pyrimidinones and Diabetes-Mellitus--Type-1

Topics: Adolescent; Age Factors; Albuterol; Androstadienes; Anticonvulsants; Asthma; Atovaquone; Attention Deficit Disorder with Hyperactivity; Beclomethasone; Carbamazepine; Child; Delayed-Action Preparations; Diabetes Mellitus, Type 1; Drug Approval; Drug Combinations; Drug Delivery Systems; Drug Therapy; Epilepsies, Partial; Fluticasone-Salmeterol Drug Combination; HIV Protease Inhibitors; Humans; Insulin; Insulin Glargine; Insulin, Long-Acting; Lopinavir; Methylphenidate; Naphthoquinones; Nebulizers and Vaporizers; Oxcarbazepine; Pediatrics; Proguanil; Pyrimidinones; Ritonavir; United States

Preserving endogenous insulin production is clinically advantageous and remains a vital unmet challenge in the treatment and reversal of type 1 diabetes. Although broad immunosuppression has had limited success in prolonging the so-called remission period, it comes at the cost of compromising beneficial immunity. Here, we used a novel strategy to specifically deplete the activated diabetogenic T cells that drive pathogenesis while preserving not only endogenous insulin production but also protective immunity. Effector T (Teff) cells, such as diabetogenic T cells, are naturally poised on the edge of apoptosis because of activation-induced DNA damage that stresses the p53 regulation of the cell cycle. We have found that using small molecular inhibitors that further potentiate p53 while inhibiting the G2/M cell cycle checkpoint control drives apoptosis of activated T cells in vivo. When delivered at the onset of disease, these inhibitors significantly reduce diabetogenic Teff cells, prolong remission, preserve functional islets, and protect islet allografts while leaving naive, memory, and regulatory T-cell populations functionally untouched. Thus, the targeted manipulation of p53 and cell cycle checkpoints represents a new therapeutic modality for the preservation of islet β-cells in new-onset type 1 diabetes or after islet transplant.

Topics: Animals; Diabetes Mellitus, Type 1; Enzyme Inhibitors; Imidazoles; Mice; Mice, Inbred NOD; Pancreas; Piperazines; Pyrazoles; Pyrimidines; Pyrimidinones; T-Lymphocytes; Thiophenes; Urea

The changes of asymmetric distribution of anionic phospholipids of human platelets in diabetic patients were studied by fluorescent and freeze fracture cytochemistry, using merocyanine 540 (MC 540) and polymyxin B (PxB) as specific markers. The membrane anionic phospholipids were detected with PxB, a membrane nonpermeant probe, used either in native form for freeze fracture electron microscopy or as dansylated or iodinated derivative for fluorescence microscopy or gamma counting, respectively. MC 540 is a naturally fluorescent probe which reportedly inserts into less packed bilayer domains. Both in platelet rich plasma and in washed platelets obtained from diabetic patients, some small platelet aggregates were observed, their number being generally dependent on the level of hyperglycemia. In contrast with single platelets, the aggregated ones bind PxB as revealed by all assay methods. The fluorescence microscopic studies with dansyl PxB and MC 540 displayed a strong binding of the fluorescent markers to aggregated platelets. The electron microscopic examination of freeze fracture replicas showed the appearance of characteristic PxB-induced deformations in the plasmalemma of aggregated platelets. The gamma counting of 125I-PxB incubated samples indicates significant differences on the platelets of diabetic patients as compared to those obtained from healthy subjects. Our data provide evidence that in diabetic patients, the spontaneous aggregated platelets are a result of the appearance of the anionic phospholipids in the outer half of plasmalemma. These changes may enhance the procoagulant activity and should represent a determinant of activated platelet recognition and their removal from circulation by splenic macrophages.

Topics: Anions; Blood Platelets; Cell Membrane; Diabetes Mellitus, Type 1; Fluorescent Dyes; Freeze Fracturing; Humans; Microscopy, Electron; Microscopy, Fluorescence; Phospholipids; Platelet Aggregation; Pyrimidinones