1
|
Mohammed MA, Gharib DM, Reyad HR, Mohamed AA, Elroby FA, Mahmoud HS. Antioxidant and anti-inflammatory properties of alpha-lipoic acid protect against valproic acid-induced liver injury. Can J Physiol Pharmacol 2021; 99:499-505. [PMID: 33275538 DOI: 10.1139/cjpp-2019-0456] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Valproic acid (VPA) is one of the most used antiepileptic drugs despite of its many adverse effects such as anemia, leucopenia, thrombocytopenia, and liver toxicity. The hepatoprotective effect of alpha-lipoic acid (ALA) was confirmed. The aim of this study was to detect the protective effect of ALA against the adverse effects of VPA. To study this, 30 white albino Wistar male rats were divided into four groups. Group I was the control group; Group II included rats that received ALA (100 mg·kg-1·day-1) orally for 14 days; Group III and Group IV included rats that received VPA (500 mg·kg-1·day-1) for 15 days intraperitoneally, but Group IV rats received ALA (100 mg·kg-1·day-1) orally for 14 days prior to VPA. Blood samples were collected and livers were excised from rats for colorimetric analysis and quantitative real-time PCR. The rats that received VPA showed leucopenia, thrombocytopenia, a significant decrease of superoxide dismutase, glutathione, nuclear factor erythroid 2-related factor 2, and sirtuin 1, besides a significant increase of malondialdehyde and tumor necrosis factor α. Prior treatment with ALA prevented all these results; ALA protected against VPA-induced liver damage and hematological disturbance via antioxidant and anti-inflammatory properties.
Collapse
Affiliation(s)
| | | | - Hoda Ramadan Reyad
- Department of Biochemistry, Faculty of Medicine, Beni-Suef University, Egypt
| | - Alaa Aboud Mohamed
- Department of Biochemistry, Faculty of Medicine, Beni-Suef University, Egypt
| | - Fadwa A Elroby
- Department of Forensic Medicine and Toxicology, Faculty of Medicine, Beni-Suef University, Egypt
| | - Hoda Sayed Mahmoud
- Department of Forensic Medicine and Toxicology, Faculty of Medicine, Beni-Suef University, Egypt
| |
Collapse
|
2
|
Rehman MU, Wali AF, Ahmad A, Shakeel S, Rasool S, Ali R, Rashid SM, Madkhali H, Ganaie MA, Khan R. Neuroprotective Strategies for Neurological Disorders by Natural Products: An update. Curr Neuropharmacol 2019; 17:247-267. [PMID: 30207234 PMCID: PMC6425075 DOI: 10.2174/1570159x16666180911124605] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 08/02/2018] [Accepted: 09/05/2018] [Indexed: 01/30/2023] Open
Abstract
Nature has bestowed mankind with surplus resources (natural products) on land and water. Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. These natural products have been experimentally documented to possess various biological properties such as antioxidant, anti-inflammatory and anti-apoptotic activities. In vitro and in vivo studies have further established the usefulness of natural products in various preclinical models of neurodegenerative disorders. Natural products include phytoconstituents, like polyphenolic antioxidants, found in herbs, fruits, nuts, vegetables and also in marine and freshwater flora. These phytoconstituents may potentially suppress neurodegeneration and improve memory as well as cognitive functions of the brain. Also, they are known to play a pivotal role in the prevention and cure of different neurodegenerative diseases, such as Alzheimer's disease, epilepsy, Parkinson's disease and other neuronal disorders. The large-scale neuro-pharmacological activities of natural products have been documented due to the result of either the inhibition of inflammatory processes, or the up-regulation of various cell survival proteins or a combination of both. Due to the scarcity of human studies on neuroprotective effects of natural products, this review focuses on the various established activities of natural products in in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications using the available knowledge in the literature.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Rehan Khan
- Address correspondence to this author at the Department of Nano-Therapeutics, Institute of Nano Science & Technology, Habitat Centre, Phase X, Mohali-160062, Punjab, India; E-mail:
| |
Collapse
|
3
|
Tekdemir E, Tatlipinar A, Özbeyli D, Tekdemir Ö, Kınal E. The effects of lipoic acid and methylprednisolone on nerve healing in rats with facial paralysis . Acta Otolaryngol 2018; 138:537-541. [PMID: 29310488 DOI: 10.1080/00016489.2017.1420914] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To investigate the effects of lipoic acid and methylprednisolone on nerve healing in rats with traumatic facial paralysis. MATERIALS AND METHODS The rats were randomly divided into four groups, with six rats in the control group and eight each in the remaining three groups. The buccal branch of the facial nerve in all groups except the control group was traumatized by a vascular clamp for 40 minutes. Group 1 was given lipoic acid (LA), Group 2 was given methylprednisolone (MP), and Group 3 was given lipoic acid and methylprednisolone (LA + MP) for one week. Nerve stimulus thresholds were measured before trauma, after trauma and at the end of the one week treatment period. RESULTS When the groups were compared with each other, post-treatment threshold levels of LA + MP were significantly lower than LA. Although post-treatment threshold levels of LA and MP were still higher than the control group, there was no significant difference between LA + MP and control values (p > .05). CONCLUSION Lipoic acid has a positive effect on nerve healing and can enhance the effect of methylprednisolone treatment. It is a good alternative in cases where methylprednisolone cannot be used.
