Clustering of immunological, metabolic and genetic features in latent autoimmune diabetes in adults: evidence from principal component analysis

Do diabetes phenotypes in US women differ by race/ethnicity? A population-based cluster analysis

Objective

US women exhibit racial disparities in the lifetime risk of diabetes and related outcomes. Identifying heterogeneity in clinical presentation may assist with reducing racial disparities in diabetes outcomes. We identified clinical phenotypes of diabetes and examined their racial and ethnic distribution in US women.

Research design and methods

We conducted cluster analysis based on five factors in US women with diagnosed diabetes assessed in the National Health and Nutrition Examination Surveys 1999-2018 (n = 825). Multinomial logistic regression analysis was performed to identify racial and ethnic differences in the distribution of phenotypes.

Results

We identified four distinct clinical phenotypes. Two phenotypes, mild age-related and severe insulin-deficient diabetes, each included approximately a third of women. Mild insulin-resistant and severe insulin-resistant diabetes phenotypes accounted for 19.9% and 13.7%, respectively. The distribution of clusters did not differ by race and ethnicity.

Conclusions

The prevalence of four clinically distinct diabetes phenotypes identified in US women did not differ by race and ethnicity.

The Identification of Diabetes Mellitus Subtypes Applying Cluster Analysis Techniques: A Systematic Review

Diabetes Mellitus is a chronic and lifelong disease that incurs a huge burden to healthcare systems. Its prevalence is on the rise worldwide. Diabetes is more complex than the classification of Type 1 and 2 may suggest. The purpose of this systematic review was to identify the research studies that tried to find new sub-groups of diabetes patients by using unsupervised learning methods. The search was conducted on Pubmed and Medline databases by two independent researchers. All time publications on cluster analysis of diabetes patients were selected and analysed. Among fourteen studies that were included in the final review, five studies found five identical clusters: Severe Autoimmune Diabetes; Severe Insulin-Deficient Diabetes; Severe Insulin-Resistant Diabetes; Mild Obesity-Related Diabetes; and Mild Age-Related Diabetes. In addition, two studies found the same clusters, except Severe Autoimmune Diabetes cluster. Results of other studies differed from one to another and were less consistent. Cluster analysis enabled finding non-classic heterogeneity in diabetes, but there is still a necessity to explore and validate the capabilities of cluster analysis in more diverse and wider populations.

[Features of the development of latent autoimmune diabetes in adults (LADA)]

The study of the sociomedical problems of diabetes mellitus led to the discovery of latent autoimmune diabetes in adults (LADA), a special form of the disease. The slow onset of the disease, the clinical signs of type 2 diabetes mellitus concurrent with the autoantibody pancreatic β-cell destruction mechanism that is characteristic of type 1 diabetes. Genetic factors play an important role in the genesis of the disease. Insulitis concurrent with intact or hypertrophic islets of the gland originally develops morphologically. Subsequently, the phenomena of islet atrophy and sclerosis are progressive. The disease is typical for young people (generally those aged 25-35 years) with normal body mass index, low blood C-peptide levels, with antibodies against β-cells, primarily to glutamate decarboxylase, being detected. Insulin preparations should be used to treat these patients.

Association of common type 1 and type 2 diabetes gene variants with latent autoimmune diabetes in adults: A meta-analysis

BACKGROUND

The aim of this meta-analysis was to determine the association of common type 1 diabetes (T1D) and type 2 diabetes (T2D) gene variants (protein tyrosine phosphatase non-receptor 22 [PTPN22] rs2476601C/T, insulin [INS] rs689A/T and transcription factor 7-like 2 [TCF7L2] rs7903146C/T) with latent autoimmune diabetes in adults (LADA).

METHODS

A systematic search of electronic databases was conducted up to 2017 and data from 16 independent case-control studies for three gene variants were pooled. The pooled allele and genotype frequencies for each T1D and T2D gene variant were used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Heterogeneity tests and evaluation of publication bias were performed for all studies.

RESULTS

In all, 8869 cases and 20 829 controls pooled from 16 case-control studies were included in the analysis. For rs2476601, a significant association was found for homozygote TT (OR 2.67; 95% CI 1.92-3.70; P < 0.0001), heterozygote CT (OR 1.61; 95% CI 1.44-1.79; P < 0.0001), and the T allele (OR 1.62; 95% CI 1.48-1.78; P < 0.0001). Overall, a significant inverse association was observed for rs689 in the TT genotype (OR 0.43; 95% CI 0.30-0.64; P < 0.0001), AT genotype (OR 0.53; 95% CI 0.45-0.62; P < 0.0001), and T allele (OR 0.61; 95% CI 0.52-0.71; P < 0.0001). For the rs7903146 polymorphism, the T allele (OR 1.19; 95% CI 1.00-1.40; P = 0.04) may be associated with the risk of LADA.

CONCLUSION

The rs2476601C/T, rs689A/T, and rs7903146C/T polymorphisms were found to be associated with the risk of LADA, thereby indicating that, genetically, LADA could be an admixture of both T1D and T2D.

