Israel Medical Association Journal

Since both major forms of diabetes involve inadequate function of pancreatic beta cells, intensive research is ongoing to better understand how beta cells perform their complex role of secreting the hormone insulin in response to physiologic needs. Identification and characterization of pancreatic transcription factors has revealed that they play a crucial role not only in maintenance of mature beta-cell function but also at multiple stages in pancreatic development. Furthermore, recent reports have revealed their potential to convert non-beta cells into insulin-producing cells, which in some cases can function to ameliorate diabetes in experimental animals. The ability to translate these successes to the clinic will require a detailed mechanistic understanding of the molecular basis of action of these proteins. Specific gene regulation in beta cells involves the action of multiple transcription factors recruited to the promoter and functioning synergistically to activate transcription, in part through recruitment of co-activator proteins and components of the basal transcriptional machinery. In addition, the process involves modification of chromatin structure, the details of which are beginning to be elucidated. Our ability to modulate gene expression patterns may lead to developing ways to provide an unlimited supply of functional beta cells for transplantation, permitting a dramatic improvement in therapeutic options for diabetes.

Intractable forms of autoimmune diseases follow a rapid course, with a significantly shortened life expectancy sometimes comparable to that of malignant diseases. Immunoablative therapy, including high dose cytotoxic agents and hematopoietic autologous stem cell rescue, was recently introduced as an aggressive approach to treat autoimmune diseases that have a rapid course and are resistant to conventional therapy. The most frequent indication for this type of treatment is multiple sclerosis, seconded by systemic sclerosis. The results of immunoablative treatment with documented responses in both diseases are encouraging. The data are mature enough to begin comparative randomized studies of immunoablative versus conventional treatment to validate the benefit of the aggressive approach. A randomized trial involving SSc[1] was recently launched (ASTIS) and a trial involving MS[2] is under preparation. Considerably less experience with immunoablative treatment has been gained in systemic lupus erythematosus, rheumatoid arthritis, and other disorders with an autoimmune pathophysiology. Autologous hematopoietic stem cell transplantation in humans offers more long-lasting immunosuppression than reeducation of lymphocytes. In fact, allogeneic transplantation may replace the whole immune system. However, this attractive approach is still associated with considerable morbidity and mortality and is not yet justified for treatment of automimmune diseases. Non-myeloablative allogeneic transplantation and sub-myeloblative high dose cyclophosphamide without stem cell support are alternative approaches that could be explored in pilot studies.

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The future promises good news for the treatment of systemic lupus erythematosus, some of which can already be foreseen. Increased knowledge on genes that participate in the predis­position, pathogenesis, pharmacogenetics of, and protection against this disease may permit intervention at this level. Also, better understanding about the role of sex hormones has allowed trials of weak androgens or prolactin inhibitors. New immunomodulators or i mmunosuppresors may enable more precise treatment at the immunoregulatory level, and greater knowledge on the disturbance of circuits has already provided hints and even allowed trials of anti-interleukin-10 antibodies, an IL-10 decreasing agent, tolerance-induction strategies or intervention at the level of T cell co-stimulation, as well as immune ablation with subsequent stem cell transplantation. Autoantibodies can be removed, controlled by means of anti­idiotypes, which are blocked from reaching their target antigen or uncoupled from the tissues they have reached. All these treatment strategies will gradually become decanted in order to achieve the optimal treatment of SEE, which may turn out to be its cure.