Immunohistochemical study of monocyte chemoattractant protein-1 in the pancreas of NOD mice following cyclophosphamide administration and during spontaneous diabetes

T cell populations in the pancreatic lymph node naturally and consistently expand and contract in NOD mice as disease progresses

Nonobese diabetic (NOD) mice develop spontaneous autoimmune Type 1 diabetes (T1D) that results from the destruction of insulin secreting β cells by diabetogenic T cells. The activation of autoreactive T cells occurs in the pancreatic lymph nodes (PLN) from where effector T cells migrate to the pancreas. This study was designed to explore whether T cell populations in the NOD PLN expand in a predictable and reproducible way during disease progression. Complementary determining region (CDR) 3 length spectratype analysis of 19 TCR Vβ families was used to identify the relative frequency of T populations in PLN of 4 and 10 week old NOD mice and mice at T1D onset. Significant and highly reproducible changes in specific T cell populations were detected in 14 of Vβ families tested at all stages of disease. However, of these, the CDR3 spectratype of only four Vβ families was significantly more perturbed at T1D onset than in 10 week old mice. Intriguingly, when diabetes was induced in 10 week old mice with cyclophosphamide (CYP) the same four Vβ families, Vβ5.1, Vβ9, Vβ10, and Vβ15, were again significantly more perturbed than in the untreated non-diabetic age matched mice. Taken together the data show that while T cell responses in PLN of NOD mice are heterogeneous, they are ordered and consistent throughout disease development. The finding that within this heterogeneous response four Vβ families are significantly more perturbed in diabetic mice, whether spontaneous or induced, strongly suggests their selection as part of the disease process.

An immunohistochemical study on the distribution and frequency of T regulatory cells in pancreatic islets of NOD mice during various stages of spontaneous and cyclophosphamide-accelerated diabetes

OBJECTIVES

To determine if there is an abrupt change in the frequency of intraislet T regulatory (Treg) cells in female nonobese diabetic (NOD) mice preceding and following spontaneous diabetes and during cyclophosphamide-accelerated disease.

METHODS

The frequency of intraislet CD4-positive Treg cells was analyzed between days 21 and 250, at onset, and at 1, 2, and 3 weeks of diabetes by dual-label immunohistochemistry. Tissues were also analyzed between days 0 and 14 after injection of cyclophosphamide or diluent.

RESULTS

In the spontaneous group, intraislet Treg cells were first observed on day 30 in CD4 T cells and increased from day 45. There was no statistical difference in the frequency of Treg cells in nondiabetic NOD mice on days 45, 60, and 90. A sustained frequency at and after 1, 2, and 3 weeks of diabetes was also observed. In the cyclophosphamide group, there was a sharp decline in the frequency of Treg cells on day 4, which remained lower on day 7 but increased by days 11 and 14.

CONCLUSIONS

During spontaneous diabetes and after onset, the frequency of intraislet CD4-positive Treg cells remains unchanged. They may possess diminished immunoregulatory function and thus unable to counteract the increasing tempo of immune-mediated beta-cell destruction.

Short-term IL-1beta blockade reduces monocyte CD11b integrin expression in an IL-8 dependent fashion in patients with type 1 diabetes

OBJECTIVE

Interleukin 1-beta (IL-1beta) is a major inflammatory cytokine. Blockade of the IL-1beta pathway is therapeutically efficacious in type 2 diabetes, but the mechanistic effects on the immune system are incompletely understood.

RESEARCH DESIGN

We administered an IL-1 receptor antagonist, anakinra, to 7 type 1 diabetes patients in order to investigate the immunologic and metabolic effects of this drug. Mechanistic assays were performed before and after drug administration.

RESULTS

A novel signature was observed, with reduced serum interleukin 8 (IL-8) levels and reduced CD11b integrin expression on monocytes associated with increased CXCR1 expression.

CONCLUSIONS

This set of linked phenotypes suggests that blockade of the IL-1beta pathway results in the reduced ability of mononuclear cells to traffic to sites of inflammation. Mechanistic studies from large scale trials using IL-1 blockade in type 1 diabetes should focus on changes in monocyte trafficking and the IL-8 pathway.

Monocyte chemoattractant protein-1 promoter -2518 polymorphism is associated with post-challenge insulin and glucose levels in non-diabetic Japanese subjects

We investigated that the association of MCP-1 polymorphism at position -2518 with insulin sensitivity and insulin secretion by measuring the fasting and post-challenge glucose and insulin levels during 75g OGTT in 409 non-diabetic Japanese subjects. The blood sampling was performed before glucose loading and after 30 and 120 min. Polymorphism was evaluated by PCR-RFLP method by genomic DNA isolated from peripheral blood leukocytes. The genotype distribution was 44.8% for G/G, 46.0% for G/A and 9.2% for A/A. The plasma glucose levels were significantly increased in A/A as compared to G/G (p<0.05), but it was not compared with G/A at 120 min. The serum insulin levels were significantly increased in A/A as compared to G/A (p<0.05) or G/G (p<0.05) at 30 min. Moreover, the serum insulin levels in A/A were significantly increased compared with G/A (p<0.02) or G/G (p<0.005) at 120 min. Elevation in post-challenge glucose (120 min) and insulin levels (30 and 120 min) suggests that reduced insulin sensitivity during glucose loading occurs in subjects with A/A polymorphism. The present study demonstrates that the A/A polymorphism of the MCP-1 gene at position -2518 is associated with insulin resistance during glucose loading in non-diabetic Japanese subjects.