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Taliyan R, Sharma PL. Protective effect and potential mechanism of Ginkgo biloba extract EGb 761 on STZ-induced neuropathic pain in rats. Phytother Res 2012; 26:1823-9. [PMID: 22422566 DOI: 10.1002/ptr.4648] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 09/14/2011] [Accepted: 01/23/2012] [Indexed: 02/02/2023]
Abstract
Diabetes induced neuropathic pain is recognized as one of the most difficult types of pain to treat with conventional analgaesics. EGb 761 is a standardized extract of Ginkgo biloba that has analgaesic and antiinflammatory properties and modulatory effects on key pain-related molecules. We examined the effect of EGb 761 on streptozotocin (STZ)-induced neuropathic pain behaviours and assessed its mechanism of action. Streptozotocin (20 mg/kg i.p for 5 days) was administered to induce experimental diabetes. Pain hypersensitivity to radiant heat was measured using the Dynamic Plantar Aesthesiometer to test the pain threshold. Diabetic rats exhibited mechanical allodynia and thermal hyperanalgaesia after the third week of STZ injection and concomitantly increased thiobarbituric acid reactive substance and nitric oxide concentration. The antioxidant enzymes level of superoxide dismutase and catalase was markedly reduced in STZ-diabetic rats (p < 0.05). Systemic administration of EGb 761 (25, 50 and 100 mg/kg), starting after the third week following STZ injection, dose-dependently reversed STZ-induced thermal hyperanalgaesia and mechanical allodynia. Moreover, it reduced oxidonitrosative stress and concomitantly restored the level of antioxidant enzymes (p < 0.05) as compared with untreated diabetic rats. These results suggest that EGb 761 attenuated STZ-induced neuropathic pain behaviours by inhibiting oxidative and nitrosative stress and may constitute a new approach for treatment of painful diabetic neuropathy.
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Affiliation(s)
- Rajeev Taliyan
- Department of Pharmacology, ISF College of Pharmacy, Moga-142001, Punjab, India.
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Nishikawa T, Naruse K, Kobayashi Y, Miyajima S, Mizutani M, Kikuchi T, Soboku K, Nakamura N, Sokabe A, Tosaki T, Hata M, Ohno N, Noguchi T, Matsubara T. Involvement of nitrosative stress in experimental periodontitis in diabetic rats. J Clin Periodontol 2012; 39:342-9. [PMID: 22276937 DOI: 10.1111/j.1600-051x.2011.01848.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2011] [Indexed: 11/30/2022]
Abstract
AIM Periodontal disease is highly prevalent and severe in diabetic patients, and is considered one of the diabetic complications. To elucidate how periodontitis progresses in diabetes, we examined an animal model of periodontitis in diabetic rats. MATERIALS AND METHODS Two weeks after the induction of diabetes by streptozotocin, surgical nylon thread was ligated around the cervical portion of the unilateral maxillary second molar to induce periodontitis. Periodontitis was evaluated 2 weeks after the ligation by gingival blood flow, mRNA expressions, Western blot analysis, histological examination and micro CT. RESULTS Ligation-induced severe periodontitis in the diabetic rats, which was apparently shown by the increase of TNF-α and iNOS mRNA expressions and inflammatory cell infiltration in the gingiva and alveolar bone loss. The number of nitrotyrosine, a footprint of nitrosative stress, -positive cells was significantly higher in the periodontitis of the diabetic rats compared with that in the normal rats. Western blot analysis confirmed that the nitrotyrosine was increased in the periodontitis of the diabetic rats. CONCLUSIONS This is the first study to confirm increased nitrosative stress due to periodontitis in diabetic rats. Nitrosative stress may play a crucial role in the exacerbation of periodontitis in diabetic patients.
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Affiliation(s)
- Toru Nishikawa
- Department of Periodontology, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
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Janes K, Neumann WL, Salvemini D. Anti-superoxide and anti-peroxynitrite strategies in pain suppression. Biochim Biophys Acta Mol Basis Dis 2011; 1822:815-21. [PMID: 22200449 DOI: 10.1016/j.bbadis.2011.12.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 12/05/2011] [Accepted: 12/06/2011] [Indexed: 02/08/2023]
Abstract
Superoxide (SO, O(2)·(-)) and its reaction product peroxynitrite (PN, ONOO(-)) have been shown to be important in the development of pain of several etiologies. While significant progress has been made in teasing out the relative contribution of SO and PN peripherally, spinally, and supraspinally during the development and maintenance of central sensitization and pain, there is still a considerable void in our understanding. Further research is required in order to develop improved therapeutic strategies for selectively eliminating SO and/or PN. Furthermore, it may be that PN is a more attractive target, in that unlike SO it has no currently known beneficial role. Our group has been at the forefront of research concerning the role of SO and PN in pain, and our current findings have led to the development of two new classes of orally active catalysts which are selective for PN decomposition while sparing SO. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.
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Affiliation(s)
- Kali Janes
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, MO 63104, USA
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Taliyan R, Sharma PL. Possible mechanism of protective effect of thalidomide in STZ-induced-neuropathic pain behavior in rats. Inflammopharmacology 2011; 20:89-97. [PMID: 22179948 DOI: 10.1007/s10787-011-0106-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 11/29/2011] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Diabetes-induced neuropathic pain is recognized as one of the most difficult type of pain to treat and conventional analgesics are well known to be partially effective or associated with potential toxicity. Recently, it has been demonstrated that thalidomide, besides its teratogenic potential, reduced chronic pain in an SNL experimental pain model. OBJECTIVE The present study was designed to investigate the effect of thalidomide on streptozotocin (STZ)-induced neuropathic pain in rats. MATERIALS AND METHODS Streptozotocin (20 mg/kg, i.p, daily × 4 days) was administered to induce diabetes in the rats. Nociceptive latency was measured using tail-flick and paw-withdrawal test. Thermal hyperalgesia and mechanical allodynia were measured using planter test and dynamic aesthesiometer (Ugo-Basile, Italy), respectively. Urinary and serum nitrite concentration was estimated using Greiss reagent method. Spleen homogenate supernatant was prepared from spleen of 28th day diabetic rats and administered to normal rats (400 ul, i.v) daily for 28 days. RESULTS Pain threshold progressively decreased in STZ-treated rats, as compared with control rats. 3 weeks after induction of diabetes, the rat exhibited thermal hyperalgesia and mechanical allodynia. The analgesic effect of morphine (8 mg/kg, s.c.) was significantly decreased in both diabetic and in SHS-treated non-diabetic rats. Administration of thalidomide (25 and 50 mg/kg, i.p), a TNF-α inhibitor, significantly prevented hyperglycemia-induced thermal hyperalgesia and mechanical allodynia and also attenuated the increase in serum and urinary nitrite concentration, as compared with untreated diabetic rats. Also, thalidomide (25 and 50 mg/kg, i.p) 1 h before or concurrently with morphine significantly restored the analgesic effect of morphine in diabetic rats. CONCLUSION It may be concluded that thalidomide has a beneficial effect in neuropathic pain by decreasing cytokines (TNF-α) and nitric oxide level and may provide a novel promising therapeutic approach for managing painful diabetic neuropathy.
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Phenotypic changes in diabetic neuropathy induced by a high-fat diet in diabetic C57BL/6 mice. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:848307. [PMID: 22144990 PMCID: PMC3226416 DOI: 10.1155/2011/848307] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 08/03/2011] [Accepted: 08/25/2011] [Indexed: 01/05/2023]
Abstract
Emerging evidence suggests that dyslipidemia is an independent risk factor for diabetic neuropathy (DN) (reviewed by Vincent et al. 2009). To experimentally determine how dyslipidemia alters DN, we quantified neuropathic symptoms in diabetic mice fed a high-fat diet. Streptozotocin-induced diabetic C57BL/6 mice fed a high-fat diet developed dyslipidemia and a painful neuropathy (mechanical allodynia) instead of the insensate neuropathy (mechanical insensitivity) that normally develops in this strain. Nondiabetic mice fed a high-fat diet also developed dyslipidemia and mechanical allodynia. Thermal sensitivity was significantly reduced in diabetic compared to nondiabetic mice, but was not worsened by the high-fat diet. Moreover, diabetic mice fed a high-fat diet had significantly slower sensory and motor nerve conduction velocities compared to nondiabetic mice. Overall, dyslipidemia resulting from a high-fat diet may modify DN phenotypes and/or increase risk for developing DN. These results provide new insight as to how dyslipidemia may alter the development and phenotype of diabetic neuropathy.
