OBJECTIVE Transforming growth factor-β (TGF-β) is a potent inducer of extracellular matrix production and of fibrogenesis and has been associated with the occurrence of diabetic micro- and macrovascular complications. Our aim was to determine whether circulating levels of TGF-β1 are altered in NIDDM and, if so, whether they are correlated with blood glucose and show an association with diabetic complications.

RESEARCH DESIGN AND METHODS Plasma levels of TGF-β1 were determined by enzyme-linked immunosorbent assay in 44 NIDDM patients and 28 control subjects of comparable age and weight and were correlated with parameters of metabolic control and the occurrence of micro- and macrovascular complications.

RESULTS TGF-β1 was significantly elevated in NIDDM (7.9 ± 1.0 ng/ml), as compared with control subjects (3.1 ± 0.4 ng/ml, P < 0.001) and correlated with glycosylated hemoglobin (r² = 0.42; P < 0.001). Thrombocyte levels of TGF-β1 were similar in control subjects (54 ± 7 pg/ml, n = 16) and diabetic patients (61.6 ± 18 pg/ml, n = 13; P = 0.357). Elevated TGF-β1 levels were associated with retinopathy and neuropathy.

CONCLUSIONS We conclude that plasma levels of TGF-β1 are elevated in NIDDM patients and may be related to average blood glucose. Preliminary data suggest that they may contribute to the occurrence of diabetic complications.