TIMP3 and idiopathic pulmonary arterial hypertension: TIMP-3 protein levels, determined by protein blotting, were increased, on average, 2.3 fold in IPAH relative to normal lung tissue for both the 24 kDa unglycosylated and the 30 kDa glycosylated forms of TIMP-3 (significantly for the 30 kDa isoform, P < 0.05; but not significantly for the 24 kDa isoform P < 0.08) (Fig 2C).