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Deshpande DD, Janero DR, Amiji MM. Therapeutic strategies for endothelial dysfunction. Expert Opin Biol Ther 2011; 11:1637-54. [DOI: 10.1517/14712598.2011.625007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Effects of a potent peroxynitrite decomposition catalyst in murine models of endotoxemia and sepsis. Shock 2011; 35:560-6. [PMID: 21263378 DOI: 10.1097/shk.0b013e31820fe5d5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Excessive free-radical production due to various bacterial components released during bacterial infection has been linked to cell death and tissue injury. Peroxynitrite is a highly reactive oxidant produced by the combination of nitric oxide (NO) and superoxide anion, which has been implicated in cell death and tissue injury in various forms of critical illness. Pharmacological decomposition of peroxynitrite may represent a potential therapeutic approach in diseases associated with the overproduction of NO and superoxide. In the present study, we tested the effect of a potent peroxynitrite decomposition catalyst in murine models of endotoxemia and sepsis. Mice were injected i.p. with LPS 40 mg/kg with or without FP15 [Fe(III) tetrakis-2-(N-triethylene glycol monomethyl ether)pyridyl porphyrin] (0.1, 0.3, 1, 3, or 10 mg/kg per hour). Mice were killed 12 h later, followed by the harvesting of samples from the lung, liver, and gut for malondialdehyde and myeloperoxidase measurements. In other subsets of animals, blood samples were obtained by cardiac puncture at 1.5, 4, and 8 h after LPS administration for cytokine (TNF-α, IL-1β, and IL-10), nitrite/nitrate, alanine aminotransferase, and blood urea nitrogen measurements. Endotoxemic animals showed an increase in survival from 25% to 80% at the FP15 doses of 0.3 and 1 mg/kg per hour. The same dose of FP15 had no effect on plasma levels of nitrite/nitrate. There was a reduction in liver and lung malondialdehyde in the endotoxemic animals pretreated with FP15, as well as in hepatic myeloperoxidase and biochemical markers of liver and kidney damage (alanine aminotransferase and blood urea nitrogen). In a bacterial model of sepsis induced by cecal ligation and puncture, FP15 treatment (0.3 mg/kg per day) significantly protected against mortality. The current data support the view that peroxynitrite is a critical factor mediating liver, gut, and lung injury in endotoxemia and septic shock: its pharmacological neutralization may be of therapeutic benefit.
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Kumar A, Negi G, Sharma SS. JSH-23 targets nuclear factor-kappa B and reverses various deficits in experimental diabetic neuropathy: effect on neuroinflammation and antioxidant defence. Diabetes Obes Metab 2011; 13:750-8. [PMID: 21447040 DOI: 10.1111/j.1463-1326.2011.01402.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
AIM Nuclear factor-kappa B (NF-κB) being reported to play an important role in the pathogenesis of diabetic neuropathy is believed to be a central mechanism involved in the genesis and promulgation of inflammatory insult. Here we have targeted the nuclear translocation of NF-κB using JSH-23 to elucidate its role in diabetic neuropathy. METHODS JSH-23 (1 and 3 mg/kg) was administered for 2 weeks in diabetic rats, after 6 weeks of diabetes induction using streptozotocin (55 mg/kg) as diabetogenic agent. Functional (motor nerve conduction velocity and blood flow), behavioural (mechanical hyperalgesia), biochemical [malondialdehyde, glutathione, tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels] and NF-κB translocation studies (western blot technique) were then undertaken. RESULTS JSH-23 treatment significantly reversed the nerve conduction and nerve blood flow deficits seen in diabetic animals. Reduction in mechanical pain threshold was also partially corrected by the treatment. Protein expression studies showed that nuclear translocation of p65/p50 subunit was inhibited by JSH-23 treatment in the sciatic nerve. The treatment also lowered the elevated IL-6, TNF-α, cyclo-oxygenase (COX-2) and inducible nitric oxide synthase (iNOS) levels/expression, indicating reduction in the inflammatory damage of the sciatic nerve. Apart from these effects, JSH-23 also increased Nrf2 and hemeoxygenase-1 (HO-1) levels which could imply its potential in increasing the strength of antioxidant defence. CONCLUSION We observed that NF-κB inhibition partially reversed functional, behavioural and biochemical deficits with JSH-23 treatment. This study substantiates the role of NF-κB activation in the aetiology of diabetic neuropathy and protection afforded by inhibition of NF-κB by JSH-23, which can be attributed to its effect on neuroinflammation and oxidative stress.
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Affiliation(s)
- A Kumar
- Molecular Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Mohali, Punjab, India
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Abstract
It has long been recognized that cardiac autonomic neuropathy increases morbidity and mortality in diabetes and may have greater predictive power than traditional risk factors for cardiovascular events. Significant morbidity and mortality can now be attributable to autonomic imbalance between the sympathetic and parasympathetic nervous system regulation of cardiovascular function. New and emerging syndromes include orthostatic tachycardia, orthostatic bradycardia and an inability to use heart rate as a guide to exercise intensity because of the resting tachycardia. Recent studies have shown that autonomic imbalance may be a predictor of risk of sudden death with intensification of glycaemic control. This review examines an association of autonomic dysregulation and the role of inflammatory cytokines and adipocytokines that promote cardiovascular risk. In addition, conditions of autonomic imbalance associated with cardiovascular risk are discussed. Potential treatment for restoration of autonomic balance is outlined.
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Affiliation(s)
- A I Vinik
- Eastern Virginia Medical School, Strelitz Diabetes Research Center and Neuroendocrine Unit, 855 W Brambleton Avenue, Norfolk, VA 23510, USA.
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Lupachyk S, Shevalye H, Maksimchyk Y, Drel VR, Obrosova IG. PARP inhibition alleviates diabetes-induced systemic oxidative stress and neural tissue 4-hydroxynonenal adduct accumulation: correlation with peripheral nerve function. Free Radic Biol Med 2011; 50:1400-9. [PMID: 21300148 PMCID: PMC3081984 DOI: 10.1016/j.freeradbiomed.2011.01.037] [Citation(s) in RCA: 249] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 01/14/2011] [Accepted: 01/31/2011] [Indexed: 10/18/2022]
Abstract
This study evaluated the role of poly(ADP-ribose) polymerase (PARP) in systemic oxidative stress and 4-hydoxynonenal adduct accumulation in diabetic peripheral neuropathy. Control and streptozotocin-diabetic rats were maintained with or without treatment with the PARP inhibitor, 1,5-isoquinolinediol, 3 mg kg(-1) day(-1), for 10 weeks after an initial 2 weeks. Treatment efficacy was evaluated by poly(ADP-ribosyl)ated protein content in peripheral nerve and spinal cord (Western blot analysis) and dorsal root ganglion neurons and nonneuronal cells (fluorescence immunohistochemistry), as well as by indices of peripheral nerve function. Diabetic rats displayed increased urinary isoprostane and 8-hydroxy-2'-deoxyguanosine excretion (ELISA) and 4-hydroxynonenal adduct accumulation in endothelial and Schwann cells of the peripheral nerve, neurons, astrocytes, and oligodendrocytes of the spinal cord and neurons and glial cells of the dorsal root ganglia (double-label fluorescence immunohistochemistry), as well as motor and sensory nerve conduction velocity deficits, thermal hypoalgesia, and tactile allodynia. PARP inhibition counteracted diabetes-induced systemic oxidative stress and 4-hydroxynonenal adduct accumulation in peripheral nerve and spinal cord (Western blot analysis) and dorsal root ganglion neurons (perikarya, fluorescence immunohistochemistry), which correlated with improvement of large and small nerve fiber function. The findings reveal the important role of PARP activation in systemic oxidative stress and 4-hydroxynonenal adduct accumulation in diabetic peripheral neuropathy.
