Corneal Confocal Microscopy Detects Early Nerve Regeneration in Diabetic Neuropathy After Simultaneous Pancreas and Kidney Transplantation

  1. Rayaz A. Malik1
  1. 1Division of Cardiovascular Medicine, University of Manchester and Wellcome Trust Clinical Research Facility, Manchester, U.K.
  2. 2Transplantation Unit, Manchester Royal Infirmary, Central Manchester University Hospitals Foundation Trust, Manchester, U.K.
  3. 3Tissue Injury and Repair Group, School of Medicine, The University of Manchester, U.K.
  4. 4Department of Clinical Neurophysiology, Manchester Royal Infirmary, Central Manchester University Hospitals Foundation Trust, U.K.; and
  5. 5Institute of Health and Biomedical Innovation and School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia.
  1. Corresponding author: Rayaz A. Malik, rayaz.a.malik{at}man.ac.uk.

Abstract

Diabetic neuropathy is associated with increased morbidity and mortality. To date, limited data in subjects with impaired glucose tolerance and diabetes demonstrate nerve fiber repair after intervention. This may reflect a lack of efficacy of the interventions but may also reflect difficulty of the tests currently deployed to adequately assess nerve fiber repair, particularly in short-term studies. Corneal confocal microscopy (CCM) represents a novel noninvasive means to quantify nerve fiber damage and repair. Fifteen type 1 diabetic patients undergoing simultaneous pancreas–kidney transplantation (SPK) underwent detailed assessment of neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy, corneal sensitivity, and CCM at baseline and at 6 and 12 months after successful SPK. At baseline, diabetic patients had a significant neuropathy compared with control subjects. After successful SPK there was no significant change in neurologic impairment, neurophysiology, QST, corneal sensitivity, and intraepidermal nerve fiber density (IENFD). However, CCM demonstrated significant improvements in corneal nerve fiber density, branch density, and length at 12 months. Normalization of glycemia after SPK shows no significant improvement in neuropathy assessed by the neurologic deficits, QST, electrophysiology, and IENFD. However, CCM shows a significant improvement in nerve morphology, providing a novel noninvasive means to establish early nerve repair that is missed by currently advocated assessment techniques.

  • Received May 3, 2012.
  • Accepted July 5, 2012.

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  1. Diabetes vol. 62 no. 1 254-260
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