32 Parameter Mass Cytometry Reveals Changes to Circulating and Bone Marrow Immune Cells in Streptozotocin-induced Diabetic Mice.

Diabetes mellitus (DM) is a metabolic disorder of chronic hyperglycaemia which arises from interactions between genetic, epigenetic, environmental and behavioural determinants. Inflammation plays a vital role in diabetes pathogenesis. Complications derived from diabetes result from an imbalance towards pro-inflammatory immune responses in target organs. Paradoxically to the pro-inflammatory environment, people living with DM are considered immunocompromised, with a complete immune profile yet to be created and still being studied. This profile is urgently needed to develop strategies towards treatment optimisation. Using the streptozotocin-induced diabetic (STZ-D) mouse and 32 parameter mass cytometry, differences between diabetic mice and normoglycaemic controls were identified. An organised and replicable high dimensional data analysis strategy using the tSNE algorithm, was developed to visualise differences between STZ-D and control groups. Our main finding was the significant increase in circulating B220+CD19+ cells in both 5 and 15 weeks STZ-D groups when compared to controls. There is an inverse correlation between circulating cytotoxic T cells and blood glucose levels (BGL). Circulating Siglec-F+ cells (eosinophils), also significantly decrease as BGL increases. Bone marrow differences between STZ-D and controls show changes in myeloid derived cells which can be related to the proinflammatory environment in which diabetic microangiopathy develops. Mass cytometry dramatically expanded our discovery scope, revealing potentially new cellular players in STZ-D-induced inflammation. Using new gating strategies together with high dimensional data tools like tSNE directs time and resources towards the production of significant findings. Characterising cell subsets allows the identification of progression markers and provides personalised prevention and treatment strategies