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

doi:10.2337/dc07-0870

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

¹Transplant Unit, Manchester Royal Infirmary, Manchester, U.K
²Division of Cardiovascular Medicine, University of Manchester and Manchester Royal Infirmary, Manchester, U.K
³Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia

Address correspondence and reprint requests to Dr. R.A. Malik, Division of Cardiovascular Medicine, University of Manchester, Manchester, M13 9NT, U.K. E-mail: rayaz.a.malik{at}man.ac.uk

Abstract

OBJECTIVE—Corneal confocal microscopy (CCM) is a rapid, noninvasive, clinical examination technique that quantifies small nerve fiber pathology. We have used it to assess the neurological benefits of pancreas transplantation in type 1 diabetic patients.

RESEARCH DESIGN AND METHODS—In 20 patients with type 1 diabetes undergoing simultaneous pancreas and kidney transplantation (SPK) and 15 control subjects, corneal sensitivity was evaluated using noncontact corneal esthesiometry, and small nerve fiber morphology was assessed using CCM.

RESULTS—Corneal sensitivity (1.54 ± 0.28 vs. 0.77 ± 0.02, P < 0.0001), nerve fiber density (NFD) (13.8 ± 2.1 vs. 42 ± 3.2, P < 0.0001), nerve branch density (NBD) (4.04 ± 1.5 vs. 26.7 ± 2.5, P < 0.0001), and nerve fiber length (NFL) (2.23 ± 0.2 vs. 9.69 ± 0.7, P < 0.0001) were significantly reduced, and nerve fiber tortuosity (NFT) (15.7 ± 1.02 vs. 19.56 ± 1.34, P = 0.04) was increased in diabetic patients before pancreas transplantation. Six months after SPK, 15 patients underwent a second assessment and showed a significant improvement in NFD (18.04 ± 10.48 vs. 9.25 ± 1.87, P = 0.001) and NFL (3.60 ± 0.33 vs. 1.84 ± 0.33, P = 0.002) with no change in NBD (1.38 ± 0.74 vs. 1.38 ± 1.00, P = 1.0), NFT (15.58 ± 1.20 vs. 16.30 ± 1.19, P = 0.67), or corneal sensitivity (1.23 ± 0.39 vs. 1.54 ± 00.42, P = 0.59).

CONCLUSIONS—Despite marked nerve fiber damage in type 1 diabetic patients undergoing pancreas transplantation, small fiber repair can be detected within 6 months of pancreas transplantation using CCM. CCM is a novel noninvasive clinical technique to assess the benefits of therapeutic intervention in human diabetic neuropathy.

Footnotes

Published ahead of print at http://care.diabetesjournals.org on 10 July 2007. DOI: 10.2337/dc07-0870.

A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

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- Accepted July 2, 2007.
- Received May 4, 2007.
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