 20 to 29, and 30 to 40 years) according to age at diagnosis. Diabetic nephropathy (DN) was defined when spot urine-albumin creatinine ratio was 300 mg/g or more and/or estimated glomerular filtration ratio (eGFR) level was 60 mL/min/1.73 m2 or less.

RESULTS

Median age at diagnosis was 25 years and disease duration was 14 years. Individuals diagnosed with T1DM at childhood/adolescent (age <20 years) had lower stimulated C-peptide levels. They received more intensive insulin treatment with higher total daily insulin doses compared to older onset groups. The prevalence of DN was higher in the childhood/adolescent-onset group than in older onset groups (25.3% vs. 15.3% vs. 9.6%, P=0.022). The eGFR was inversely associated with disease duration whilst the degree of decrease was more prominent in the childhood/adolescent-onset group than in the later onset group (aged 30 to 40 years; P<0.001). Childhood/adolescent-onset group was independently associated with the risk of DN compared to the older onset group (aged 30 to 40 years; odds ratio, 3.47; 95% confidence interval, 1.45 to 8.33; P=0.005).

CONCLUSION

In individuals with childhood/adolescent-onset T1DM, the reduction in renal function is more prominent with disease duration. Early age-onset T1DM is an independent risk of DN.

The impact of phenotype, ethnicity and genotype on progression of type 2 diabetes mellitus

AIM

To conduct a comprehensive review of studies of glycaemic deterioration in type 2 diabetes and identify the major factors influencing progression.

METHODS

We conducted a systematic literature search with terms linked to type 2 diabetes progression. All the included studies were summarized based upon the factors associated with diabetes progression and how the diabetes progression was defined.

RESULTS

Our search yielded 2785 articles; based on title, abstract and full-text review, we included 61 studies in the review. We identified seven criteria for diabetes progression: 'Initiation of insulin', 'Initiation of oral antidiabetic drug', 'treatment intensification', 'antidiabetic therapy failure', 'glycaemic deterioration', 'decline in beta-cell function' and 'change in insulin dose'. The determinants of diabetes progression were grouped into phenotypic, ethnicity and genotypic factors. Younger age, poorer glycaemia and higher body mass index at diabetes diagnosis were the main phenotypic factors associated with rapid progression. The effect of genotypic factors on progression was assessed using polygenic risk scores (PRS); a PRS constructed from the genetic variants linked to insulin resistance was associated with rapid glycaemic deterioration. The evidence of impact of ethnicity on progression was inconclusive due to the small number of multi-ethnic studies.

CONCLUSION

We have identified the major determinants of diabetes progression-younger age, higher BMI, higher HbA1c and genetic insulin resistance. The impact of ethnicity is uncertain; there is a clear need for more large-scale studies of diabetes progression in different ethnic groups.

Anti-glutamic acid decarboxylase antibody positive neurological syndromes

A rare kind of antibody, known as anti-glutamic acid decarboxylase (GAD) autoantibody, is found in some patients. The antibody works against the GAD enzyme, which is essential in the formation of gamma aminobutyric acid (GABA), an inhibitory neurotransmitter found in the brain. Patients found with this antibody present with motor and cognitive problems due to low levels or lack of GABA, because in the absence or low levels of GABA patients exhibit motor and cognitive symptoms. The anti-GAD antibody is found in some neurological syndromes, including stiff-person syndrome, paraneoplastic stiff-person syndrome, Miller Fisher syndrome (MFS), limbic encephalopathy, cerebellar ataxia, eye movement disorders, and epilepsy. Previously, excluding MFS, these conditions were calledhyperexcitability disorders. However, collectively, these syndromes should be known as "anti-GAD positive neurological syndromes." An important limitation of this study is that the literature is lacking on the subject, and why patients with the above mentioned neurological problems present with different symptoms has not been studied in detail. Therefore, it is recommended that more research is conducted on this subject to obtain a better and deeper understanding of these anti-GAD antibody induced neurological syndromes.

Urinary Glucose Screening for Early Detection of Asymptomatic Type 2 Diabetes in Jeonbuk Province Korean Schoolchildren

