Macrophage Polarisation Markers in the Development of Diabetic Kidney Disease — ASN Events
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  3. Macrophage Polarisation Markers in the Development of Diabetic Kidney Disease

Macrophage Polarisation Markers in the Development of Diabetic Kidney Disease (#88)

Rebecca Seehoo 1 , Christine Yee 1 , Surya Sutanto 1 , Babu Raja Maharjan 1 , Ali Rezaeizadeh 1 , Danqing Min 1 2 , Susan McLennan 1 2
  1. Greg Brown Diabetes and Endocrinology Research Laboratory, Sydney Medical School, Charles Perkins Centre, Bosch Institute, University of Sydney, Camperdown
  2. Dept of Endocrinology, RPA Hospital, Sydney, Australia

Diabetic kidney disease (DKD), the leading cause of end stage renal disease, is associated with macrophage infiltration. Macrophages are heterogeneous, the pro-fibrotic and inflammatory phenotype (M1) has been correlated with DKD severity. Little is known regarding the relationship between macrophage phenotype and onset of DKD and whether the anti-inflammatory macrophage phenotype (M2) is also altered in DKD has not been extensively studied. In this study we investigated at the gene and protein level the relationship between macrophage phenotype and development of DKD.

Diabetes (DM) was induced in 6 week old C57BL/6 mice (n=6-10/group) by streptozotocin (65mg/kg, 3 doses) and confirmed by blood glucose > 15mmol/L. Kidneys were harvested at 10, 20 and 30 weeks for measurement of fibrotic markers (fibronectin, and collagens I and IV), macrophages F4/80 and phenotype markers (for M1: CD11c and CD64 and for M2: CD206 and CD163) by qRT-PCR.  Flow cytometry was used to quantitate kidney percentage (%) of macrophages (F4/80+) and the %M1 (F4/80+Ly6C+) and %M2 (F4/80+CD163+) populations at 20 and 30weeks. Age matched non diabetic animals acted as control (CON). 

In DM increased expression of F4/80, CD64 and CD206 from 10 weeks onward (all P<0.05) preceded an increase in expression of fibrosis markers which was apparent at 30weeks (all P<0.05). However not all macrophage markers followed the same pattern. CD163 was increased only at 30 weeks (by 2.2-fold, P<0.05) and CD11c was unchanged. By flow, DM tended to decrease the % F4/80+ macrophages. Within this population at 20 weeks the %F4/80+Ly6C+ cells were decreased (P<0.05). In contrast at 30 weeks %F4/80+Ly6C+ cells were increased (P<0.05) and %F4/80+CD163+ were not different to CON.

This data suggests that alteration in macrophage phenotype precede changes in fibrosis markers. This data was confirmed albeit using different macrophages markers by flow cytometry. The relationship between the change in macrophage phenotype measured by gene and protein requires further investigation.  Supported by Diabetes Australia Research Trust.