Collapse
Affiliation(s)
- Emrah Tekdemir
- ENT Clinic, Fatih Sultan Mehmet Training and Research Hospital, Kozyatagi, Istanbul, Turkey
| | - Arzu Tatlipinar
- ENT Clinic, Fatih Sultan Mehmet Training and Research Hospital, Kozyatagi, Istanbul, Turkey
| | - Dilek Özbeyli
- Experimental Animal Laboratory, Marmara University School of Medicine, Uskudar, Istanbul, Turkey
| | - Özge Tekdemir
- Internal Medicine Clinic, Haydarpasa Numune Training and Research Hospital, Uskudar, Istanbul, Turkey
| | - Emrah Kınal
- ENT Clinic, Fatih Sultan Mehmet Training and Research Hospital, Kozyatagi, Istanbul, Turkey
| |
Collapse
|
4
|
Saleh TM, Saleh MC, Connell BJ, Kucukkaya I, Abd-El-Aziz AS. A novel synthetic chemical entity (UPEI-800) is neuroprotective in vitro and in an in vivo rat model of oxidative stress. Clin Exp Pharmacol Physiol 2017; 44:993-1000. [PMID: 28504843 DOI: 10.1111/1440-1681.12785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/12/2017] [Accepted: 05/09/2017] [Indexed: 01/05/2023]
Abstract
In this study, we tested a novel synthetic pyrazole-containing compound, 5-amino-1-phenyl-1H-pyrazole-4-carbonitrile (APPC), as an antioxidant in both in vitro and in vivo models of oxidative stress. In addition, the utility of covalently combining APPC with another well-established antioxidant, lipoic acid (LA), was also tested in both models. The in vitro results demonstrated that pretreatment with APPC in a mixed neuronal-glial culture exposed to oxygen-glucose deprivation (OGD) followed by reoxygenation-refeeding, resulted in significant neuroprotection at concentrations between 2.5 to 25 μmol/L. In contrast, LA was not neuroprotective following OGD alone or following reoxygenation-refeeding. However, the synthetic covalent combination of APPC with LA, named "UPEI-800", resulted in significant neuroprotection at concentrations between 0.027 and 2.7 μmol/L (100-fold more potent than APPC alone), an effect shown to be correlated with increased cellular antioxidant capacity. Further, in an in vivo model of ischaemia-reperfusion injury following transient occlusion of the middle cerebral artery (tMCAO), both APPC (0.1 and 1.0 mg/kg) and UPEI-800 (1×10-3 mg/kg) provided significant neuroprotection. Consistent with the in vitro findings, the in vivo results following tMCAO also demonstrated a 100-fold increase in the potency of the covalently linked compound UPEI-800 compared to APPC alone.
Collapse
Affiliation(s)
- Tarek M Saleh
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada.,Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Monique C Saleh
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Barry J Connell
- Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Inan Kucukkaya
- Department of Chemistry, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Alaa S Abd-El-Aziz
- Department of Chemistry, University of Prince Edward Island, Charlottetown, PE, Canada
| |
Collapse
|
5
|
Xu L, Hiller S, Simington S, Nickeleit V, Maeda N, James LR, Yi X. Influence of Different Levels of Lipoic Acid Synthase Gene Expression on Diabetic Nephropathy. PLoS One 2016; 11:e0163208. [PMID: 27706190 PMCID: PMC5051822 DOI: 10.1371/journal.pone.0163208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
Oxidative stress is implicated in the pathogenesis of diabetic nephropathy (DN) but outcomes of many clinical trials are controversial. To define the role of antioxidants in kidney protection during the development of diabetic nephropathy, we have generated a novel genetic antioxidant mouse model with over- or under-expression of lipoic acid synthase gene (Lias). These models have been mated with Ins2Akita/+ mice, a type I diabetic mouse model. We compare the major pathologic changes and oxidative stress status in two new strains of the mice with controls. Our results show that Ins2Akita/+ mice with under-expressed Lias gene, exhibit higher oxidative stress and more severe DN features (albuminuria, glomerular basement membrane thickening and mesangial matrix expansion). In contrast, Ins2Akita/+ mice with highly-expressed Lias gene display lower oxidative stress and less DN pathologic changes. Our study demonstrates that strengthening endogenous antioxidant capacity could be an effective strategy for prevention and treatment of DN.