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Affiliation(s)
- Sergey Lupachyk
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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Stadler K. Peroxynitrite-driven mechanisms in diabetes and insulin resistance - the latest advances. Curr Med Chem 2011; 18:280-90. [PMID: 21110800 DOI: 10.2174/092986711794088317] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 11/20/2010] [Indexed: 02/07/2023]
Abstract
Since its discovery, peroxynitrite has been known as a potent oxidant in biological systems, and a rapidly growing body of literature has characterized its biochemistry and role in the pathophysiology of various conditions. Either directly or by inducing free radical pathways, peroxynitrite damages vital biomolecules such as DNA, proteins including enzymes with important functions, and lipids. It also initiates diverse reactions leading eventually to disrupted cell signaling, cell death, and apoptosis. The potential role and contribution of this deleterious species has been the subject of investigation in several important diseases, including but not limited to, cancer, neurodegeneration, stroke, inflammatory conditions, cardiovascular problems, and diabetes mellitus. Diabetes, obesity, insulin resistance, and diabetes-related complications represent a major health problem at epidemic levels. Therefore, tremendous efforts have been put into investigation of the molecular basics of peroxynitrite-related mechanisms in diabetes. Studies constantly seek new therapeutical approaches in order to eliminate or decrease the level of peroxynitrite, or to interfere with its downstream mechanisms. This review is intended to emphasize the latest findings about peroxynitrite and diabetes, and, in addition, to discuss recent and novel advances that are likely to contribute to a better understanding of peroxynitrite-mediated damage in this disease.
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Affiliation(s)
- K Stadler
- Oxidative Stress and Disease Laboratory, Pennington Biomedical Research Center, LSU System, 6400 Perkins Rd, Baton Rouge, LA 70808, USA.
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Stavniichuk R, Drel VR, Shevalye H, Maksimchyk Y, Kuchmerovska TM, Nadler JL, Obrosova IG. Baicalein alleviates diabetic peripheral neuropathy through inhibition of oxidative-nitrosative stress and p38 MAPK activation. Exp Neurol 2011; 230:106-13. [PMID: 21515260 DOI: 10.1016/j.expneurol.2011.04.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 03/29/2011] [Accepted: 04/07/2011] [Indexed: 01/12/2023]
Abstract
With the consideration of the multifactorial etiology of diabetic peripheral neuropathy, an ideal drug or drug combination should target at least several key pathogenetic mechanisms. The flavonoid baicalein (5,6,7-trihydroxyflavone) has been reported to counteract sorbitol accumulation, activation of 12/15-lipoxygenase, oxidative-nitrosative stress, inflammation, and impaired signaling in models of chronic disease. This study evaluated baicalein on diabetic peripheral neuropathy. Control and streptozotocin-diabetic C57Bl6/J mice were maintained with or without baicalein treatment (30 mg kg(-1) d(-1), i.p., for 4 weeks after 12 weeks without treatment). Neuropathy was evaluated by sciatic motor and hind-limb digital sensory nerve conduction velocities, thermal algesia (Hargreaves test), tactile response threshold (flexible von Frey filament test), and intraepidermal nerve fiber density (fluorescent immunohistochemistry with confocal microscopy). Sciatic nerve and spinal cord 12/15-lipoxygenase and total and phosphorylated p38 mitogen-activated protein kinase expression and nitrated protein levels were evaluated by Western blot analysis, 12(S)hydroxyeicosatetraenoic acid concentration (a measure of 12/15-lipoxygenase activity) by ELISA, and glucose and sorbitol pathway intermediate concentrations by enzymatic spectrofluorometric assays. Baicalein did not affect diabetic hyperglycemia, and alleviated nerve conduction deficit and small sensory nerve fiber dysfunction, but not intraepidermal nerve fiber loss. It counteracted diabetes-associated p38 mitogen-activated protein kinase phosphorylation, oxidative-nitrosative stress, and 12/15-lipoxygenase overexpression and activation, but not glucose or sorbitol pathway intermediate accumulation. In conclusion, baicalein targets several mechanisms implicated in diabetic peripheral neuropathy. The findings provide rationale for studying hydroxyflavones with an improved pharmacological profile as potential treatments for diabetic neuropathy and other diabetic complications.
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Affiliation(s)
- Roman Stavniichuk
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
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Watcho P, Stavniichuk R, Tane P, Shevalye H, Maksimchyk Y, Pacher P, Obrosova IG. Evaluation of PMI-5011, an ethanolic extract of Artemisia dracunculus L., on peripheral neuropathy in streptozotocin-diabetic mice. Int J Mol Med 2011; 27:299-307. [PMID: 21225225 DOI: 10.3892/ijmm.2011.597] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 12/13/2010] [Indexed: 11/05/2022] Open
Abstract
We previously reported that PMI-5011, an ethanolic extract of Artemisia dracunculus L., alleviates peripheral neuropathy in high fat diet-fed mice, a model of prediabetes and obesity developing oxidative stress and pro-inflammatory changes in the peripheral nervous system. This study evaluated PMI-5011 on established functional, structural, and biochemical changes associated with Type I diabetic peripheral neuropathy. C57Bl6/J mice with streptozotocin-induced diabetes of a 12-week duration, developed motor and sensory nerve conduction velocity deficits, thermal and mechanical hypoalgesia, tactile allodynia, and intra-epidermal nerve fiber loss. PMI-5011 (500 mg/kg/day for 7 weeks) alleviated diabetes-induced nerve conduction slowing, small sensory nerve fiber dysfunction, and increased intra-epidermal nerve fiber density. PMI-5011 blunted sciatic nerve and spinal cord 12/15-lipoxygenase activation and oxidative-nitrosative stress, without ameliorating hyperglycemia or reducing sciatic nerve sorbitol pathway intermediate accumulation. In conclusion, PMI-5011, a safe and non-toxic botanical extract, may find use in the treatment of diabetic peripheral neuropathy.
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Affiliation(s)
- Pierre Watcho
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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Dobretsov M, Backonja MM, Romanovsky D, Stimers JR. Animal Models of Diabetic Neuropathic Pain. ANIMAL MODELS OF PAIN 2011. [DOI: 10.1007/978-1-60761-880-5_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Protective effects of polyphenolics in red wine on diabetes associated oxidative/nitrative stress in streptozotocin-diabetic rats. Cell Biol Int 2010; 34:1147-53. [DOI: 10.1042/cbi20100201] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Stavniichuk R, Drel VR, Shevalye H, Vareniuk I, Stevens MJ, Nadler JL, Obrosova IG. Role of 12/15-lipoxygenase in nitrosative stress and peripheral prediabetic and diabetic neuropathies. Free Radic Biol Med 2010; 49:1036-45. [PMID: 20599608 PMCID: PMC3056543 DOI: 10.1016/j.freeradbiomed.2010.06.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/08/2010] [Accepted: 06/14/2010] [Indexed: 01/15/2023]
Abstract
This study evaluated the role of 12/15-lipoxygenase, which converts arachidonic acid to 12(S)- and 15(S)-hydroxyeicosatetraenoic acids, in nitrosative stress in the peripheral nervous system and peripheral prediabetic and diabetic neuropathies. The experiments were performed in C57BL6/J mice made diabetic with streptozotocin or fed a high-fat diet and in human Schwann cells cultured in 5.5 or 30 mM glucose. 12/15-Lipoxygenase overexpression and activation were present in sciatic nerve and spinal cord of diabetic and high-fat diet-fed mice, as well as in human Schwann cells cultured in high concentrations of D-, but not L-glucose. 12/15-Lipoxygenase inhibition by cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate (8 mg kg(-1) day(-1) sc, for 4 weeks after 12 weeks without treatment) alleviated the accumulation of nitrated proteins in the sciatic nerve and spinal cord, and large and small nerve fiber dysfunction, but not intraepidermal nerve fiber loss. 12/15-Lipoxygenase gene deficiency alleviated nitrosative stress and nerve conduction deficit, but not small sensory fiber neuropathy, in high-fat diet-fed mice. In conclusion, 12/15-lipoxygenase is implicated in nitrosative stress and peripheral neuropathy in mouse models of type 1 and early type 2 diabetes. Its presence in human Schwann cells and upregulation by high glucose suggest a potential involvement in human disease.
