Corneal Confocal Microscopy Detects Early Nerve Regeneration After Pancreas Transplantation in Patients with Type 1 Diabetes.

Abstract

OBJECTIVE - Corneal confocal microscopy is a rapid, non invasive clinical examination technique which quantifies small nerve fibre pathology. We have employed it to assess the neurological benefits of pancreas transplantation in Type 1 diabetic patients.

RESEARCH DESIGN AND METHODS - 20 patients with Type 1 diabetes undergoing simultaneous pancreas and kidney transplantation (SPK) and 15 control subjects underwent assessment of corneal sensitivity and small nerve fibre morphology using corneal confocal microscopy.

RESULTS - Corneal sensitivity (1.54 ∓ 0.28 v 0.77 ∓ 0.02, P<0.0001), nerve fibre density (NFD) (13.8 ∓ 2.1 v 42 ∓ 3.2, P<0.0001), nerve branch density (NBD) (4.04 ∓ 1.5 v 26.7 ∓ 2.5, P<0.0001) and nerve fibre length (NFL) (2.23 ∓ 0.2 v 9.69 ∓ 0.7, P<0.0001) were significantly reduced and nerve fibre tortuosity (NFT) (15.7 ∓ 1.02 v 19.56 ∓ 1.34, P=0.04) was increased in diabetic patients prior to pancreas transplantation. Six months after SPK, 15 patients underwent a second assessment and showed a significant improvement in NFD (18.04∓1.48 v 9.25 ∓1.87, P= 0.001) and NFL (3.60 ∓ 0.33 v 1.84 ∓ 0.33, P=0.002) with no change in NBD (1.38 ∓ 0.74 v 1.38 ∓ 1.00, P=1.0 ), NFT (15.58 ∓ 1.20 v 16.30 ∓ 1.19, P=0.67) or corneal sensitivity (1.23 ∓0.39 v 1.54∓0.42, P=0.59).

CONCLUSIONS - Despite marked nerve fibre damage in Type 1 diabetic patients undergoing pancreas transplantation, small fibre repair can be detected within 6 months of pancreas transplantation using corneal confocal microscopy. Corneal confocal microscopy is a novel non-invasive clinical technique to assess the benefits of therapeutic intervention in human diabetic neuropathy.