Collapse
Affiliation(s)
- Longquan Xu
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Sylvia Hiller
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Stephen Simington
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Volker Nickeleit
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Nobuyo Maeda
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Leighton R. James
- Division of Nephrology and Hypertension, Department of Medicine, University of Florida, Jacksonville, Florida, United States of America
- * E-mail: (XY); (LRJ)
| | - Xianwen Yi
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
- * E-mail: (XY); (LRJ)
| |
Collapse
|
6
|
Study of the therapeutic effects of Lactobacillus and α-lipoic acid against dimethylnitrosamine-induced liver fibrosis in rats. J Genet Eng Biotechnol 2014. [DOI: 10.1016/j.jgeb.2014.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
7
|
Adeghate E, Fehér E, Kalász H. Evaluating the Phase II drugs currently under investigation for diabetic neuropathy. Expert Opin Investig Drugs 2014; 24:1-15. [PMID: 25171371 DOI: 10.1517/13543784.2014.954033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Introduction: The worldwide number of patients suffering from diabetes mellitus (DM) is projected to approach 552 million by the year 2030. As diabetic neuropathy (DN) is present in 8% of new diabetic patients at the time of diagnosis and occurs in ∼ 50% of all patients with established DM, the number of patients who will develop painful DN will also increase. The suboptimal efficacies of currently approved drugs have prompted investigators to develop new therapeutic agents for the management of painful DN. Areas covered: In this review, the authors present and elucidate the current status of drugs under investigation for the treatment of painful DN. A short synopsis of currently approved drugs is also given. Literature information and data analysis were retrieved from PubMed, the American Diabetes and Neurological Associations Websites and ClinicalTrials.gov. The keywords used in the search included: DM, DN, painful diabetic neuropathy. Expert opinion: In addition to treating the pain associated with DN, the actual causes of the disease should also be targeted for improved management. It is hoped that drugs which improve vascular blood flow, induce neural regeneration, reduce hyperglycemia, oxidative stress and inflammation can be more effective for the overall treatment of painful DN.
Collapse
Affiliation(s)
- Ernest Adeghate
- United Arab Emirates University, College of Medicine and Health Sciences, Department of Anatomy , P.O Box 17666, Al Ain , UAE +971 3 7672033 ;
| | | | | |
Collapse
|
8
|
Neuroprotective activity of thioctic acid in central nervous system lesions consequent to peripheral nerve injury. BIOMED RESEARCH INTERNATIONAL 2013; 2013:985093. [PMID: 24527432 PMCID: PMC3914604 DOI: 10.1155/2013/985093] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 11/25/2013] [Accepted: 11/25/2013] [Indexed: 11/21/2022]
Abstract
Peripheral neuropathies are heterogeneous disorders presenting often with hyperalgesia and allodynia. This study has assessed if chronic constriction injury (CCI) of sciatic nerve is accompanied by increased oxidative stress and central nervous system (CNS) changes and if these changes are sensitive to treatment with thioctic acid. Thioctic acid is a naturally occurring antioxidant existing in two optical isomers (+)- and (−)-thioctic acid and in the racemic form. It has been proposed for treating disorders associated with increased oxidative stress. Sciatic nerve CCI was made in spontaneously hypertensive rats (SHRs) and in normotensive reference cohorts. Rats were untreated or treated intraperitoneally for 14 days with (+/−)-, (+)-, or (−)-thioctic acid. Oxidative stress, astrogliosis, myelin sheets status, and neuronal injury in motor and sensory cerebrocortical areas were assessed. Increase of oxidative stress markers, astrogliosis, and neuronal damage accompanied by a decreased expression of neurofilament were observed in SHR. This phenomenon was more pronounced after CCI. Thioctic acid countered astrogliosis and neuronal damage, (+)-thioctic acid being more active than (+/−)- or (−)-enantiomers. These findings suggest a neuroprotective activity of thioctic acid on CNS lesions consequent to CCI and that the compound may represent a therapeutic option for entrapment neuropathies.