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Affiliation(s)
- Roman Stavniichuk
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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Li Y, Qi J, Liu K, Li B, Wang H, Jia J. Peroxynitrite-induced nitration of cyclooxygenase-2 and inducible nitric oxide synthase promotes their binding in diabetic angiopathy. Mol Med 2010; 16:335-42. [PMID: 20607198 DOI: 10.2119/molmed.2010.00034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 06/29/2010] [Indexed: 11/06/2022] Open
Abstract
Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) play crucial roles in diabetic angiopathy. In vivo, however, the following facts remain unknown: whether COX-2 and iNOS bind, how peroxynitrite-induced nitration of COX-2 and iNOS affects their binding if they do bind and what effects of this mechanism contribute to diabetic angiopathy. This study focused on the issues above. Diabetes was induced in Wistar male rats by intraperitoneal injection of streptozotocin. As a specific scavenger of peroxynitrite, urate was used. After 13 wks of diabetes, the morphological and biochemical changes of the rats showed obvious diabetic angiopathy. There exists in vivo colocalization and binding of COX-2 and iNOS in diabetic angiopathy. The nitration level of total and co-immunoprecipitated COX-2 and iNOS increased significantly, and, simultaneously, their binding and activity increased in the diabetes group. In the diabetes + urate group, the nitration level of COX-2 and iNOS decreased and their binding reduced, consistent with their decreased activity and the attenuated pathological changes in the rat aorta and glomerulus. The results provide in vivo evidence that COX-2 and iNOS can bind in diabetic angiopathy and that peroxynitrite-induced nitration of COX-2 and iNOS promotes their binding, contributing to diabetic angiopathy.
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Affiliation(s)
- Yanning Li
- Department of Molecular Biology, Hebei Key Lab of Laboratory Animal. Hebei Medical University, 361 East Zhongshan Road, Shijiazhuang, PR China
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Taliyan R, Singh M, Sharma P. Beneficial Effect of Cyclosporine in Experimental Diabetes Induced Neuropathic Pain in Rats. INT J PHARMACOL 2010. [DOI: 10.3923/ijp.2010.393.399] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Drel VR, Lupachyk S, Shevalye H, Vareniuk I, Xu W, Zhang J, Delamere NA, Shahidullah M, Slusher B, Obrosova IG. New therapeutic and biomarker discovery for peripheral diabetic neuropathy: PARP inhibitor, nitrotyrosine, and tumor necrosis factor-{alpha}. Endocrinology 2010; 151:2547-55. [PMID: 20357221 PMCID: PMC2875829 DOI: 10.1210/en.2009-1342] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This study evaluated poly(ADP-ribose) polymerase (PARP) inhibition as a new therapeutic approach for peripheral diabetic neuropathy using clinically relevant animal model and endpoints, and nitrotyrosine (NT), TNF-alpha, and nitrite/nitrate as potential biomarkers of the disease. Control and streptozotocin-diabetic rats were maintained with or without treatment with orally active PARP inhibitor 10-(4-methyl-piperazin-1-ylmethyl)-2H-7-oxa-1,2-diaza-benzo[de]anthracen-3-one (GPI-15,427), 30 mg kg(-1) d(-1), for 10 wk after first 2 wk without treatment. Therapeutic efficacy was evaluated by poly(ADP-ribosyl)ated protein expression (Western blot analysis), motor and sensory nerve conduction velocities, and tibial nerve morphometry. Sciatic nerve and spinal cord NT, TNF-alpha, and nitrite/nitrate concentrations were measured by ELISA. NT localization in peripheral nervous system was evaluated by double-label fluorescent immunohistochemistry. A PARP inhibitor treatment counteracted diabetes-induced motor and sensory nerve conduction slowing, axonal atrophy of large myelinated fibers, and increase in sciatic nerve and spinal cord NT and TNF-alpha concentrations. Sciatic nerve NT and TNF-alpha concentrations inversely correlated with motor and sensory nerve conduction velocities and myelin thickness, whereas nitrite/nitrate concentrations were indistinguishable between control and diabetic groups. NT accumulation was identified in endothelial and Schwann cells of the peripheral nerve, neurons, astrocytes, and oligodendrocytes of the spinal cord, and neurons and glial cells of the dorsal root ganglia. The findings identify PARP as a compelling drug target for prevention and treatment of both functional and structural manifestations of peripheral diabetic neuropathy and provide rationale for detailed evaluation of NT and TNF-alpha as potential biomarkers of its presence, severity, and progression.
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Affiliation(s)
- Viktor R Drel
- Pennington Biomedical Research Center, Louisiana State University System, 6400 Perkins Road, Baton Rouge, Louisiana 70808, USA
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70
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Treatment strategies for chemotherapy-induced peripheral neuropathy: potential role of exercise. Oncol Rev 2010. [DOI: 10.1007/s12156-010-0044-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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71
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High-fat diet-induced neuropathy of prediabetes and obesity: effect of PMI-5011, an ethanolic extract of Artemisia dracunculus L. Mediators Inflamm 2010; 2010:268547. [PMID: 20396384 PMCID: PMC2852597 DOI: 10.1155/2010/268547] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 12/16/2022] Open
Abstract
Artemisia species are a rich source of herbal remedies with antioxidant and anti-inflammatory properties. We evaluated PMI-5011, an ethanolic extract of Artemisia dracunculus L., on neuropathy in high-sfat diet-fed mice, a model of prediabetes and obesity developing oxidative stress and proinflammatory changes in peripheral nervous system. C57Bl6/J mice fed high-fat diet for 16 weeks developed obesity, moderate nonfasting hyperglycemia, nerve conduction deficit, thermal and mechanical hypoalgesia, and tactile allodynia. They displayed 12/15-lipoxygenase overexpression, 12(S)-hydroxyeicosatetraenoic acid accumulation, and nitrosative stress in peripheral nerve and spinal cord. PMI-5011 (500 mgkg−1d−1, 7 weeks) normalized glycemia, alleviated nerve conduction slowing and sensory neuropathy, and reduced 12/15-lipoxygenase upregulation and nitrated protein expression in peripheral nervous system. PMI-5011, a safe and nontoxic botanical extract, may find use in treatment of neuropathic changes at the earliest stage of disease.
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72
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Zhang L, Yu C, Vasquez FE, Galeva N, Onyango I, Swerdlow RH, Dobrowsky RT. Hyperglycemia alters the schwann cell mitochondrial proteome and decreases coupled respiration in the absence of superoxide production. J Proteome Res 2010; 9:458-71. [PMID: 19905032 DOI: 10.1021/pr900818g] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hyperglycemia-induced mitochondrial dysfunction contributes to sensory neuron pathology in diabetic neuropathy. Although Schwann cells (SCs) also undergo substantial degeneration in diabetic neuropathy, the effect of hyperglycemia on the SC mitochondrial proteome and mitochondrial function has not been examined. Stable isotope labeling with amino acids in cell culture (SILAC) was used to quantify the temporal effect of hyperglycemia on the mitochondrial proteome of primary SCs isolated from neonatal rats. Of 317 mitochondrial proteins identified, about 78% were quantified and detected at multiple time points. Pathway analysis indicated that proteins associated with mitochondrial dysfunction, oxidative phosphorylation, the TCA cycle, and detoxification were significantly increased in expression and over-represented. Assessing mitochondrial respiration in intact SCs indicated that hyperglycemia increased the overall rate of oxygen consumption but decreased the efficiency of coupled respiration. Although a glucose-dependent increase in superoxide production occurs in embryonic sensory neurons, hyperglycemia did not induce a substantial change in superoxide levels in SCs. This correlated with a 1.9-fold increase in Mn superoxide dismutase expression, which was confirmed by immunoblot and enzymatic activity assays. These data support that hyperglycemia alters mitochondrial respiration and can cause remodeling of the SC mitochondrial proteome independent of significant contributions from glucose-induced superoxide production.
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Affiliation(s)
- Liang Zhang
- Department of Pharmacology and Toxicology and Analytic Proteomics Laboratory, University of Kansas, Lawrence, Kansas 66045, USA
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73
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Abstract
Diabetes mellitus is associated with a 5-fold higher prevalence of cataracts, which remains a major cause of blindness in the world. Typical diabetic cataracts contain cortical and/or posterior subcapsular opacities. Adult onset diabetic cataracts also often contain nuclear opacities. Mechanisms of diabetic cataractogenesis have been studied in less detail than those of other diabetic complications. Both animal and human studies support important contribution of increased aldose reductase activity. Surgical extraction is the only cure of diabetic cataract today. An improved understanding of pathogenetic mechanisms, together with finding effective therapeutic agents, remain highest priority for diabetic cataract-related research and pharmaceutical development.
