Efficacy of alpha-lipoic acid in patients with burning mouth syndrome compared to that of placebo or other interventions: a systematic review with meta-analyses

Burning mouth syndrome (BMS) is a chronic oral disorder of unknown etiology which presents therapeutic challenges. Alpha-lipoic acid (ALA) has been studied as a potential treatment for BMS. The objective of this systematic review and meta-analysis was to evaluate the effectiveness of ALA compared to that of placebo or other interventions in individuals with BMS. Randomized controlled trials (RCT) using ALA to treat BMS were identified from MEDLINE, Cochrane Library, EMBASE, and Web of Science up to February 3, 2021. The assessment of the risk of bias in the included studies was based on the Cochrane guidelines. The primary outcome evaluated was the visual analog scale (VAS) pain intensity. ALA was compared with placebo, clonazepam, gabapentin, pregabalin, ALA plus gabapentin, capsaicin, Biotène^®, and laser therapy. Altogether, 137 records were scanned for inclusion/exclusion, and nine RCTs (two unclear and seven at high risk of bias) were included in the qualitative and quantitative analyses, with a total of 594 patients with BMS included in this review. All studies reported an improvement in VAS pain scores ranging from -0.72 to -2.77. Meta-analysis results showed a non-significant reduction in pain intensity for ALA (P = 0.616) compared to that of placebo on a VAS of 0-10. Patients taking ALA were 1.923 times more likely to show an improvement in self-reported BMS symptoms (P = 0.031) than those in the placebo group. Clonazepam and pregabalin showed a significant VAS pain reduction of 4.08 and 4.68 (P < 0.001), respectively, compared to that with ALA. Although ALA intervention provided a non-significant improvement in the pain score and was more likely to produce a reduction in BMS symptoms, the evidence was of low quality. Further research is needed to establish clear guidelines for the use of ALA for BMS treatment.

Alpha-Lipoic Acid Ameliorates Sperm DNA Damage and Chromatin Integrity in Men with High DNA Damage: A Triple Blind Randomized Clinical Trial

OBJECTIVE

Evidence suggests the contributory role of oxidative stress (OS) to sperm DNA damage and eventually, male infertility. Antioxidant supplementation has exhibited favorable results regarding seminal OS, sperm DNA damage, and chromatin integrity. We aimed to evaluate the effect of alpha-lipoic acid (ALA) supplementation on semen analysis, sperm DNA damage, chromatin integrity, and seminal/intracellular OS in infertile men with high sperm DNA damage.

MATERIALS AND METHODS

In this randomized triple-blind placebo-controlled clinical trial study, we opted for a triple-blind controlled clinical trial design. Considering the study's inclusion criteria for the level of sperm DNA fragmentation (higher than the threshold of 30 and 15%), 70% of participants were selected for this clinical research study. Subjects were divided into case and control groups receiving oral ALA (600 mg/day) and placebo for eighty days, respectively. Sperm parameters and functional tests were examined and compared before and after treatment. The final sample size was 34 and 29 for ALA and placebo receivers, respectively.

RESULTS

No significant differences were observed about anthropometrics and baseline measures of semen analysis, DNA damage, OS, and chromatin integrity between the two groups. Conventional semen parameters were enhanced insignificantly in both groups (P>0.05). DNA damage decreased significantly in the ALA group, as per sperm chromatin structure assay (SCSA, P<0.001). Moreover, chromomycin A3 (CMA3) staining results indicated a decrease in nuclear protamine deficiency post-ALA therapy (P=0.004). Lipid peroxidation decreased significantly after treatment with ALA (P=0.003). Further, seminal antioxidant capacity/activity did not differ significantly in either of the groups (registration number: IRCT20190406043177N1).

CONCLUSION

An 80-day course of oral ALA supplementation (600 mg/day) alleviates sperm OS, DNA damage, and chromatin integrity in men with high sperm DNA damage.