Collapse
|
9
|
Dudek M, Bilska-Wilkosz A, Knutelska J, Mogilski S, Bednarski M, Zygmunt M, Iciek M, Sapa J, Bugajski D, Filipek B, Włodek L. Are anti-inflammatory properties of lipoic acid associated with the formation of hydrogen sulfide? Pharmacol Rep 2013; 65:1018-24. [DOI: 10.1016/s1734-1140(13)71084-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 02/05/2013] [Indexed: 01/02/2023]
|
10
|
Brain activity of thioctic Acid enantiomers: in vitro and in vivo studies in an animal model of cerebrovascular injury. Int J Mol Sci 2013; 14:4580-95. [PMID: 23443159 PMCID: PMC3634420 DOI: 10.3390/ijms14034580] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 02/19/2013] [Accepted: 02/20/2013] [Indexed: 01/27/2023] Open
Abstract
Oxidative stress is an imbalance between the production of free radicals and antioxidant defense mechanisms, potentially leading to tissue damage. Oxidative stress has a key role in the development of cerebrovascular and/or neurodegenerative diseases. This phenomenon is mainly mediated by an enhanced superoxide production by the vascular endothelium with its consequent dysfunction. Thioctic, also known as alpha-lipoic acid (1,2-dithiolane-3-pentanoic acid), is a naturally occurring antioxidant that neutralizes free radicals in the fatty and watery regions of cells. Both the reduced and oxidized forms of the compound possess antioxidant ability. Thioctic acid has two optical isomers designated as (+)- and (−)-thioctic acid. Naturally occurring thioctic acid is the (+)-thioctic acid form, but the synthetic compound largely used in the market for stability reasons is a mixture of (+)- and (−)-thioctic acid. The present study was designed to compare the antioxidant activity of the two enantiomers versus the racemic form of thioctic acid on hydrogen peroxide-induced apoptosis in a rat pheochromocytoma PC12 cell line. Cell viability was evaluated by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and free oxygen radical species (ROS) production was assessed by flow cytometry. Antioxidant activity of the two enantiomers and the racemic form of thioctic acid was also evaluated in spontaneously hypertensive rats (SHR) used as an in vivo model of increased oxidative stress. A 3-h exposure of PC12 cells to hydrogen peroxide (H2O2) significantly decreased cell viability and increased levels of intracellular ROS production. Pre-treatment with racemic thioctic acid or (+)-enantiomer significantly inhibited H2O2-induced decrease in cell viability from the concentration of 50 μmol/L and 20 μmol/L, respectively. Racemic thioctic acid and (+)-salt decreased levels of intracellular ROS, which were unaffected by (−)-thioctic acid. In the brain of SHR, the occurrence of astrogliosis and neuronal damage, with a decreased expression of neurofilament 200 kDa were observed. Treatment of SHR for 30 days with (+)-thioctic acid reduced the size of astrocytes and increased the neurofilament immunoreaction. The above findings could contribute to clarify the role played by thioctic acid in central nervous system injury related to oxidative stress. The more pronounced effect of (+)-thioctic acid observed in this study may have practical therapeutic implications worthy of being investigated in further preclinical and clinical studies.
Collapse
|
11
|
McIlduff CE, Rutkove SB. Critical appraisal of the use of alpha lipoic acid (thioctic acid) in the treatment of symptomatic diabetic polyneuropathy. Ther Clin Risk Manag 2011; 7:377-85. [PMID: 21941444 PMCID: PMC3176171 DOI: 10.2147/tcrm.s11325] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The most common of the neuropathies associated with diabetes mellitus, diabetic sensorimotor polyneuropathy (DSPN) is a syndrome of diffuse, length-dependent, symmetric nerve dysfunction. The condition is linked with substantial morbidity, frequent healthcare utilization, and compromised quality of life due to related discomfort. Correspondingly, antidepressants, anticonvulsants, and opioids are regularly prescribed with the goal of pain control. However, the agents rarely provide complete pain relief and fail to address progression of the disorder. Whereas strict blood glucose control can slow the onset and worsening of DSPN, near-normoglycemia is not easily attainable. Evidence implicating oxidative processes in the pathogenesis of DSPN offers one potentially important therapeutic avenue. Due to its properties as a potent antioxidant, alpha lipoic acid (ALA) could mitigate the development of DSPN and attenuate resultant symptoms and signs. Approved for treatment of DSPN in Germany, the agent is not more widely used due to uncertainty about its efficacy and reported adverse effects. Here we review the effectiveness and tolerability of ALA in the treatment of symptomatic DSPN. METHODS The MEDLINE, EMBASE, and Cochrane Library databases were searched for English-language literature on the topic. Randomized, blinded studies comparing parenteral and oral ALA with placebo in the treatment of peripheral neuropathy in diabetic adults were selected. Analysis included studies with a level of evidence of at least 2b. RESULTS The current appraisal summarizes data from 1160 participants in the ALADIN, SYDNEY, ORPIL, SYDNEY 2, and ALADIN III trials. In four of the studies, ALA provided significant improvement in manifestations of DSPN. CONCLUSION Treatment with ALA 600 mg iv daily for 3 weeks represents a well-tolerated and effective therapy for DSPN. An oral dose of 600 mg daily administered for up to 5 weeks could offer benefits in symptoms and signs of DSPN without significant side effects.