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Affiliation(s)
- Irina G Obrosova
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
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74
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Cold exposure exacerbates the development of diabetic polyneuropathy in the rat. EXPERIMENTAL DIABETES RESEARCH 2010; 2009:827943. [PMID: 20130819 PMCID: PMC2814234 DOI: 10.1155/2009/827943] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 08/24/2009] [Accepted: 10/11/2009] [Indexed: 01/09/2023]
Abstract
Diabetic polyneuropathy (DPN) and cold-induced nerve injury share several pathogenic mechanisms. This study explores whether cold exposure contributes to the development of DPN. Streptozotocin-induced diabetic rats and controls were exposed to a room temperature (23°C) or cold environment (10°C). H-reflex, tail and sciatic motor, and sensory nerve conduction studies were performed. Analyses of sural nerve, intraepidermal nerve fibers, and skin and nerve nitrotyrosine ELISAs were performed. Diabetic animals exposed to a cold environment had an increased H-reflex four weeks earlier than diabetic room temperature animals (P = .03). Cold-exposed diabetic animals also had greater reduction in motor conduction velocities at 20 weeks (P = .017), decreased skin nerve fiber density (P = .037), and increased skin nitrotyrosine levels (P = .047). Cold exposure appears to hasten the development of DPN in the rat STZ model of diabetes. These findings support that further study into the relationship between ambient temperature and DPN is warranted.
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75
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Negi G, Kumar A, Sharma SS. Concurrent targeting of nitrosative stress-PARP pathway corrects functional, behavioral and biochemical deficits in experimental diabetic neuropathy. Biochem Biophys Res Commun 2009; 391:102-6. [PMID: 19900402 DOI: 10.1016/j.bbrc.2009.11.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 11/04/2009] [Indexed: 12/21/2022]
Abstract
Peroxynitrite mediated nitrosative stress, an indisputable initiator of DNA damage and overactivation of poly(ADP-ribose) polymerase (PARP), a nuclear enzyme activated after sensing DNA damage, are two crucial pathogenetic mechanisms in diabetic neuropathy. The intent of the present study was to investigate the effect of combination of a peroxynitrite decomposition catalyst (PDC), FeTMPyP and a PARP inhibitor, 4-ANI against diabetic peripheral neuropathy. The end points of evaluation of the study included motor nerve conduction velocity (MNCV) and nerve blood flow (NBF) for evaluating nerve functions; thermal hyperalgesia and mechanical allodynia for assessing nociceptive alterations, malondialdehyde and peroxynitrite levels to detect oxidative stress-nitrosative stress; NAD concentration in sciatic nerve to assess overactivation of PARP. Additionally immunohistochemical studies for nitrotyrosine and Poly(ADP-ribose) (PAR) was also performed. Treatment with the combination of FeTMPyP and 4-ANI led to significant improvement in nerve functions and pain parameters and also attenuated the oxidative-nitrosative stress markers. Further, the combination also reduced the overactivation of PARP as evident from increased NAD levels and decreased PAR immunopositivity in sciatic nerve microsections. Thus, it can be concluded that treatment with the combination of a PDC and PARP inhibitor attenuates alteration in peripheral nerves in diabetic neuropathy (DN).
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Affiliation(s)
- Geeta Negi
- Molecular Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector-67, SAS Nagar, Punjab 160062, India
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76
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McGuire JF, Rouen S, Siegfreid E, Wright DE, Dobrowsky RT. Caveolin-1 and altered neuregulin signaling contribute to the pathophysiological progression of diabetic peripheral neuropathy. Diabetes 2009; 58:2677-86. [PMID: 19675140 PMCID: PMC2768162 DOI: 10.2337/db09-0594] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Evaluate if Erb B2 activation and the loss of caveolin-1 (Cav1) contribute to the pathophysiological progression of diabetic peripheral neuropathy (DPN). RESEARCH DESIGN AND METHODS Cav1 knockout and wild-type C57BL/6 mice were rendered diabetic with streptozotocin, and changes in motor nerve conduction velocity (MNCV), mechanical and thermal hypoalgesia, Erb B2 phosphorylation (pErb B2), and epidermal nerve fiber density were assessed. The contribution of Erb B2 to DPN was assessed using the Erb B2 inhibitors PKI 166 and erlotinib and a conditional bitransgenic mouse that expressed a constitutively active form of Erb B2 in myelinated Schwann cells (SCs). RESULTS Diabetic mice exhibited decreased MNCV and mechanical and thermal sensitivity, but the extent of these deficits was more severe in diabetic Cav1 knockout mice. Diabetes increased pErb B2 levels in both genotypes, but the absence of Cav1 correlated with a greater increase in pErb B2. Erb B2 activation contributed to the mechanical hypoalgesia and MNCV deficits in both diabetic genotypes because treatment with erlotinib or PKI 166 improved these indexes of DPN. Similarly, induction of a constitutively active Erb B2 in myelinated SCs was sufficient to decrease MNCV and induce a mechanical hypoalgesia in the absence of diabetes. CONCLUSIONS Increased Erb B2 activity contributes to specific indexes of DPN, and Cav1 may be an endogenous regulator of Erb B2 signaling. Altered Erb B2 signaling is a novel mechanism that contributes to SC dysfunction in diabetes, and inhibiting Erb B2 may ameliorate deficits of tactile sensitivity in DPN.
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Affiliation(s)
- James F. McGuire
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
| | - Shefali Rouen
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
| | - Eric Siegfreid
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
| | - Douglas E. Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas
| | - Rick T. Dobrowsky
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence, Kansas
- Corresponding author: Rick T. Dobrowsky,
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77
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Lucini D, Zuccotti G, Malacarne M, Scaramuzza A, Riboni S, Palombo C, Pagani M. Early progression of the autonomic dysfunction observed in pediatric type 1 diabetes mellitus. Hypertension 2009; 54:987-94. [PMID: 19805636 DOI: 10.1161/hypertensionaha.109.140103] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
To focus on early cardiac and vascular autonomic dysfunction that might complicate type 1 diabetes mellitus in children, we planned an observational, cross-sectional study in a population of 93 young patients, under insulin treatment, subdivided in 2 age subgroups (children: 11.5+/-0.4 years; adolescents: 19.3+/-0.2 years). Time and frequency domain analysis of RR interval and systolic arterial pressure variability provided quantitative indices of the sympatho-vagal balance regulating the heart period, of the gain of cardiac baroreflex, and of the sympathetic vasomotor control. Sixty-eight children of comparable age served as a reference group. At rest, systolic arterial pressure and the power of its low-frequency component were greater in patients than in controls, particularly in children (14.0+/-2.3 versus 3.1+/-0.3 mm Hg2). Moreover, baroreflex gain was significantly reduced in both subgroups of patients. Standing induced similar changes in the autonomic profiles of controls and patients. A repeat study after 1 year showed a progression in low-frequency oscillations of arterial pressure and a shift toward low frequency in RR variability. Data in young patients with type 1 diabetes mellitus show a significant increase in arterial pressure, a reduced gain of the baroreflex regulation of the heart period, and an increase of the low-frequency component of systolic arterial pressure variability, suggestive of simultaneous impairment of vagal cardiac control and increases of sympathetic vasomotor regulation. A repeat study after 1 year shows a further increase of sympathetic cardiac and vascular modulation, suggesting early progression of the autonomic dysfunction.