The synergic effects of alpha-lipoic acid supplementation and electrical isotonic contraction on anthropometric measurements and the serum levels of VEGF, NO, sirtuin-1, and PGC1-α in obese people undergoing a weight loss diet

Background: The anti-obesity effects of Alpha-lipoic acid (α-LA) and isotonic contraction has been reported. However, the underlying mechanism is not fully understood. This study aimed to investigate the effect of 1200 mg/day α-LA supplementation and 3 sessions per week of Faradic (an electrical stimulating system) on anthropometric parameters, body composition, VEGF, Sirtuin-1, nitric oxide (NO), and PGC1-α in obese people undergoing a weight loss regime.Methods: This randomised clinical trial was carried out on 100 obese adults. The subjects were randomly assigned to four groups of 25 subjects including Faradic, α-LA, α-LA + Faradic, and control. A Bio Impedance Analyser (BIA) was used to estimate anthropometric measurements including weight, body mass index (BMI), fat mass, and fat free mass. The serum levels of Sirtuin-1, PGC1-α, VEGF, and NO levels were measured. All measurements were done at baseline and after 8 weeks of the intervention.Results: A significant weight reduction was observed in all four groups compared to baseline (p<.01). The placebo group had significantly higher weight, BMI, weight circumstance (WC), and body fat (BF) compared with the other groups. The α-LA + Faradic group had significantly lower weight, BMI, BF, WC than control, faradic, and α-LA groups and higher, Sirtuin and PGC than the control group (all p < .05).Conclusions: The findings indicated that the α-LA and Faradic interventions may have a synergistic effect on weight, BMI, BF, WC, and SLM, possibly through changes in serum level of VEGF, NO, and PGC. Further studies are warranted to clarify the mutual effects of -α-LA and Faradic on obesity and its molecular mechanisms. Name of the registry: Iranian Registry of Clinical TrialsTrial registration number: IRCT20131117015424N2Date of registration: 04/04/2018URL of trial registry record: https://www.irct.ir/search/result?query=IRCT20131117015424N2.

Role of alpha-lipoic acid in counteracting paclitaxel- and doxorubicin-induced toxicities: a randomized controlled trial in breast cancer patients

BACKGROUND AND OBJECTIVE

Paclitaxel and doxorubicin are associated with neurotoxicity and cardiotoxicity respectively. This study aimed at investigating the role of alpha-lipoic acid (ALA) in counteracting paclitaxel-induced neuropathy and doxorubicin-associated cardiotoxicity in women with breast cancer.

PATIENTS AND METHODS

This randomized double-blind placebo-controlled prospective study included 64 patients with breast cancer who were randomized into control group (n = 32) which received 4 cycles of doxorubicin plus cyclophosphamide (every 21 days) followed by weekly doses of paclitaxel for 12 weeks plus placebo tablets once daily and ALA group (n = 32) which received the same chemotherapeutic regimen plus ALA 600 once daily for 6 months. Patients were assessed by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE version 4.0) for grading of neuropathy and by 12-item neurotoxicity questionnaire (Ntx-12). The assessment included also echocardiography and evaluation of serum levels of brain natriuretic peptide (BNP), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), and neurotensin (NT). Data were analyzed by paired and unpaired t-test, Mann-Whitney U test, and chi-square test.

RESULTS

As compared to placebo, ALA provoked significant improvement in NCI-CTCAE neuropathy grading and Ntx-12 score after the end of 9th and 12th weeks of paclitaxel intake (p = 0.039, p = 0.039, p = 0.03, p = 0.004, respectively). At the end of the chemotherapy cycles, ALA resulted in significant decline in serum levels of BNP, TNF-α, MDA, and neurotensin (p < 0.05) as compared to baseline data and placebo.

CONCLUSION

Alpha-lipoic acid may represent a promising adjuvant therapy to attenuate paclitaxel-associated neuropathy and doxorubicin-induced cardiotoxicity in women with breast cancer.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03908528.

Alpha-Lipoic Acid Protects Against Doxorubicin-Induced Cardiotoxicity by Regulating Pyruvate Dehydrogenase Kinase 4

As a widely used anti-tumor anthracycline, the accumulation of Doxorubicin (DOX) in body causes irreparable cardiomyocyte damage and therefore is limited in clinical application. Strategies to prevent from DOX-associated cardiotoxicity are urgent for patients who undergo DOX-based chemotherapy. Since oxidative stress injury being the major reason for myocardial toxicity of DOX, here we demonstrated that, Alpha-lipoic acid (ALA), which is a reductive agent, plays a cardioprotective role in attenuating DOX-induced cardiotoxicity by inhibiting pyruvate dehydrogenase kinase 4 (PDK4) expression. In vivo, the beneficial effect of ALA was evidenced by increased survival rate, mechanical contraction, and oxidative phosphorylation, while decreased reactive oxidative species (ROS) and apoptosis. In vitro, PDK4 overexpression remarkably increased DOX-induced apoptosis and ROS production in H9C2 cells. Notably, the protective effect of ALA was abrogated by PDK4 overexpression. We further used PDK4 knockout mice to identify the role of PDK4 in DOX-induced cardiotoxicity. Results elicited that PDK4 deficiency showed a consistent effect in protecting DOX cardiotoxicity as ALA treatment, which was evidenced by restored redox homeostasis and mitochondrial metabolism, finally inhibited myocardial injury. In conclusion, the cardioprotective role of ALA against DOX cardiotoxicity was dependent on PDK4-mediated regulation of oxidative stress and mitochondria metabolism.

