T BLOCK1, K SOURRIS1, A KHAN1, P KANTHARIDIS1, J JHA1, M COOPER1, J SHAW2, K JANDELEIT-DAHM1,3
1Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia, 2Department of Cardiology, Alfred Health, Melbourne, Australia, 3Leibniz Chair, German Diabetes Centre, Leibniz Centre for Diabetes Research, Heinrich Heine University, Dusseldorf, Germany
Aim: To link the expression of human NADPH oxidase 5 (NOX5) in circulating peripheral blood mononuclear cells (PBMCs) to disease state in patients with diabetes, particularly in those with chronic kidney disease (CKD).
Background: Oxidative stress derived from NOX5 plays a critical role in the development of diabetic vascular and renal disease. NOX5 expression has been demonstrated in atherosclerotic plaques and in kidney biopsies of diabetic patients, making it an attractive therapeutic target.
Methods: 46 males aged 33-83 years underwent elective or emergency coronary angiography/angioplasty at the Alfred Hospital Catheter Laboratory. PBMCs were isolated from whole blood and processed for flow-cytometry to measure NOX5 protein and gene expression by qPCR. In vitro, human macrophages (THP-1) were incubated in low (5mM) and high glucose (25 mM). NOX5 expression and inflammatory markers were measured by qPCR.
Results: NOX5 protein expression in PBMCs was primarily driven by expression in monocytes (CD 45+/CD14+ cells) and was increased in diabetic and non-diabetic patients with CKD versus without CKD (29.5±4.4 vs 18.2±1.9 AU; p=0.0093) and in diabetic patients with CKD versus without CKD (28.4±4.3 vs 16.5±2.2 AU; p=0.03). NOX5 mRNA was upregulated 4-fold in patients with CKD vs without CKD irrespective of diabetes (p=0.018). In vitro, there was a 2-fold increase in NOX5, TNF-alpha and Interleukin-6 expression in THP-1 cells exposed to high glucose.
Conclusion: CKD is a key factor for increased NOX5 protein and gene expression in circulating PBMCs in patients irrespective of diabetes. This is consistent with NOX5 accelerating renal inflammation and fibrosis. Measurement of NOX5 in PBMCs may serve as a valuable prognostic biomarker.
Dr Tomasz Block is a Basic Physician Trainee at Eastern Health, Victoria. He completed an undergraduate Biomedical Science degree at the University of Melbourne, followed by an Honours degree at the Baker Heart and Diabetes Institute. He then went on to complete postgraduate Medicine at Deakin University and is currently an Adjunct Research Associate in the Department of Diabetes, Monash University, Melbourne. Tomasz is involved in several research projects and is particularly passionate about translational research in the field of cardiometabolic disease.