Leptin Levels and Insulin Dependence in Latent Autoimmune Diabetes in Adults

Latent autoimmune diabetes in adults (LADA) is an autoimmune type of diabetes accounting for up to 10% of all cases of diabetes initially diagnosed as type 2 diabetes mellitus. It has been demonstrated that LADA patients with a lower body mass index (BMI) undergo a faster depletion of beta cell function and require insulin therapy earlier. In this study, we assayed a panel of adipokines (leptin, adiponectin, omentin, resistin, visfatin) and proinflammatory cytokines (interleukin 2, interleukin 6, tumor necrosis factor-α) in 71 LADA patients and tested the association with a number of clinical and immunological features. Among men, leptin was positively and significantly correlated with BMI and fat mass (r = 0.487 and r = 0.664, respectively), resistin was positively and significantly correlated with total and low-density lipoprotein cholesterol (r = 0.644 and r = 0.746, P < 0.0001) and with interleukin 2 (r = 0.688, P < 0.01). Omentin showed an inverse correlation with systolic blood pressure in women (r = -0.359, P < 0.001) and a positive correlation with interleukin 2 in both genders (r = 0.395, P < 0.01). The Cox regression analysis showed that leptin levels were inversely and significantly related with the risk of early insulin dependence. Higher leptin secretion may exert a direct effect on beta cell function leading to more insulin sensitivity.

Increased seroreactivity to proinsulin and homologous mycobacterial peptides in latent autoimmune diabetes in adults

Latent Autoimmune Diabetes in Adults (LADA) is a slowly progressing form of immune-mediated diabetes that combines phenotypical features of type 2 diabetes (T2D) with the presence of islet cell antigens detected in type 1 diabetes (T1D). Heterogeneous clinical picture have led to the classification of patients based on the levels of antibodies against glutamic acid decarboxylase 65 (GADA) that correlate with clinical phenotypes closer to T1D or T2D when GADA titers are high or low, respectively. To date, LADA etiology remains elusive despite numerous studies investigating on genetic predisposition and environmental risk factors. To our knowledge, this is the first study aimed at evaluation of a putative role played by Mycobacterium avium subsp. paratuberculosis (MAP) as an infective agent in LADA pathogenesis. MAP is known to cause chronic enteritis in ruminants and has been associated with autoimmune disorders in humans. We analyzed seroreactivity of 223 Sardinian LADA subjects and 182 healthy volunteers against MAP-derived peptides and their human homologs of proinsulin and zinc transporter 8 protein. A significantly elevated positivity for MAP/proinsulin was detected among patients, with the highest prevalence in the 32-41-year-old T1D-like LADA subgroup, supporting our hypothesis of a possible MAP contribution in the development of autoimmunity.

Organ-specific antibodies in LADA patients for the prediction of insulin dependence

AIM OF THE STUDY

The aim of the present study was to define the frequency of organ-specific and non-organ-specific autoantibodies in a cohort of Latent Autoimmune Diabetes in Adults (LADA) patients and to test whether multiple antibodies positivity could be a predictor of early insulin dependence.

MATERIALS AND METHODS

We enrolled 210 LADA and 210 type 2 diabetes mellitus (T2D) patients. In all subjects anti-islet antigen-2 (IA-2Ab), anti-thyroperoxidase (TPOAb), anti-zinc transporter 8 (ZnT8Ab), anti-nuclear (ANA), anti-parietal cell (APCA), anti-smooth muscle (ASMA), anti-mitochondrial (AMA), anti-liver kidney microsomes (LKM), and anti-reticulin (ARA) circulating antibodies were assessed.

RESULTS

The frequency of TPOAb, ZnT8Ab, APCA, and IA-2Ab positivity was, respectively, detected in 40.0%, 32.4%, 24.7%, and 9.5% of LADA patients, whereas their frequency was significantly lower in T2D patients (11.4%, 1.9%, 9.5%, and 0.0%, respectively, p < 0.001). The frequency of ANA was the same in both groups whereas the frequency of ASMA, ARA, AMA, and LKM was very low (range 0.0-3.3%). The presence of TPOAb associated with ZnT8Ab, IA-2Ab, or APCA allows one to predict the progression of disease with a high specificity but low sensibility.

CONCLUSIONS

LADA patients show an increased frequency of organ- and non-organ-specific antibodies. Consequently, a screening is worthwhile in these patients. The simultaneous presence of TPOAb with ZnT8, IA-2Ab, or APCA may help differentiate clinical phenotypes and predict faster insulin dependence in LADA patients.

Implication of Cytotoxic Helicobacter pylori Infection in Autoimmune Diabetes

Background. Type 1 diabetes (T1D) and type 2 diabetes (T2D) have been linked to Helicobacter pylori infection, although results are conflicting. No previous study addressed a possible link between H. pylori infection and latent autoimmune diabetes in adults (LADA). In this study, a correlation among H. pylori infection and the risk of autoimmune diabetes in comparison with T2D was investigated. Methods. Sera from 234 LADA patients, 105 patients with late-onset T1D, and 156 patients with T2D were analyzed for anti-H. pylori and the cytotoxin-associated antigen (CagA) IgG antibodies. Results. H. pylori seroprevalence was comparable in LADA (52%), late-onset T1D (45%), and T2D (49%) with no gender differences. The seroprevalence of CagA IgG was significantly higher in autoimmune diabetes (late-onset T1D: 45%, LADA: 40%) compared to T2D (25%; p < 0.028). Conclusions. Although H. pylori seroprevalence was similar in LADA, T1D, and T2D, anti-CagA positivity was significantly increased among patients with autoimmune diabetes, suggesting that more virulent H. pylori strains might be a trigger for immune mechanisms involved in their pathogenesis.