Collapse
Affiliation(s)
- Courtney E McIlduff
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | |
Collapse
|
12
|
Toklu HZ, Hakan T, Celik H, Biber N, Erzik C, Ogunc AV, Akakin D, Cikler E, Cetinel S, Ersahin M, Sener G. Neuroprotective effects of alpha-lipoic acid in experimental spinal cord injury in rats. J Spinal Cord Med 2010; 33:401-9. [PMID: 21061900 PMCID: PMC2964029 DOI: 10.1080/10790268.2010.11689719] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Oxidative stress is a mediator of secondary injury to the spinal cord following trauma. OBJECTIVE To investigate the putative neuroprotective effect of alpha-lipoic acid (LA), a powerful antioxidant, in a rat model of spinal cord injury (SCI). METHODS Wistar albino rats were divided as control, vehicle-treated SCI, and LA-treated SCI groups. To induce SCI, a standard weight-drop method that induced a moderately severe injury (100 g/cm force) at T10 was used. Injured animals were given either 50 mg/kg LA or saline at 30 minutes postinjury by intraperitoneal injection. At 7 days postinjury, neurologic examination was performed, and rats were decapitated. Spinal cord samples were taken for histologic examination or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, and DNA fragmentation. Formation of reactive oxygen species in spinal cord tissue samples was monitored by using a chemiluminescence (CL) technique. RESULTS SCI caused a significant decrease in spinal cord GSH content, which was accompanied with significant increases in luminol CL and MDA levels, MPO activity, and DNA damage. Furthermore, LA treatment reversed all these biochemical parameters as well as SCI-induced histopathologic alterations. Conversely, impairment of the neurologic function caused by SCI remained unchanged. CONCLUSION The present study suggests that LA reduces SCI-induced oxidative stress and exerts neuroprotection by inhibiting lipid peroxidation, glutathione depletion, and DNA fragmentation.
Collapse
Affiliation(s)
- Hale Z Toklu
- Marmara University School of Pharmacy, Department of Pharmacology, Istanbul, Turkey.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Haenen GRMM, Arts MJTJ, Bast A, Coleman MD. Structure and activity in assessing antioxidant activity in vitro and in vivo A critical appraisal illustrated with the flavonoids. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2006; 21:191-198. [PMID: 21783657 DOI: 10.1016/j.etap.2005.07.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Structure-activity relationships are indispensable to identify the most optimal antioxidants. The advantages of in vitro over in vivo experiments for obtaining these relationships are, that the structure is better defined in vitro, since less metabolism takes place. It is also the case that the concentration, a parameter that is directly linked to activity, is more accurately controlled. Moreover, the reactions that occur in vivo, including feed-back mechanisms, are often too multi-faceted and diverse to be compensated for during the assessment of a single structure-activity relationship. Pitfalls of in vitro antioxidant research include: (i) by definition, antioxidants are not stable and substantial amounts of oxidation products are formed and (ii) during the scavenging of reactive species, reaction products of the antioxidants accumulate. Another problem is that the maintenance of a defined concentration of antioxidants is subject to processes such as oxidation and the formation of reaction products during the actual antioxidant reaction, as well as the compartmentalization of the antioxidant and the reactive species in the in vitro test system. So determinations of in vitro structure-activity relationships are subject to many competing variables and they should always be evaluated critically.
Collapse
Affiliation(s)
- Guido R M M Haenen
- Department of Pharmacology & Toxicology, Universtat Maastricht, Maastricht, The Netherlands
| | | | | | | |
Collapse
|
14
|
Evans JL, Jallal B. Protein tyrosine phosphatases: their role in insulin action and potential as drug targets. Expert Opin Investig Drugs 2005; 8:139-60. [PMID: 15992069 DOI: 10.1517/13543784.8.2.139] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein tyrosine phosphatases (PTPases) are the enzymes responsible for the selective dephosphorylation of tyrosine residues. PTPases function to regulate a wide array of biological responses mediated by growth factors and other stimuli by balancing the cellular level of phosphotyrosine in concert with their counterparts, protein tyrosine kinases. The important roles which PTPases play in regulating intracellular signalling and, ultimately, biological function along with the recent availability of information regarding their structural features has highlighted them as potential targets for pharmacological modulation. This is demonstrated by the increased level of activity directed towards the identification of novel small-molecule PTPase inhibitors. The rationale and potential utility of this drug discovery approach is discussed here, with particular emphasis on its application for the treatment of insulin resistance and Type 2 diabetes.
