Corneal Confocal Microscopy Detects Neuropathy in Subjects With Impaired Glucose Tolerance

• Published in: Diabetes care Vol. 37; no. 9; pp. 2643 - 2646
• Main Authors: Asghar, Omar, Petropoulos, Ioannis N., Alam, Uazman, Jones, Wendy, Jeziorska, Maria, Marshall, Andrew, Ponirakis, Georgios, Fadavi, Hassan, Boulton, Andrew J.M., Tavakoli, Mitra, Malik, Rayaz A.
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01.09.2014
• Subjects: Adult; Aged; Biological and medical sciences; Biopsy; Case-Control Studies; Cornea - pathology; Cranial nerves. Spinal roots. Peripheral nerves. Autonomic nervous system. Gustation. Olfaction; Density; Diabetes; Diabetes. Impaired glucose tolerance; Diabetic neuropathy; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Follow-Up Studies; Glucose - metabolism; Glucose Intolerance - complications; Glucose Intolerance - pathology; Humans; Male; Medical sciences; Metabolic diseases; Microscopy; Microscopy, Confocal - methods; Middle Aged; Nerve Fibers - pathology; Nervous system (semeiology, syndromes); Neurologic Examination; Neurology; Novel Communications in Diabetes; Pain Measurement; Peripheral Nervous System Diseases - diagnosis; Peripheral Nervous System Diseases - etiology; Endocrinopathy; Eye; Human; Visual system; Nervous system diseases; Cornea; Nutrition; Metabolic diseases; Confocal microscopy; Neuropathy; Impaired glucose tolerance; Endocrinology
• ISSN: 0149-5992; 1935-5548; 1935-5548
• DOI: 10.2337/dc14-0279

Impaired glucose tolerance (IGT) represents one of the earliest stages of glucose dysregulation and is associated with macrovascular disease, retinopathy, and microalbuminuria, but whether IGT causes neuropathy is unclear. Thirty-seven subjects with IGT and 20 age-matched control subjects underwent a comprehensive evaluation of neuropathy by assessing symptoms, neurological deficits, nerve conduction studies, quantitative sensory testing, heart rate variability deep breathing (HRVdb), skin biopsy, and corneal confocal microscopy (CCM). Subjects with IGT had a significantly increased neuropathy symptom profile (P < 0.001), McGill pain index (P < 0.001), neuropathy disability score (P = 0.001), vibration perception threshold (P = 0.002), warm threshold (P = 0.006), and cool threshold (P = 0.03), with a reduction in intraepidermal nerve fiber density (P = 0.03), corneal nerve fiber density (P < 0.001), corneal nerve branch density (P = 0.002), and corneal nerve fiber length (P = 0.05). No significant difference was found in sensory and motor nerve amplitude and conduction velocity or HRVdb. Subjects with IGT have evidence of neuropathy, particularly small-fiber damage, which can be detected using skin biopsy and CCM.