Somatic and autonomic diabetic neuropathy contribute to 87% of these amputations

Somatic and autonomic diabetic neuropathy contribute to 87% of these amputations.2It is now appreciated that there are different forms of neuropathy in diabetes.1Damage occurs to both large, myelinated nerve fibers and small, unmyelinated fibers (C-fibers). neurovascular function, translating into improved symptoms as well as sensory nerve function. The simultaneous improvement of selective metabolic indices may play a role in this effect, but this remains to be decided. Keywords:diabetic neuropathy, skin blood flow, skin biopsy, diabetes == Introduction == The leading cause of nontraumatic extremity amputation is usually complications of diabetes, with over 96,000 amputations per year.1Neuropathy associated with diabetes predisposes to pain, numbness, ulceration, contamination, gangrene, and amputation. Somatic and autonomic diabetic neuropathy contribute to 87% of these amputations.2It is now appreciated that there are different forms of neuropathy in diabetes.1Damage occurs to both large, myelinated nerve fibers and small, unmyelinated fibers (C-fibers). The small, unmyelinated C-fibers subserve thermal and pain perception, and the small autonomic fibers affect sweating and vascular control.3Damage to small, unmyelinated C-fibers has the best impact on survival and quality of life, producing initial symptoms such as pain, numbness, and anhidrotic skin with disordered skin blood flow (SKBF) predisposing to foot ulcers, infection, gangrene and limb loss.4Diabetic peripheral neuropathy is the primary cause of diabetic ulcers and the most predictive diagnosis for an eventual amputation. Current therapies for diabetic peripheral neuropathy are for symptomatic relief of pain and not for the underlying disorder.58Any addition to the therapeutic armamentarium would be welcome. It has been shown that small fiber neuropathies are quantifiable with newer assessments of C-fiber integrity that include quantitative steps of SKBF and corneal confocal microscopy,911quantification of intraepidermal nerve fibers (IENF),1216and quantitative sensory testing (QST).17Heat- induced vasodilation (44C), is reduced in subjects with impaired glucose tolerance, and in type 2 diabetic patients with and without neuropathy.18 We have reported that one of the earliest quantitative sensory abnormalities found in people with diabetic peripheral neuropathy is the impairment of small fiber sensory belief that cosegregates with disordered neurovascular function.19,20Furthermore, there is evidence to suggest that one of the early manifestations of C-fiber dysfunction can be based upon skin biopsies, with measurement of the density of thin, unmyelinated nerve fibers using immunohistochemistry for Protein Gene Product 9.5 (PGP-9.5) as a neuronal marker.12,13,15,16,21,22Since description of the utility of PGP- 9.5 as a marker for IENF in human skin,23it has been used for identification of small nerve fibers in the dermis and epidermis in a range of small fiber neuropathies, including human immunodeficiency computer virus, and idiopathic small fiber and postherpetic neuralgia, among others.13,15,2429In addition, we have now established that there are characteristic changes in DKK2 IENF that distinguish the metabolic syndrome from diabetes.30IENF density was recently given a level A recommendation by the European Federation of the Neurological Societies and the Peripheral Nerve Society as a reliable and efficient technique to confirm the clinical diagnosis of small fiber neuropathy.31The IENF density has been shown to correlate inversely with cold and heat detection thresholds.32A oneyear diet and exercise intervention program in patients with small fiber neuropathy and impaired glucose tolerance led to increased IENF density.33IENF loss is evident early in the CHIR-99021 disease process, declines with increasing neuropathic pain, and can be used as CHIR-99021 an outcome measure in clinical trials.31,33Apart from the one-year trial on diet and exercise,33no drug has been shown to induce C-fiber regeneration. Topiramate, a structurally novel antiepileptic drug, is effective in treatment of various types of epilepsy and prevention of migraine headaches. A sulfamate-substituted derivative ofd-fructose, topiramate has several pharmacologic properties suggesting it may have potential for overcoming the programmed cell death implicated in the pathogenesis of neuropathy.4It enhances gamma aminobutyric acid (GABA) activity by interacting with a nonbenzodiazepine site on GABA receptors, has unfavorable modulatory effects on voltage-activated Na+ channels,34selectively blocks AMPA/kainate glutamate receptors, has unfavorable modulatory effects on L-type high voltage-activated Ca2+channels,35and inhibits the carbonic anhydrase isozymes, CA-I and CA-II.34These multiple mechanisms of action may contribute to its anticonvulsive, CHIR-99021 antinociceptive, and putative neuroprotective properties. There has been no report on the ability of topiramate to influence the structure and function of IENF, although there CHIR-99021 are animal studies to suggest that it may exercise these properties.36,37 Topiramate thus clearly offers an advantage over brokers currently used for neuropathy in as much as it relieves.