Collapse
Affiliation(s)
- J L Evans
- Diabetes Program, SUGEN, Inc., 230 East Grand Avenue, San Francisco, CA 94080, USA.
| | | |
Collapse
|
15
|
Hoitsma E, Reulen JPH, de Baets M, Drent M, Spaans F, Faber CG. Small fiber neuropathy: a common and important clinical disorder. J Neurol Sci 2004; 227:119-30. [PMID: 15546602 DOI: 10.1016/j.jns.2004.08.012] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 08/27/2004] [Accepted: 08/30/2004] [Indexed: 11/21/2022]
Abstract
Small fiber neuropathy (SFN) is a neuropathy selectively involving small diameter myelinated and unmyelinated nerve fibers. Interest in this disorder has considerably increased during the past few years. It is often idiopathic and typically presents with peripheral pain and/or symptoms of autonomic dysfunction. Diagnosis is made on the basis of the clinical features, normal nerve conduction studies (NCS) and abnormal specialized tests of small nerve fibers. Among others, these tests include assessment of epidermal nerve fiber density, temperature sensation tests for sensory fibers and sudomotor and cardiovagal testing (QSART) for autonomic fibers. Unless an underlying disease is identified, treatment is usually symptomatic and directed towards alleviation of neuropathic pain.
Collapse
Affiliation(s)
- E Hoitsma
- Department of Clinical Neurophysiology, Maastricht University Hospital, Maastricht, The Netherlands.
| | | | | | | | | | | |
Collapse
|
16
|
Gruzman A, Hidmi A, Katzhendler J, Haj-Yehie A, Sasson S. Synthesis and characterization of new and potent α-lipoic acid derivatives. Bioorg Med Chem 2004; 12:1183-90. [PMID: 14980629 DOI: 10.1016/j.bmc.2003.11.025] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2003] [Accepted: 11/19/2003] [Indexed: 02/02/2023]
Abstract
alpha-Lipoic acid [5-[1,2]-dithiolan-3-yl-pentanoic acid (LA)] is a natural antioxidant and cofactor of several enzymes. It increases the glucose transport activity in skeletal muscles and adipocytes in a non-insulin dependent manner. Therefore, LA is widely used in Type 2 diabetic patients as an oral auxiliary drug. However, large doses of LA (0.8-1.8 gr/day p.o.) are required due to its unfavorable pharmacokinetic parameters. In order to improve these parameters, we synthesized ester and amide LA derivates. Two of these newly synthesized compounds, 5-[1,2]-dithiolan-3-yl-pentanoic acid 3-(5-[1,2]dithiolan-3yl-pentanoylamino)-propyl]-amide (AN-7) and 5-[1,2]-dithiolan-3-yl-pentanoic acid 3-(5-[1,2]-dithiolan-3yl-pentanoyloxy)-propyl ester (AN-8) augmented the rate glucose transport in myotubes in culture in the absence or presence of insulin. Their potency was 12-fold higher than that of the parent compound; their maximal stimulatory effect was 1.5-fold higher than that of LA. When tested in vivo in streptozotocin-diabetic C57/Black mice, AN-7 (10 mg/kg/day for 2 weeks, s.c.) reduced blood glucose level by 39% while a higher dose of LA (50 mg/kg/day for 2 weeks, s.c.) lowered it by 30%. These results indicate that AN-7 is more potent than LA in augmenting glucose transport in skeletal muscles and reducing blood glucose in diabetic animals.
Collapse
Affiliation(s)
- Arie Gruzman
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, PO Box 12272, Jerusalem, Israel
| | | | | | | | | |
Collapse
|
17
|
Affiliation(s)
- Aalt Bast
- Department of Pharmacology and Toxicology, Faculty of Medicine, University Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | | |
Collapse
|
18
|
Kiemer AK, Müller C, Vollmar AM. Inhibition of LPS-induced nitric oxide and TNF-alpha production by alpha-lipoic acid in rat Kupffer cells and in RAW 264.7 murine macrophages. Immunol Cell Biol 2002; 80:550-7. [PMID: 12406389 DOI: 10.1046/j.1440-1711.2002.01124.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The activation of Kupffer cells represents a central mechanism of inflammatory liver injury involving the production of two important inflammatory mediators, nitric oxide and TNF-alpha. The aim of this study was to investigate the effect of the hepatoprotective compound alpha-lipoic acid (thioctic acid) on the production of nitric oxide and TNF-alpha in isolated rat Kupffer cells and RAW 264.7 macrophages. Isolated rat Kupffer cells or RAW 264.7 were either untreated, treated with alpha-lipoic acid (500 micro g/mL), or activated with 1 micro g/mL of lipopolysaccharide in the presence or absence of alpha-lipoic acid (0.2-500 micro g/mL). After 20 h the accumulation of nitrite was measured by the Griess assay. Tumour necrosis factor-alpha secretion was quantified after 4 h by L929 bioassay. Cell viability was determined by mitochondrial reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test, nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) DNA binding activity by gelshift assays. Treatment of Kupffer cells and RAW 264.7 with alpha-lipoic acid alone had no effect on basal nitric oxide production. However, alpha-lipoic acid significantly inhibited lipopolysaccharide-induced nitrite accumulation. alpha-Lipoic acid did not alter basal TNF-alpha secretion in Kupffer cells, whereas it significantly inhibited lipopolysaccharide-induced TNF-alpha production. alpha-Lipoic acid attenuated the activation of nuclear factor-kappaB and AP-1, two transcription factors pivotal in induction of inducible nitric oxide synthase and TNF-alpha. alpha-Lipoic acid significantly inhibits lipopolysaccharide-induced macrophage production of nitric oxide and TNF-alpha via an attenuated activation of NF-kappaB and activator protein-1. The reduced production of nitric oxide and TNF-alpha in Kupffer cells may be involved in the hepatoprotective action conveyed by alpha-lipoic acid.
