In SI carcinoid tumor patients with documented fibrosis, TMA analysis demonstrated higher CTGF immunostaining (AQUA Score: 92 +/- 8; P < 0.05), as well as elevated TGFbeta1 (90.6 +/- 4.4, P < 0.05).
CTGF was highly expressed in tubuloepithelial cells of allografts, along with alpha-smooth muscle actin, a marker of myofibroblasts, and transcriptionally associated with other markers of fibrosis.
Thus the constitutive overexpression of CTGF by fibroblasts present in fibrotic lesions would be expected to directly contribute to chronic, persistent fibrosis.
Therefore, the cooperation between CTGF and IGF-I might be involved in glucose-induced matrix accumulation in tubulointerstitial fibrosis and might contribute to the pathogenesis of diabetic nephropathy.