Combination of alpha lipoic acid and metformin supplement improve assisted reproductive technologies outcomes in polycystic ovary syndrome patients

We aimed to investigating the effects of metformin (MET) in combination with alpha lipoic acid (ALA) on hormonal and biochemical parameters, in polycystic ovary syndrome (PCOS) women undergoing intracytoplasmic sperm injection (ICSI). This experimental pilot study with a randomized design was carried out on 40 PCOS women in two groups: (1) MET group, administered 1,500 mg/day MET, and (2) MET (1,500 mg/day)+ALA (1,800 mg/day) group. Drugs were administered from the third day of the previous cycle until the day of oocyte aspiration (six weeks of treatment in total). MET+ALA significantly increased the number of maturated oocytes and the rate of fertilization when compared to the MET group. Combination MET+ALA could increase significantly the number of oocytes retrieval and the number of good-quality embryos. Also, the malondialdehyde (MDA) level decreased significantly in the MET+ALA group and the total antioxidant capacity (TAC) level increased significantly in the MET+ALA group compared to the MET group. Also, fasting blood sugar (FBS), insulin, luteinizing hormone (LH), and LH/follicle stimulating hormone (FSH) levels were significantly lower in the MET+ALA group. The pregnancy outcomes showed no significant difference in the rates of biochemical pregnancy, clinical pregnancy, miscarriage, and live births between the control and study groups. The combination of MET+ALA treatment could moderate the complications of PCOS and subsequently improve oocyte and embryo quality.

Thioctamer: a novel thioctic acid-glatiramer acetate nanoconjugate expedites wound healing in diabetic rats

The current work aims to design thioctic acid (TA) and glatiramer acetate (GA) nanoconjugate (thioctamer) loaded hydrogel formula as well as evaluation of thioctamer preclinical efficacy in expediting wound healing in a rat model of the diabetic wound. Thioctamer was prepared by conjugation of GA and TA in a 1:1 molar ratio. Particle size, zeta potential, and thermodynamic stability of the prepared thioctamer were assessed. Thioctamer was loaded in hydroxypropyl methylcellulose-based hydrogel and in vitro release study was investigated. The ability of thioctamer to enhance the process of wound healing in diabetic rats was investigated by assessing wound contraction and immunohistochemical assessment of the inflammation markers IL-6 and TNF-α. The results demonstrated that thioctamer showed particle size of 137 ± 21.4 nm, polydispersity index (PDI) of 0.235, and positive zeta potential value of 7.43 ± 4.95 mV. On day 7 of making a skin excision, diabetic rat wounds administered thioctamer preparation showed almost complete healing (95.6 ± 8.6%). Meanwhile, % of wound contraction in animals treated with TA or GA groups exhibited values amounting to 56.5 ± 5.8% and 62.6 ± 7.1%, respectively. Histological investigation showed that the highest healing rate was noted in the thioctamer group animals, as the surface of the wound was nearly fully protected by regenerated epithelium with keratinization, with few inflammatory cells noticed. Thioctamer significantly (p<.05) inhibited IL-6 and TNF-α expression as compared with sections obtained from the negative control, TA, GA, or positive control group animals on day 7. The evidence of the ability of thioctamer to significantly expedite wound healing in the diabetic rats is presented.

Alpha-lipoic acid potentiates the anti-arrhythmic effects of ischemic postconditioning in the setting of cardiac ischemia/reperfusion injury in diabetic rats

Background

Prevention of lethal ventricular arrhythmias induced by myocardial ischemia/reperfusion (I/R) in diabetic patients is the major goal of cardioprotective strategies. Here, we aimed to examine the anti-arrhythmic effect of ischemic postconditioning (IPostC) and alpha-lipoic acid (ALA) in myocardial I/R injury of type-II diabetic rats, focusing on the involvement of connexin-43 and nitric oxide (NO) in this context.