Collapse
Affiliation(s)
- Alexandra K Kiemer
- Department of Pharmacy, Center of Drug Research, University of Munich, Germany.
| | | | | |
Collapse
|
19
|
Bast A, Haenen GRMM. The toxicity of antioxidants and their metabolites. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2002; 11:251-258. [PMID: 21782609 DOI: 10.1016/s1382-6689(01)00118-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2001] [Revised: 11/02/2001] [Accepted: 11/09/2001] [Indexed: 05/31/2023]
Abstract
Antioxidants are used on a very large scale to try to obtain and preserve optimal health. Nutraceuticals and food supplements frequently contain huge dosages of antioxidants. It is not generally recognised that high intake of antioxidants may also have adverse effects. Three antioxidants i.e. vitamin E, β-carotene and lipoic acid are used to illustrate general considerations on the toxicity of antioxidants. Based on the examples the following recommendations for the evaluation of the toxicity of antioxidants are made: (i) classical safety factors should not be used. (ii) Knowledge on the mechanism of the efficacy and toxicity of antioxidants should be increased. (iii) Bio-kinetic/bio-efficacy modelling might be of help to optimise dosage. (iv) When antioxidant supplementation changes into therapy, a more accurate risk/benefit analyses is warranted.
Collapse
Affiliation(s)
- Aalt Bast
- Department of Pharmacology and Toxicology, Faculty of Medicine, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | | |
Collapse
|
20
|
Evans JL, Heymann CJ, Goldfine ID, Gavin LA. Pharmacokinetics, tolerability, and fructosamine-lowering effect of a novel, controlled-release formulation of alpha-lipoic acid. Endocr Pract 2002; 8:29-35. [PMID: 11951812 DOI: 10.4158/ep.8.1.29] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To determine the pharmacokinetics, safety, and tolerability of a novel, controlled-release oral formulation of alpha-lipoic acid (LA) and to investigate whether sustaining the concentration of LA in plasma would have a beneficial effect on glycemic control in patients with type 2 diabetes. METHODS For the pharmacokinetic study, a single, 600-mg dose of either controlled-release LA (CRLA) or quick-release LA (QRLA) was administered orally to 12 normal human subjects. The plasma profile of LA was determined for 24 hours after administration of the dose,and pharmacokinetic analyses were performed. For the safety and tolerability study, 21 patients with type 2 diabetes were given 900 mg of CRLA daily for 6 weeks, followed by 1,200 mg of CRLA daily for an additional 6 weeks. Active treatment was followed by a 3-week washout period. Throughout the study, patients continued to take their prestudy antidiabetic medications, which included metformin (Glucophage), sulfonylureas (Amaryl, glyburide, and Glucotrol), acarbose (Precose), troglitazone (Rezulin), and insulin (either as monotherapy or in combination). CRLA was evaluated for safety and tolerability as well as for effects on glycemic control. RESULTS The Tmax (time to maximal plasma concentration) of LA administered as CRLA was 1.25 hours and was approximately 2.5-fold longer in comparison with the Tmax for QRLA (Tn,5X = 0.5 hour; P<0.02). No severe side effects or changes in either liver or kidney function or hematologic profiles were noted after the administration of CRLA. In 15 patients, the mean plasma fructosamine concentration was reduced from 313 to 283 micromol/L(P<0.05) after 12 weeks of treatment with CRLA. CONCLUSION CRLA increased the plasma concentration of LA over time in healthy subjects, and CRLA was safe, well tolerated, and effective in reducing plasma fructosamine in patients with type 2 diabetes.
