Human Subcutaneous Inflammatory Response to Glucose Sensors

Eighteen Type 1 DM patients are going to be included. Primary Objectives

• To define the intra-individual and inter-individual variability of the macrophage count around the sensor
• To assess whether there is a relationship between the number of macrophages, fibrosis and MARD of the MCG registry.

Secondary Objectives

To describe the histology of tissue response. This description will include:

• HE stain: cell types, arrangement, vascular structures, signs of hemorrhage-clot. Giemsa stain: mast cells. Masson's trichrome stain: str. vascular.
• Immunohistochemistry: Vascular assessment, characterization of macrophages

Each patient will have 1 glucose sensor inserted in the non-dominant arm. During the useful life of the sensor (10), a minimum of 4 capillary blood glucose determinations/day will be performed The sensor has a length of 8 mm and a diameter of 0.4 mm. All the necessary material will be provided, including a control diary to help the patient remember to carry out the self-control and set its time distribution.

On the last day of sensor use, it will be removed and a 4-mm punch skin biopsy will be performed 5 minutes later.

Tissue samples will be fixed in 4% formaldehyde solution, paraffin blocks made and sectioned. The resulting samples will be stained Semiquantitative determination of lymphocytes, neutrophils, mast cells, macrophages will be performed; fibrin, fibrosis, vascular proliferation and karyorrhexis

In all cases, a quantitative immunohistochemical study will be performed with x40 field counting with photographs and grid (Dako omnis with envision system) for:

Macrophages

The monitor-glucometer will be recovered for download and study of the record. The interstitial glucose - blood pairs will be made with those recorded but not used for callibration.

Glucose sensor values and insulin doses will be recover from tha medical application

Inclusion criteria

• 1. Type 1 diabetes of more than 6 months duration, confirmed by positivity for Ab antiGAD 65 2. Be a regular user of a continuous glucose monitoring system 2. To Understand the proposed protocol and acceptance of participation.

Exclusion criteria

• Treatment with drugs that could potentially modify the inflammatory response during the 10 days prior to surgery (non-steroidal anti-inflammatory drugs or corticosteroids, antioxidants or platelet antiaggregants).