Abnormally high expression of Gremlin-1 is closely correlated with idiopathic pulmonary fibrosis (IPF) [11,12] and human renal diseases such as diabetic nephropathy (DN) [13], pauci-immune glomerulonephritis [14,15] and chronic allograft nephropathy [15]. This evidence concerns the gene GREM1 and idiopathic pulmonary fibrosis.