HMGB1 and Myocardial fibrosis: Inhibition of HMGB-1 with HMGB-1siRNA reduces ERK and Ets-1 phosphorylation induced by hyperglycaemia.59 Furthermore, HMGB-1 is implicated in myocardial fibrosis.29 Wang and colleagues (2014), demonstrated that HMGB-1 increases TGF-β1 levels in cardiac fibroblasts, enhancing MMP activity, collagen I and collagen III expression.