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Affiliation(s)
- Daniela Lucini
- Centro Ricerca Terapia Neurovegetativa, University of Milan, Milan, Italy
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78
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Obrosova IG. Diabetic painful and insensate neuropathy: pathogenesis and potential treatments. Neurotherapeutics 2009; 6:638-47. [PMID: 19789069 PMCID: PMC5084286 DOI: 10.1016/j.nurt.2009.07.004] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Accepted: 07/09/2009] [Indexed: 12/31/2022] Open
Abstract
Advanced peripheral diabetic neuropathy (PDN) is associated with elevated vibration and thermal perception thresholds that progress to sensory loss and degeneration of all fiber types in peripheral nerve. A considerable proportion of diabetic patients also describe abnormal sensations such as paresthesias, allodynia, hyperalgesia, and spontaneous pain. One or several manifestations of abnormal sensation and pain are described in all the diabetic rat and mouse models studied so far (i.e., streptozotocin-diabetic rats and mice, type 1 insulinopenic BB/Wor and type 2 hyperinsulinemic diabetic BBZDR/Wor rats, Zucker diabetic fatty rats, and nonobese diabetic, Akita, leptin- and leptin-receptor-deficient, and high-fat diet-fed mice). Such manifestations are 1) thermal hyperalgesia, an equivalent of a clinical phenomenon described in early PDN; 2) thermal hypoalgesia, typically present in advanced PDN; 3) mechanical hyperalgesia, an equivalent of pain on pressure in early PDN; 4) mechanical hypoalgesia, an equivalent to the loss of sensitivity to mechanical noxious stimuli in advanced PDN; 5) tactile allodynia, a painful perception of a light touch; and 5) formalin-induced hyperalgesia. Rats with short-term diabetes develop painful neuropathy, whereas those with longer-term diabetes and diabetic mice typically display manifestations of both painful and insensate neuropathy, or insensate neuropathy only. Animal studies using pharmacological and genetic approaches revealed important roles of increased aldose reductase, protein kinase C, and poly(ADP-ribose) polymerase activities, advanced glycation end-products and their receptors, oxidative-nitrosative stress, growth factor imbalances, and C-peptide deficiency in both painful and insensate neuropathy. This review describes recent achievements in studying the pathogenesis of diabetic neuropathic pain and sensory disorders in diabetic animal models and developing potential pathogenetic treatments.
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Affiliation(s)
- Irina G Obrosova
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808, USA.
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79
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Askwith T, Zeng W, Eggo MC, Stevens MJ. Oxidative stress and dysregulation of the taurine transporter in high-glucose-exposed human Schwann cells: implications for pathogenesis of diabetic neuropathy. Am J Physiol Endocrinol Metab 2009; 297:E620-8. [PMID: 19602579 PMCID: PMC3833996 DOI: 10.1152/ajpendo.00287.2009] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 06/30/2009] [Indexed: 02/07/2023]
Abstract
In human Schwann cells, the role of taurine in regulating glucose-induced changes in antioxidant defense systems has been examined. Treatment with high glucose for 7 days induced reactive oxygen species, increased 4-hydroxynoneal adducts (20 +/- 5%, P < 0.05) and poly(ADP-ribosyl)ated proteins (40 +/- 13%, P < 0.05). Increases in these markers of oxidative stress were reversed by simultaneous incubation in 0.25 mM taurine. Both high glucose and taurine independently increased superoxide dismutase and catalase activity and decreased glutathione levels, but their effects were not additive. Glucose reduced taurine transporter (TauT) mRNA and protein in a dose-dependent manner with maximal decreases of 66 +/- 6 and 63 +/- 12%, respectively (P < 0.05 both). The V(max) for taurine uptake was decreased in 30 mM glucose from 61 +/- 5 to 42 +/- 3 pmol x min(-1) x mg protein(-1) (P < 0.001). Glucose-induced TauT downregulation could be reversed by inhibition of aldose reductase, a pathway that depletes NADPH and increases osmotic stress and protein glycation. TauT protein was increased more than threefold, and the V(max) for taurine uptake doubled (P < 0.05 both) by prooxidants. TauT downregulation was reversed both by treatment with the antioxidant alpha-lipoic acid, which increased TauT mRNA by 60% and V(max) by 50% (P < 0.05 both), and by the aldose reductase inhibitor sorbinil, which increased TauT mRNA 380% and V(max) by 98% (P < 0.01 both). These data highlight the potential therapeutic benefits of taurine supplementation in diabetic complications and provide mechanisms whereby taurine restoration could be achieved in order to prevent or reverse diabetic complications.
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Affiliation(s)
- Trevor Askwith
- Dept. of Clinical and Experimental Medicine, Univ. of Birmingham, Birmingham, B15 2TT UK
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80
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81
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Vareniuk I, Pacher P, Pavlov IA, Drel VR, Obrosova IG. Peripheral neuropathy in mice with neuronal nitric oxide synthase gene deficiency. Int J Mol Med 2009; 23:571-80. [PMID: 19360314 DOI: 10.3892/ijmm_00000166] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Evidence for the important role of the potent oxidant peroxynitrite in peripheral diabetic neuropathy and neuropathic pain is emerging. This study evaluated the contribution of neuronal nitric oxide synthase (nNOS) to diabetes-induced nitrosative stress in peripheral nerve and dorsal root ganglia, and peripheral nerve dysfunction and degeneration. Control and nNOS-/- mice were made diabetic with streptozotocin, and maintained for 6 weeks. Peroxynitrite injury was assessed by nitrotyrosine and poly(ADP-ribose) immunoreactivities. Peripheral diabetic neuropathy was evaluated by measurements of sciatic motor and hind-limb digital sensory nerve conduction velocities, thermal algesia, tactile allodynia, and intraepidermal nerve fiber density. Control nNOS-/- mice displayed normal motor nerve conduction velocity and thermal response latency, whereas sensory nerve conduction velocity was slightly lower compared with non-diabetic wild-type mice, and tactile response threshold and intraepidermal nerve fiber density were reduced by 47 and 38%, respectively. Both diabetic wild-type and nNOS-/- mice displayed enhanced nitrosative stress in peripheral nerve. In contrast to diabetic wild-type mice, diabetic nNOS-/- mice had near normal nitrotyrosine and poly(ADP-ribose) immunofluorescence in dorsal root ganglia. Both diabetic wild-type and nNOS-/- mice developed motor and sensory nerve conduction velocity deficits and thermal hypoalgesia although nNOS gene deficiency slightly reduced severity of the three disorders. Tactile response thresholds were similarly decreased in control and diabetic nNOS-/- mice compared with non-diabetic wild-type mice. Intraepidermal nerve fiber density was lower by 27% in diabetic nNOS-/- mice compared with the corresponding non-diabetic group, and by 20% in diabetic nNOS-/- mice compared with diabetic wild-type mice. In conclusion, nNOS is required for maintaining the normal peripheral nerve function and small sensory nerve fibre innervation. nNOS gene deficiency does not protect from development of nerve conduction deficit, sensory neuropathy and intraepidermal nerve fiber loss.
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Affiliation(s)
- Igor Vareniuk
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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82
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Abstract
The endothelium can evoke relaxations (dilatations) of the underlying vascular smooth muscle, by releasing vasodilator substances. The best characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO). The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDHF-mediated responses). Endothelium-dependent relaxations involve both pertussis toxin-sensitive G(i) (e.g. responses to serotonin and thrombin) and pertussis toxin-insensitive G(q) (e.g. adenosine diphosphate and bradykinin) coupling proteins. The release of NO by the endothelial cell can be up-regulated (e.g. by oestrogens, exercise and dietary factors) and down-regulated (e.g. oxidative stress, smoking and oxidized low-density lipoproteins). It is reduced in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively loose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and causing endothelium-dependent hyperpolarizations), endothelial cells also can evoke contraction (constriction) of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factor (EDCF). Most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells. EDCF-mediated responses are exacerbated when the production of NO is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive patients.
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Affiliation(s)
- P M Vanhoutte
- Department of Pharmacology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
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83
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Martínez MC, Andriantsitohaina R. Reactive nitrogen species: molecular mechanisms and potential significance in health and disease. Antioxid Redox Signal 2009; 11:669-702. [PMID: 19014277 DOI: 10.1089/ars.2007.1993] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Reactive nitrogen species (RNS) are various nitric oxide-derived compounds, including nitroxyl anion, nitrosonium cation, higher oxides of nitrogen, S-nitrosothiols, and dinitrosyl iron complexes. RNS have been recognized as playing a crucial role in the physiologic regulation of many, if not all, living cells, such as smooth muscle cells, cardiomyocytes, platelets, and nervous and juxtaglomerular cells. They possess pleiotropic properties on cellular targets after both posttranslational modifications and interactions with reactive oxygen species. Elevated levels of RNS have been implicated in cell injury and death by inducing nitrosative stress. The aim of this comprehensive review is to address the mechanisms of formation and removal of RNS, highlighting their potential cellular targets: lipids, DNA, and proteins. The specific importance of RNS and their paradoxic effects, depending on their local concentration under physiologic conditions, is underscored. An increasing number of compounds that modulate RNS processing or targets are being identified. Such compounds are now undergoing preclinical and clinical evaluations in the treatment of pathologies associated with RNS-induced cellular damage. Future research should help to elucidate the involvement of RNS in the therapeutic effect of drugs used to treat neurodegenerative, cardiovascular, metabolic, and inflammatory diseases and cancer.