Methods

Diabetes (duration of 12 weeks) was induced by high-fat diet and low dose of streptozotocin in thirty male Wistar rats (12 weeks old, 200-250 g). After mounting the hearts on the Langendorff apparatus, I/R was induced by the ligation of left anterior descending coronary artery for 35 min, and reperfusion for 60 min. ALA (100 mg/kg/day) was administered orally in diabetic rats for five weeks before I/R. IPostC was applied immediately at early reperfusion. The arrhythmias were evaluated according to the Lambeth convention. Connexin-43 expression and NO levels were assessed by western blotting and Griess calorimetric method, respectively.

Results

IPostC could not significantly decrease the number, duration, and incidence of premature ventricular contraction, ventricular tachycardia, and ventricular fibrillation, also the severity of arrhythmias in diabetic hearts. However, IPostC in combination with ALA-preconditioning significantly decreased the above mentioned parameters compared with untreated or monotherapies-received diabetic rats (P < 0.05 to P < 0.001). Furthermore, this combination therapy significantly increased connexin-43 expression and NO levels, compared with untreated diabetic rats (P < 0.01).

Conclusion

Preconditioning with ALA restored anti-arrhythmic effect of IPostC in diabetic hearts. Increased connexin-43 expression and NO levels may be the key players in this cardioprotection.

Diverse impact of N-acetylcysteine or alpha-lipoic acid supplementation during high-fat diet regime on fatty acid transporters in visceral and subcutaneous adipose tissue

PURPOSE

Adipose tissue's (AT) structural changes accompanying obesity may alter lipid transport protein expression and, thus, the fatty acids (FAs) transport and lipid balance of the body. Metabolic abnormalities within AT contribute to the elevated production of reactive oxygen species and increased oxidative/nitrosative stress. Although compounds such as N-acetylcysteine (NAC) and α-lipoic acid (ALA), which restore redox homeostasis, may improve lipid metabolism in AT, the mechanism of action of these antioxidants on lipid metabolism in AT is still unknown. This study aimed to examine the impact of NAC and ALA on the level and FA composition of the lipid fractions, and the expression of FA transporters in the visceral and subcutaneous AT of high-fat diet-fed rats.

MATERIALS AND METHODS

Male Wistar rats were randomly divided into four groups. The mRNA levels and protein expression of FA transporters were assessed using real-time PCR and Western Blot analyses. The collected samples were subjected to histological evaluation. The level of lipids (FFA, DAG, and TAG) was measured using gas-liquid chromatography.

RESULTS

We found that antioxidants affect FA transporter expressions at both the transcript and protein levels, and, therefore, they promote changes in AT's lipid pools. One of the most remarkable findings of our research is that different antioxidant molecules may have a varying impact on AT phenotype.

CONCLUSION

NAC and ALA exert different influences on AT, which is reflected in histopathological images, FA transport proteins expression patterns, or even the lipid storage capacity of adipocytes.

Biochemical, molecular and cytological impacts of alpha-lipoic acid and Ginkgo biloba in ameliorating testicular dysfunctions induced by silver nanoparticles in rats

Silver nanoparticles (AgNPs) are commonly utilized in medicine. However, they have negative effects on the majority of organs, including the reproductive system. AgNPs were reported to be able to reach the testicular tissues due to their nano size, which allows them to pass through blood-testicular barriers. The goal of this study was to see if alpha-lipoic acid (LA) or Ginkgo biloba (GB) might protect adult rat testes after intraperitoneal injection of AgNPs. Forty male healthy adult Wister albino rats were randomly assigned to four groups: control, AgNPs-intoxicated group intraperitoneally injected AgNPs 50 mg/kg b.w, 3 times a week; LA + AgNPs group intoxicated with AgNPs and orally gavaged with 100 mg LA/kg b.w; and GB + AgNPs group injected with AgNPs and orally given GB extract 120 mg/kg b.w for 30 consecutive days. Biochemical changes (testosterone, ACP, and prostatic acid phosphatase), oxidative indices, mRNA expression of proapoptotic (BAX) and anti-apoptotic (BCL-2) biomarkers, histological, and immunohistochemical changes in testicular tissues were investigated. Significant decrease in serum testosterone level and elevation in ACP and PACP enzyme activity in AgNPs-treated rats. As well, there were lowering in tGSH, GSH GR, GPx, and elevation in MDA and GSSG values. AgNPs-exposed rats expressed downregulation of testicular thirodexin-1 (Txn-1), transforming growth factor-1β (TGF-1β), anti-apoptotic (BCL-2), and upregulaion of proapoptotic biomarkers (BAX) mRNA expressions. Strong positive action to BAX and lowering the action of Ki-67 antibody were observed. Because of their antioxidant, anti-inflammatory, and anti-apoptotic properties, cotreatment with LA or GB could be beneficial in reducing the harmful effects of AgNPs on the testicles.

