Immune Depletion With Cellular Mobilization Imparts Immunoregulation and Reverses Autoimmune Diabetes in Nonobese Diabetic Mice

Abstract

OBJECTIVEThe autoimmune destruction of β-cells in type 1 diabetes results in a loss of insulin production and glucose homeostasis. As such, an immense interest exists for the development of therapies capable of attenuating this destructive process through restoration of proper immune recognition. Therefore, we investigated the ability of the immune-depleting agent antithymocyte globulin (ATG), as well as the mobilization agent granulocyte colony–stimulating factor (GCSF), to reverse overt hyperglycemia in the nonobese diabetic (NOD) mouse model of type 1 diabetes.RESEARCH DESIGN AND METHODSEffects of each therapy were tested in pre-diabetic and diabetic female NOD mice using measurements of glycemia, regulatory T-cell (CD4+CD25+Foxp3+) frequency, insulitis, and/or β-cell area.RESULTSHere, we show that combination therapy of murine ATG and GCSF was remarkably effective at reversing new-onset diabetes in NOD mice and more efficacious than either agent alone. This combination also afforded durable reversal from disease (>180 days postonset) in animals having pronounced hyperglycemia (i.e., up to 500 mg/dl). Additionally, glucose control improved over time in mice subject to remission from type 1 diabetes. Mechanistically, this combination therapy resulted in both immunological (increases in CD4-to-CD8 ratios and splenic regulatory T-cell frequencies) and physiological (increase in the pancreatic β-cell area, attenuation of pancreatic inflammation) benefits.CONCLUSIONSIn addition to lending further credence to the notion that combination therapies can enhance efficacy in addressing autoimmune disease, these studies also support the concept for utilizing agents designed for other clinical applications as a means to expedite efforts involving therapeutic translation.

Intradermal α1-antitrypsin therapy avoids fatal anaphylaxis, prevents type 1 diabetes and reverses hyperglycaemia in the NOD mouse model of the disease

“…The rationale of using G-CSF in this study was to employ its immunoregulatory properties, including its ability to mobilise regulatory T cells, induce tolerogenic dendritic cells and shift cytokine phenotype from T-helper type 1 to type 2 [13,14]. Previously we demonstrated that G-CSF enhanced the efficacy of ATGmediated reversal of type 1 diabetes in the NOD mouse model, but as in the present study G-CSF monotherapy did not prevent or reverse disease [4]. Unfortunately, in the present study, we did not observe an enhancing effect when G-CSF was used in combination with AAT.…”

“…Histology and immunohistochemistry Insulitis was evaluated and scored on pancreatic sections stained with haematoxylin and eosin, as described previously [4][5][6]. Briefly, the degree of lymphocytic infiltration in each islet was scored according to the following scale: 0, none; 1, peri-islet infiltrates; 2, <50% intra-islet infiltrates; 3, >50% intra-islet infiltrates.…”

“…Briefly, the degree of lymphocytic infiltration in each islet was scored according to the following scale: 0, none; 1, peri-islet infiltrates; 2, <50% intra-islet infiltrates; 3, >50% intra-islet infiltrates. Insulin immunohistochemistry was performed as previously described [4][5][6]. Fractional insulin area was determined from whole digital slide scans using a positive pixel count algorithm (Spectrum, Aperio, Vista, CA, USA).…”

“…Due to the pathogenic complexity of this disease, development of an effective method for late prevention or reversal post-onset of the disorder has been remarkably challenging [1]. Although recent studies have shown promising results in terms of reversing type 1 diabetes, many of these treatments can lead to detrimental side effects [2][3][4]. As such, the exploration of therapies with more tolerable adverse event profiles is urgently needed.…”

“…G-CSF has successfully prevented both the onset of disease in the NOD mouse and cyclophosphamide-mediated acceleration of diabetes [15,16]. Parker et al have recently shown that G-CSF enhances the long-term reversal of diabetes afforded by murine antithymocyte globulin (ATG) [4]. To determine if the combination of G-CSF and hAAT would enhance the protective effect of hAAT alone on type 1 diabetes prevention and reversal, we included G-CSF as a second drug in the present study.…”