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Affiliation(s)
- M Carmen Martínez
- INSERM, U771, CNRS UMR, 6214, and Université d' Angers, Angers, France
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84
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Szabo C. Role of nitrosative stress in the pathogenesis of diabetic vascular dysfunction. Br J Pharmacol 2009; 156:713-27. [PMID: 19210748 DOI: 10.1111/j.1476-5381.2008.00086.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Here we overview the role of reactive nitrogen species (nitrosative stress) and associated pathways in the pathogenesis of diabetic vascular complications. Increased extracellular glucose concentration, a principal feature of diabetes mellitus, induces a dysregulation of reactive oxygen and nitrogen generating pathways. These processes lead to a loss of the vascular endothelium to produce biologically active nitric oxide (NO), which impairs vascular relaxations. Mitochondria play a crucial role in this process: endothelial cells placed in increase extracellular glucose respond with a marked increase in mitochondrial superoxide formation. Superoxide, when combining with NO generated by the endothelial cells (produced by the endothelial isoform of NO synthase), leads to the formation of peroxynitrite, a cytotoxic oxidant. Reactive oxygen and nitrogen species trigger endothelial cell dysfunction through a multitude of mechanisms including substrate depletion and uncoupling of endothelial isoform of NO synthase. Another pathomechanism involves DNA strand breakage and activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP). PARP-mediated poly(ADP-ribosyl)ation and inhibition of glyceraldehyde-3-phosphate dehydrogenase importantly contributes to the development of diabetic vascular complications: it induces activation of multiple pathways of injury including activation of nuclear factor kappa B, activation of protein kinase C and generation of intracellular advanced glycation end products. Reactive species generation and PARP play key roles in the pathogenesis of 'glucose memory' and in the development of injury in endothelial cells exposed to alternating high/low glucose concentrations.
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Affiliation(s)
- Csaba Szabo
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX 77555-0833, USA.
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85
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Szabo C. Role of nitrosative stress in the pathogenesis of diabetic vascular dysfunction. Br J Pharmacol 2009. [PMID: 19210748 DOI: 10.111/j.1476-5381.2008.00086.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Here we overview the role of reactive nitrogen species (nitrosative stress) and associated pathways in the pathogenesis of diabetic vascular complications. Increased extracellular glucose concentration, a principal feature of diabetes mellitus, induces a dysregulation of reactive oxygen and nitrogen generating pathways. These processes lead to a loss of the vascular endothelium to produce biologically active nitric oxide (NO), which impairs vascular relaxations. Mitochondria play a crucial role in this process: endothelial cells placed in increase extracellular glucose respond with a marked increase in mitochondrial superoxide formation. Superoxide, when combining with NO generated by the endothelial cells (produced by the endothelial isoform of NO synthase), leads to the formation of peroxynitrite, a cytotoxic oxidant. Reactive oxygen and nitrogen species trigger endothelial cell dysfunction through a multitude of mechanisms including substrate depletion and uncoupling of endothelial isoform of NO synthase. Another pathomechanism involves DNA strand breakage and activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP). PARP-mediated poly(ADP-ribosyl)ation and inhibition of glyceraldehyde-3-phosphate dehydrogenase importantly contributes to the development of diabetic vascular complications: it induces activation of multiple pathways of injury including activation of nuclear factor kappa B, activation of protein kinase C and generation of intracellular advanced glycation end products. Reactive species generation and PARP play key roles in the pathogenesis of 'glucose memory' and in the development of injury in endothelial cells exposed to alternating high/low glucose concentrations.
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Affiliation(s)
- Csaba Szabo
- Department of Anesthesiology, The University of Texas Medical Branch, Galveston, TX 77555-0833, USA.
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86
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Abstract
Diabetic neuropathy is the most common complication of diabetes, affecting 50% of diabetic patients. Currently, the only treatment for diabetic neuropathy is glucose control and careful foot care. In this review, we discuss the idea that excess glucose overloads the electron transport chain, leading to the production of superoxides and subsequent mitochondrial and cytosolic oxidative stress. Defects in metabolic and vascular pathways intersect with oxidative stress to produce the onset and progression of nerve injury present in diabetic neuropathy. These pathways include the production of advanced glycation end products, alterations in the sorbitol, hexosamine and protein kinase C pathways and activation of poly-ADP ribose polymerase. New bioinformatics approaches can augment current research and lead to new discoveries to understand the pathogenesis of diabetic neuropathy and to identify more effective molecular therapeutic targets.
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Affiliation(s)
- Claudia Figueroa-Romero
- Department of Neurology, University of Michigan, 5017 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA
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87
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Obrosova IG. Diabetes and the peripheral nerve. Biochim Biophys Acta Mol Basis Dis 2008; 1792:931-40. [PMID: 19061951 DOI: 10.1016/j.bbadis.2008.11.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 11/05/2008] [Accepted: 11/06/2008] [Indexed: 12/11/2022]
Abstract
Diabetes-induced damage to peripheral nerve culminates in development of peripheral diabetic neuropathy (PDN), one of the most devastating complications of diabetes mellitus and a leading cause of foot amputation. The pathogenesis of PDN occurs as a consequence of complex interactions among multiple hyperglycemia-initiated mechanisms, impaired insulin signaling, inflammation, hypertension, and disturbances of fatty acid and lipid metabolism. This review describes experimental new findings in animal and cell culture models as well as clinical data suggesting the importance of 1) previously established hyperglycemia-initiated mechanisms such as increased aldose reductase activity, non-enzymatic glycation/glycooxidation, activation of protein kinase C, 2) oxidative-nitrosative stress and poly(ADP-ribose) polymerase activation; 3) mitogen-activated protein kinase and cyclooxygenase-2 activation, impaired Ca(++) homeostasis and signaling, and several other mechanisms, in PDN.
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Affiliation(s)
- Irina G Obrosova
- Pennington Biomedical Research Center, Louisiana State University, 6400 Perkins Road, Baton Rouge, Louisiana 70808, USA.
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88
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Vareniuk I, Pavlov IA, Obrosova IG. Inducible nitric oxide synthase gene deficiency counteracts multiple manifestations of peripheral neuropathy in a streptozotocin-induced mouse model of diabetes. Diabetologia 2008; 51:2126-33. [PMID: 18802679 PMCID: PMC3044437 DOI: 10.1007/s00125-008-1136-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 07/22/2008] [Indexed: 10/21/2022]
Abstract
AIMS/HYPOTHESIS Evidence for the importance of peroxynitrite, a product of superoxide anion radical reaction with nitric oxide, in peripheral diabetic neuropathy is emerging. The role of specific nitric oxide synthase isoforms in diabetes-associated nitrosative stress and nerve fibre dysfunction and degeneration remains unknown. This study evaluated the contribution of inducible nitric oxide synthase (iNOS) to peroxynitrite injury to peripheral nerve and dorsal root ganglia and development of peripheral diabetic neuropathy. METHODS Control mice and mice with iNos (also known as Nos2) gene deficiency (iNos ( -/- )) were made diabetic with streptozotocin, and maintained for 6 weeks. Peroxynitrite injury was assessed by nitrotyrosine and poly(ADP-ribose) accumulation (immunohistochemistry). Thermal algesia was evaluated by paw withdrawal, tail-flick and hot plate tests, mechanical algesia by the Randall-Selitto test, and tactile allodynia by a von Frey filament test. RESULTS Diabetic wild-type mice displayed peroxynitrite injury in peripheral nerve and dorsal root ganglion neurons. They also developed motor and sensory nerve conduction velocity deficits, thermal and mechanical hypoalgesia, tactile allodynia and approximately 36% loss of intraepidermal nerve fibres. Diabetic iNos ( -/- ) mice did not display nitrotyrosine and poly(ADP-ribose) accumulation in peripheral nerve, but were not protected from nitrosative stress in dorsal root ganglia. Despite this latter circumstance, diabetic iNos ( -/- ) mice preserved normal nerve conduction velocities. Small-fibre sensory neuropathy was also less severe in diabetic iNos ( -/- ) than in wild-type mice. CONCLUSIONS/INTERPRETATION iNOS plays a key role in peroxynitrite injury to peripheral nerve, and functional and structural changes of diabetic neuropathy. Nitrosative stress in axons and Schwann cells, rather than dorsal root ganglion neurons, underlies peripheral nerve dysfunction and degeneration.
