ACTA ENDOCRINOLOGICA (BUC)

Diabetes mellitus is a complex disorder of the energy metabolism of the human body. In the last WHO/ADA classification, the main forms of this disease are Type 1 (T1DM) and Type 2 (T2DM) diabetes mellitus. According to the same classification, the pathogenesis of T2DM is considered to include a progressive insulin secretory defect on the background of insulin resistance. Recently, controversies surround the concept of peripheral insulin\r\nresistance emerging in the 70's as an attempt to explain the differences from the T1DM phenotype whose autoimmune nature was as that time revealed. The insulin resistance\r\nhypothesis was based on the supposition that high plasma insulin levels are the result of a primary molecular defect against which the normal beta cells will react with an increased insulin secretion. This hypothesis has been\r\nused to explain both the pathogenesis of T2DM and the metabolic syndrome, named also for a short period of time "the insulin resistance syndrome". We will try to argue\r\nthat what it is attributed to peripheral insulin\r\nresistance belongs in fact to obesity. Special emphasis is put on the role of the adipocytes, including the secretion of different adipokines with the secondary lipotoxicity, oxidative stress and pro-inflammatory reaction, explaining the complex relationship between obesity and diabetes.

Aims. To investigate the historical changes in survival with diabetes in patients treated with insulin from diagnosis.\r\nMethods. We analyzed 2811 deaths, 51.5% males, registered at ?I. Pavel? Bucharest Diabetes Centre, aged 40-64 years and deceased between 1943 and 2009. We split the analysis in three time periods according to year of death: 1943-1965,\r\n1966-1988 and 1989-2009.\r\nResults. The mean age at diabetes onset was 51.4?6.8 years, with mean disease duration at death of 17.7?11.6 years\r\nand mean age at death of 69.1?11.2 years. The mean survival after diabetes onset was 13.9?9.8 years in 1943-1965, and rose to 17.3?9.6 years (p<0.001) in 1989-2009. There was a significant increase for coronary heart diseases and cancer and a significant decrease for infections and endstage\r\nrenal disease as causes of death.\r\nConclusions. We found no significant changes in age at onset, which combined with an increase in survival with diabetes lead to a significant increase in age at death.\r\nMajor historical events have a strong impact over survival after the onset of diabetes.

Based on epidemiological, clinic, biochemical and hormonal data (both personal and\r\ninternational), our personal view is that natural history of autoimmune type 1 diabetes could\r\ninclude the following stages: 1) The presence of a complex genetic predisposition towards ?\r\ncell autoimmunity (possibly &#8220;latent&#8221; until death); 2) The &#8220;initiation&#8221; of autoimmunity in\r\nsubjects carrying a defect in the post-translational processing of pre-proinsulin/ proinsulin/\r\ninsulin, manifested precociously as increased proinsulin-to-insulin ratio; 3) Stimulation by the\r\nincreased proinsulin of the plasmacytoid dendritic cell clones capable to capture the natural\r\nantigens (proinsulin/insulin, Glutamic Acid Decarboxylase, etc.) from the pancreatic beta\r\ncells; 4) Activation of the process generating reactive T cell clones (Teffs) in the detriment of\r\nprotective immuno-regulatory T cell clones (Tregs), triggering the anti-beta cell attack,\r\nexpressed as autoimmune insulitis and/or the presence of circulating anti beta cell antibodies;\r\n5) The onset of the beta cell apoptosis process mediated by pro-inflammatory cytokines (IFN\r\n?, TNF ?, IL6) or by the direct contact between Teffs and the beta cells; 6) Identification of\r\nthe first secretory beta cell defects (the loss of the first phase insulin response followed by the\r\nprogressive decrease of the area under the insulin curve and the progressive increase of the\r\narea under the blood glucose curve) while fasting glycemia is still normal; 7) The progressive\r\nloss of the beta cell mass. All these processes take place during the pre-hyperglycemic stage\r\nof diabetes, with a higher or lower speed depending on the genetic background. The overt\r\nclinical stage of diabetes, marked by the presence of hyperglycemia, occurs rather late, when\r\nmore than 90% of the beta cell function/mass is irreversibly lost.

Diabetes Mellitus is a huge syndrome which can be detected from the first day of life until the last year of life of a centenarian. In the current classification of diabetes among the so-called “idiopathic phenotypes”, apart Type 1 Diabetes (T1D) and Type 2 Diabetes (T2D) has been included provisionally term “Latent Autoimmune Diabetes in Adults” (LADA). This has unclear characterization regarding the age at onset, the presence of anti-β-cell antibodies and the level of insulin secretory function, in conformity with C-peptide levels. According to several recent publications, there are no specific biochemical or genetic markers for Latent Autoimmune Diabetes in Adults (LADA), but only a gradual transition from T1D to T2D. In addition, the word “latent” in the construction of “LADA” term is inaccurate because in this phenotype nothing is latent: both the autoimmunity and diabetes are present and are even parts of the diagnosis. So that, the best term should be what in reality this subphenotype is: an Intermediary Diabetes Mellitus (IDM). Some recent genetic data strongly support this designation.