Conclusion Understanding the complexity of the molecular and biochemical basis of insulin impairment, along with microvascular disease in diabetes mellitus, is achieved with a method that uses the conceptualization in which they are taken into account Considering the interactions, in the case of insulin dysfunction and resistance, the interconnections and correlations between glucose, insulin signaling, with associated molecules and substrates regulating various tissues of metabolic importance are key approaches to understanding such pathways. With the various molecules involved, participating in both normal and dysfunctional pathways and mechanisms, intracellular signal processing was provided by the inducer, in that of insulin where it bound to the insulin receptor substrate, IRS. Other molecules, consisting of PK13, PKB, and PKC along with their derivatives and isotopes, were also of great importance due to the strong evidence supporting that dysfunction of these proteins in their homeostatic form contributed to the overall process of insulin resistance. As regards retinopathy, the main cause of blindness in patients suffering from diabetes mellitus, the molecular basis and the accreditation of the resulting pathology is mainly due to the polyol pathway, in which glucose is reduced to sorbitol, consequently being converted into fructose. This mechanism is activated when glucose levels increase abnormally where the level of cellular toxicity occurs in diabetic hyperglycemia where the products of this pathway and the associated cofactors and substrates that contribute, such as aldose reductase in the rate-limiting step of the enzymatic pathway , demonstrate that the abnormalities that occur due to retinopathy are... half of the paper... highly polymorphic to the immune system, which include such molecules including HLA which is classified as a class 1 dimeric molecular protein, with the function expected to present antigenic peptides to CD8 T cells. (Mark A. Atkinson, Noel K. Maclaren, 1994) Second, HLA class II is also known to be dimeric, while their characteristic perception demonstrates constitutive expression or enhanced induction on the surface of antigen-presenting cells. The interaction that occurs between a cell that possesses an HLA molecule in contact with an antigenic peptide and a T lymphocyte, with a receptor present, would demonstrate a process in which the recognition of HLA and the peptide that forms a complex would involve the instigation of T lymphocyte activation and proliferation where this immune response underlies almost all immune responses. (Mark A.