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Affiliation(s)
- I Vareniuk
- Pennington Biomedical Research Center, Louisiana State University System, LA 70808, USA
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89
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Edwards JL, Vincent A, Cheng T, Feldman EL. Diabetic neuropathy: mechanisms to management. Pharmacol Ther 2008; 120:1-34. [PMID: 18616962 PMCID: PMC4007052 DOI: 10.1016/j.pharmthera.2008.05.005] [Citation(s) in RCA: 472] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 05/15/2008] [Indexed: 02/07/2023]
Abstract
Neuropathy is the most common and debilitating complication of diabetes and results in pain, decreased motility, and amputation. Diabetic neuropathy encompasses a variety of forms whose impact ranges from discomfort to death. Hyperglycemia induces oxidative stress in diabetic neurons and results in activation of multiple biochemical pathways. These activated pathways are a major source of damage and are potential therapeutic targets in diabetic neuropathy. Though therapies are available to alleviate the symptoms of diabetic neuropathy, few options are available to eliminate the root causes. The immense physical, psychological, and economic cost of diabetic neuropathy underscore the need for causally targeted therapies. This review covers the pathology, epidemiology, biochemical pathways, and prevention of diabetic neuropathy, as well as discusses current symptomatic and causal therapies and novel approaches to identify therapeutic targets.
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Affiliation(s)
- James L. Edwards
- The University of Michigan, Department of Neurology, Ann Arbor, Michigan 48109
| | - Andrea Vincent
- The University of Michigan, Department of Neurology, Ann Arbor, Michigan 48109
| | - Thomas Cheng
- The University of Michigan, Department of Neurology, Ann Arbor, Michigan 48109
| | - Eva L. Feldman
- The University of Michigan, Department of Neurology, Ann Arbor, Michigan 48109
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90
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Julius U, Drel VR, Grässler J, Obrosova IG. Nitrosylated proteins in monocytes as a new marker of oxidative-nitrosative stress in diabetic subjects with macroangiopathy. Exp Clin Endocrinol Diabetes 2008; 117:72-7. [PMID: 18726872 DOI: 10.1055/s-2008-1078710] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Peroxynitrite plays an important role in the pathogenesis of diabetic complications. Nitrosylated protein expression in peripheral blood monocytes reflects intracellular peroxynitrite injury, and thus could be a marker of higher diagnostic and prognostic value than plasma nitrotyrosine level. The purpose of this pilot study was to assess if peripheral blood monocytes of diabetic subjects accumulate nitrosylated proteins, and if nitrosylated protein expression correlates with blood glucose control, variables of lipid profile, C-reactive protein concentration (a marker of inflammation), and differs in patients with and without diabetic macrovascular and microvascular complications. METHODS Nitrosylated protein expression in peripheral blood monocytes (Western blot analysis) was assessed in 31 subjects with diabetes mellitus (29 Type 2, 2 Type 1; 20 males, 11 females; mean age 66 years). The presence of microangiopathy was defined by retinopathy, albumin excretion, and/or neuropathy, and macroangiopathy by carotid plaques, a history of myocardial infarction, and/or stroke. RESULTS Diabetic subjects accumulated significant amounts of nitrosylated proteins in peripheral blood monocytes. Nitrosylated protein expression positively correlated with body weight, blood glucose, HbA (1)C, and plasma C-reactive protein concentrations in the whole cohort as well as in subjects with diabetic macroangiopathy. CONCLUSIONS Monocyte nitrosylated protein expression is a new biomarker of metabolic control and inflammation in diabetic subjects with macroangiopathy. A more detailed assessment of diabetic microvascular complications in a larger group of patients is needed to determine if this variable can be employed as a biomarker of the presence, severity, and progression of diabetic neuropathy, retinopathy, and nephropathy.
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Affiliation(s)
- U Julius
- Medical Clinic III, University Hospital, Dresden, Germany.
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91
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Arora M, Kumar A, Kaundal RK, Sharma SS. Amelioration of neurological and biochemical deficits by peroxynitrite decomposition catalysts in experimental diabetic neuropathy. Eur J Pharmacol 2008; 596:77-83. [PMID: 18768138 DOI: 10.1016/j.ejphar.2008.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 07/31/2008] [Accepted: 08/07/2008] [Indexed: 12/11/2022]
Abstract
Diabetic neuropathy, a major complication of diabetes, affects more than 60% of diabetic patients. Recently, involvement of peroxynitrite has been postulated in diabetic neuropathy. In the present study, we have studied the effects of peroxynitrite decomposition catalysts (PDC's)-5,10,15,20-tetrakis(4-sulfonatophenyl) porphyrinato iron(III) [FeTPPS] and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrinato iron(III) [FeTMPyP]-in experimental diabetic neuropathy. Male Sprague-Dawley rats, with six weeks of untreated diabetes were treated for two weeks with peroxynitrite decomposition catalysts. Diabetic animals showed a significant decrease in motor nerve conduction velocity and nerve blood flow, nociception as evident from decreased tail flick latency (hyperalgesia) and increased paw withdrawal pressure (mechanical allodynia) along with elevation in peroxynitrite and reduction in nerve glutathione levels. Two weeks treatment with PDC's significantly improved all the above stated functional and biochemical deficits. Aftermath of this study advocates the beneficial effects of peroxynitrite decomposition catalysts in experimental diabetic neuropathy.
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Affiliation(s)
- Manish Arora
- Molecular Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, S.A.S. Nagar, Mohali, Punjab, India
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92
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Drel VR, Pacher P, Ali TK, Shin J, Julius U, El-Remessy AB, Obrosova IG. Aldose reductase inhibitor fidarestat counteracts diabetes-associated cataract formation, retinal oxidative-nitrosative stress, glial activation, and apoptosis. Int J Mol Med 2008. [PMID: 18506358 DOI: 10.3892/ijmm.21.6.667] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
This study was aimed at evaluating the potent and specific aldose reductase inhibitor fidarestat, on diabetes-associated cataract formation, and retinal oxidative-nitrosative stress, glial activation, and apoptosis. Control and streptozotocin-diabetic rats were treated with or without fidarestat (16 mg kg(-1)d(-1)) for 10 weeks after an initial 2-week period without treatment. Lens changes were evaluated by indirect ophthalmoscopy and portable slit lamp. Nitrotyrosine, poly(ADP-ribose), and glial fibrillary acidic protein expression were assessed by immunohistochemistry. The rate of apoptosis was quantified in flat-mounted retinas by TUNEL assay with immunoperoxidase staining. To dissect the effects of high glucose exposure in retinal microvascular cells, primary bovine retinal pericytes and endothelial cells were cultured in 5 or 30 mM glucose, with or without fidarestat (10 microM) for 3-14 days. Apoptosis was assessed by TUNEL assay, nitrotyrosine and poly(ADP-ribose) by immunocytochemistry, and Bax and Bcl-2 expression by Western blot analyses. Fidarestat treatment prevented diabetic cataract formation and counteracted retinal nitrosative stress, and poly(ADP-ribose) polymerase activation, as well as glial activation. The number of TUNEL-positive nuclei (mean +/- SEM) was increased approximately 4-fold in diabetic rats vs. controls (207+/-33 vs. 49+/-4, p<0.01), and this increase was partially prevented by fidarestat (106+/-34, p<0.05 vs. untreated diabetic group). The apoptotic cell number increased with the prolongation of exposure of both pericytes and endothelial cells to high glucose levels. Fidarestat counteracted nitrotyrosine and poly(ADP-ribose) accumulation and apoptosis in both cell types. Antiapoptotic effect of fidarestat in high glucose-exposed retinal pericytes was not associated with the inhibition of Bax or increase in Bcl-2 expression. In conclusion, the findings, i) support an important role for aldose reductase in diabetes-associated cataract formation, and retinal oxidative-nitrosative stress, glial activation, and apoptosis, and ii) provide a rationale for the development of aldose reductase inhibitors, and, in particular, fidarestat, for the prevention and treatment of diabetic ocular complications.
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Affiliation(s)
- Viktor R Drel
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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