دیابت شیرین، شیوع، پاتولوژی، انواع و عوارض.

Introduction: The prevalence of diabetes mellitus (DM) in worldwide is growing rapidly which may be mostly due to considerable changes in the lifestyle of modern humans. Dynamic modeling has suggested that total diagnosed and undiagnosed cases of DM are predicted to rise from 14% in 2010 to about 33% by 2050 among the US adult population. This issue imposes huge amounts of costs on individuals and health-providing systems annually. DM is the most prevalent metabolic disorder in humans that extensively affects on metabolism of main substrates i.e. carbohydrates and lipids and deviated normal metabolic pathways toward the un-usual process leading to the generation of injurious metabolites e.g. free radicals. DM is categorized into three main classes as type 1; type 2 and gestational diabetes. Type 1 DM (T1DM) or Insulin-dependent diabetes mellitus (IDDM) is mainly referred to as lower circulatory insulin. Type 2 DM (T2DM) or non-insulin-dependent diabetes mellitus (NIDDM) is the most prevalent form of DM and is mainly associated with insulin resistance in peripheral tissues. Gestational diabetes is another common type of DM that occurs in pregnant women probably due to hormonal variations. Furthermore, we know other forms of DM with lower prevalence such as LADA (Latent Autoimmune Diabetes in Adults), Maturity)Onset Diabetes of the Young (MODY), and secondary diabetes to different conditions such as pancreatitis and secondary diabetes to some drugs e.g. corticosteroids. It has been confirmed that DM is a potent upstream event for many vascular complications known as diabetic complications. It can onset and progress a wide series of devastating molecular mechanisms and pathogenic signaling pathways involved in tissue dysfunction, disabilities as well as in many matters of mortalities. Although numerous studies have surveyed the pathophysiology of DM, however, the exact underlying cause of it is unclear yet. However, the role of some pharmacological agents is prominent. Moreover, in cases of uncontrolled diabetes, various diabetic complications develop in different organs/tissues which may result in total failure of organs' function. Besides many in vitro and in vivo studies about underlying molecular mechanisms of DM, its exact pathophysiology is still unclear. However, some strong hypotheses such as insulin resistance, beta cells' dysfunction/apoptosis and lower circulatory insulin, oxidative stress, mitochondrial dysfunction, and inflammation have been suggested. Insulin resistance (IR) is a complex pathological state of inappropriate cellular response to insulin hormone in insulin‐dependent cells such as adipocytes and cardiomyocytes. IR is present in many metabolic disorders, such as type 2 DM and metabolic syndrome, and is responsible for many metabolic perturbations. IR is inversely correlated to insulin sensitivity in insulin‐dependent tissues and disables their ability to take up and utilize glucose, the preferred metabolic substrate. The decline in insulin sensitivity exposes the tissue to metabolic deviations and IR. Although the precise pathophysiology of IR is not clear, certain molecular mechanisms are known to be involved. [ABSTRACT FROM AUTHOR]