This study aimed to investigate the prevalence of glucosuria and the characteristics of diabetes in schoolchildren as detected by a school urine glucose screening program implemented from 2010 to 2013 in the Jeonbuk province area of Korea. A total of 110 children without known diabetes were analyzed. They were checked with an oral glucose tolerance test (OGTT) with other laboratory tests and their clinical data were collected. A total of 707,238 schoolchildren from a school population of 1,064,999 were screened for glucosuria. In total, over a 4-year period, 545 schoolchildren (0.077%) were positive for glucosuria on the second urine test. The prevalence of glucosuria was more common among middle and high schoolchildren than among elementary schoolchildren. Among 110 students who completed the OGTT to confirm diabetes, 40 were diagnosed with diabetes mellitus (DM); 39 children, type 2 diabetes mellitus (T2DM) and 1 child, slowly progressive insulin dependent diabetes mellitus (SPIDDM). The mean annual incidence of diabetes was 5.6 per 100,000 schoolchildren and adolescents. The subjects with diabetes diagnosed through the urine screening test showed minimal or no symptoms of diabetes. The students with diabetes were more likely to be woman and obese, and they have a higher body mass index, higher cholesterol, triglyceride, insulin, C-peptide, and fasting glucosuria values than the students with normal glucose tolerance. We identified 40 new cases of diabetes in the Korean schoolchildren with asymptomatic glucosuria on urine glucose screening. This finding shows that school urine glucose screening is a feasible and simple method for early detection of asymptomatic T2DM.

Protein Modifications as Manifestations of Hyperglycemic Glucotoxicity in Diabetes and Its Complications

Diabetes and its complications are hyperglycemic toxicity diseases. Many metabolic pathways in this array of diseases become aberrant, which is accompanied with a variety of posttranslational protein modifications that in turn reflect diabetic glucotoxicity. In this review, we summarize some of the most widely studied protein modifications in diabetes and its complications. These modifications include glycation, carbonylation, nitration, cysteine S-nitrosylation, acetylation, sumoylation, ADP-ribosylation, O-GlcNAcylation, and succination. All these posttranslational modifications can be significantly attributed to oxidative stress and/or carbon stress induced by diabetic redox imbalance that is driven by activation of pathways, such as the polyol pathway and the ADP-ribosylation pathway. Exploring the nature of these modifications should facilitate our understanding of the pathological mechanisms of diabetes and its associated complications.

Hyperglycemic Stress and Carbon Stress in Diabetic Glucotoxicity

Diabetes and its complications are caused by chronic glucotoxicity driven by persistent hyperglycemia. In this article, we review the mechanisms of diabetic glucotoxicity by focusing mainly on hyperglycemic stress and carbon stress. Mechanisms of hyperglycemic stress include reductive stress or pseudohypoxic stress caused by redox imbalance between NADH and NAD(+) driven by activation of both the polyol pathway and poly ADP ribose polymerase; the hexosamine pathway; the advanced glycation end products pathway; the protein kinase C activation pathway; and the enediol formation pathway. Mechanisms of carbon stress include excess production of acetyl-CoA that can over-acetylate a proteome and excess production of fumarate that can over-succinate a proteome; both of which can increase glucotoxicity in diabetes. For hyperglycemia stress, we also discuss the possible role of mitochondrial complex I in diabetes as this complex, in charge of NAD(+) regeneration, can make more reactive oxygen species (ROS) in the presence of excess NADH. For carbon stress, we also discuss the role of sirtuins in diabetes as they are deacetylases that can reverse protein acetylation thereby attenuating diabetic glucotoxicity and improving glucose metabolism. It is our belief that targeting some of the stress pathways discussed in this article may provide new therapeutic strategies for treatment of diabetes and its complications.

Insulin secretion in patients with latent autoimmune diabetes (LADA): half way between type 1 and type 2 diabetes: action LADA 9

BACKGROUND

The study of endogenous insulin secretion may provide relevant insight into the comparison of the natural history of adult onset latent autoimmune diabetes (LADA) with types 1 and 2 diabetes mellitus. The aim of this study was to compare the results of the C-peptide response to mixed-meal stimulation in LADA patients with different disease durations and subjects with type 2 and adult-onset type 1 diabetes.

METHODS

Stimulated C-peptide secretion was assessed using the mixed-meal tolerance test in patients with LADA (n = 32), type 1 diabetes mellitus (n = 33) and type 2 diabetes mellitus (n = 30). All patients were 30 to 70 years old at disease onset. The duration of diabetes in all groups ranged from 6 months to 10 years. The recruitment strategy was predefined to include at least 10 subjects in the following 3 disease onset categories for each group: 6 to 18 months, 19 months to 5 years and 5 to 10 years.

RESULTS

At all time-points of the mixed-meal tolerance test, patients with LADA had a lower stimulated C-peptide response than the type 2 diabetes group and a higher response than the type 1 diabetes group. The same results were found when the peak or area under the C-peptide curve was measured. When the results were stratified by time since disease onset, a similar pattern of residual insulin secretory capacity was observed.

CONCLUSIONS

The present study shows that the magnitude of stimulated insulin secretion in LADA is intermediate between that of type 1 and type 2 diabetes mellitus.