Collapse
Affiliation(s)
- Joseph L Evans
- Northern California Diabetes Institute, Seton Medical Center, Dale City, CA 94015, USA
| | | | | | | |
Collapse
|
21
|
Packer L, Kraemer K, Rimbach G. Molecular aspects of lipoic acid in the prevention of diabetes complications. Nutrition 2001; 17:888-95. [PMID: 11684397 DOI: 10.1016/s0899-9007(01)00658-x] [Citation(s) in RCA: 335] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alpha-lipoic acid (LA) and its reduced form, dihydrolipoic acid, are powerful antioxidants. LA scavenges hydroxyl radicals, hypochlorous acid, peroxynitrite, and singlet oxygen. Dihydrolipoic acid also scavenges superoxide and peroxyl radicals and can regenerate thioredoxin, vitamin C, and glutathione, which in turn can recycle vitamin E. There are several possible sources of oxidative stress in diabetes including glycation reactions, decompartmentalization of transition metals, and a shift in the reduced-oxygen status of the diabetic cells. Diabetics have increased levels of lipid hydroperoxides, DNA adducts, and protein carbonyls. Available data strongly suggest that LA, because of its antioxidant properties, is particularly suited to the prevention and/or treatment of diabetic complications that arise from an overproduction of reactive oxygen and nitrogen species. In addition to its antioxidant properties, LA increases glucose uptake through recruitment of the glucose transporter-4 to plasma membranes, a mechanism that is shared with insulin-stimulated glucose uptake. Further, recent trials have demonstrated that LA improves glucose disposal in patients with type II diabetes. In experimental and clinical studies, LA markedly reduced the symptoms of diabetic pathologies, including cataract formation, vascular damage, and polyneuropathy. To develop a better understanding of the preventative and therapeutic potentials of LA, much of the current interest is focused on elucidating its molecular mechanisms in redox dependent gene expression.
Collapse
Affiliation(s)
- L Packer
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90098-9121, USA.
| | | | | |
Collapse
|
22
|
Evans JL, Goldfine ID. Alpha-lipoic acid: a multifunctional antioxidant that improves insulin sensitivity in patients with type 2 diabetes. Diabetes Technol Ther 2000; 2:401-13. [PMID: 11467343 DOI: 10.1089/15209150050194279] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Alpha-Lipoic acid (LA) is a disulfide compound that is produced in small quantities in cells, and functions naturally as a co-enzyme in the pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase mitochondrial enzyme complexes. In pharmacological doses, LA is a multifunctional antioxidant. LA has been used in Germany for over 30 years for the treatment of diabetes-induced neuropathy. In patients with type 2 diabetes, recent studies have reported that intravenous (i.v.) infusion of LA increases insulin-mediated glucose disposal, whereas oral administration of LA has only marginal effects. If the limitations of oral therapy can be overcome, LA could emerge as a safe and effective adjunctive antidiabetic agent with insulin sensitizing activity.
Collapse
Affiliation(s)
- J L Evans
- Medical Research Institute, San Bruno, California 94066, USA.
| | | |
Collapse
|
23
|
Khanna S, Roy S, Packer L, Sen CK. Cytokine-induced glucose uptake in skeletal muscle: redox regulation and the role of alpha-lipoic acid. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:R1327-33. [PMID: 10233023 DOI: 10.1152/ajpregu.1999.276.5.r1327] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In L6 myotubes, glucose uptake stimulated by interferon (IFN)-gamma or lipopolysaccharides (LPS) and a combination of LPS, IFN-gamma, and tumor necrosis factor (TNF)-alpha was inhibited by the antioxidant pyrrolidinedithiocarbamate and potentiated in reduced glutathione (GSH)-deficient cells. Also, the stimulatory effect of LPS and IFN-gamma individually, and of a combination of LPS, IFN-gamma, and TNF-alpha, on glucose uptake was associated with an increased level of intracellular oxidants (dichlorofluorescein assay) and loss of intracellular GSH. Study of the individual effects of LPS, IFN-gamma, and TNF-alpha as well as of a combination of the three activators provided evidence against a role of nitric oxide in mediating the stimulatory effect of the above-mentioned agents on glucose uptake. We also observed that the insulin-mimetic nutrient alpha-lipoic acid (LA; R-enantiomer) is able to stimulate glucose uptake in cytokine-treated cells that are insulin resistant. This study shows that cytokine-induced glucose uptake in skeletal muscle cells is redox sensitive and that, under conditions of acute infection that is accompanied with insulin resistance, LA may have therapeutic implications in restoring glucose availability in tissues such as the skeletal muscle.
Collapse
Affiliation(s)
- S Khanna
- Department of Molecular and Cell Biology, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3200, USA
| | | | | | | |
Collapse
|