Alpha-lipoic acid improved motor function in MPTP-induced Parkinsonian mice by reducing neuroinflammation in the nigral and spinal cord

Parkinson's disease (PD) is a chronic neurodegenerative movement disorder, resulting in dopaminergic (DA) neuronal loss in the substantia nigra (SN) and injury of extranigral spinal cord neurons. This study was to investigate the effect of α-lipoic acid (ALA) on 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) induced neuroinflammation in the substantia nigra and spinal cord as well as motor function of the mice with PD. After MPTP induced mouse model with PD, the effect of ALA on motor defects was evaluated by measurement of fore and hind limb step length and suspension test. The effects of ALA on microglia in the SN and spinal cord of MPTP-induced Parkinsonian mice were detected by immunofluorescence. The effect of ALA on the protein level nuclear factor-κB (NF-κB) in MPTP-induced mice with PD were examined by Western blot. RT-qPCR was used to detect the effect of ALA on gene expression of tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) in the SN and spinal cord of MPTP-induced mice. The behavioral results showed that ALA treatment significantly increased the step length and suspension time of MPTP-induced mice (P < 0.05). Immunofluorescence results showed that ALA significantly reduced MPTP-induced activation of microglia both in the SN and spinal cord (P < 0.05). Western blot and RT-qPCR showed that ALA significantly reduced the expression of NF-κB, TNF-α and iNOS in the nigra and spinal cord (P < 0.05). ALA can play a neuroprotective role through alleviating the activation of microglia, reducing neuroinflammation in the nigra and extranigra of mice induced by MPTP and therefore improving their motor dysfunction.

α-Lipoic Acid, an Organosulfur Biomolecule a Novel Therapeutic Agent for Neurodegenerative Disorders: An Mechanistic Perspective

Lipoic acid (α-LA) (1,2-dithiolane3-pentanoic acid (C₈H₁₄O₂S₂) is also called thioctic acid with an oxidized (disulfide, LA) and a reduced (di-thiol: dihydro-lipoic acid, DHLA) form of LA. α-LA is a potent anti-oxidative agent that has a significant potential to treat neurodegenerative disorders. α-LA is both hydrophilic and hydrophobic in nature. It is widely distributed in plants and animals in cellular membranes and in the cytosol, which is responsible for LA's action in both the cytosol and plasma membrane. A systematic literature review of Bentham, Scopus, PubMed, Medline, and EMBASE (Elsevier) databases was carried out to understand the Nature and mechanistic interventions of the α-Lipoic acid for central nervous system diseases. Moreover, α-LA readily crosses the blood-brain barrier, which is a significant factor for CNS activities. The mechanisms of α-LA reduction are highly tissue-specific. α-LA produces its neuroprotective effect by inhibiting reactive oxygen species formation and neuronal damage, modulating protein levels, and promoting neurotransmitters and anti-oxidant levels. Hence, the execution of α-LA as a therapeutic ingredient in the therapy of neurodegenerative disorders is promising. Finally, based on evidence, it can be concluded that α-LA can prevent diseases related to the nervous system.

Alpha-Lipoic Acid Attenuates MPTP/MPP+-Induced Neurotoxicity: Roles of SIRT1-Dependent PGC-1α Signaling Pathways

Accumulated oxidative damage plays key roles in the pathogenesis of Parkinson's disease (PD). Silent mating type information regulation 2 homolog 1 (SIRT1), a class III histone deacetylase, can directly activate peroxisome proliferator-activated receptor-c coactivator-1α (PGC-1α) and attenuate oxidative stress. Alpha-lipoic acid (ALA) is a natural antioxidant that has been demonstrated to protect PC12 cells against 1-methyl-4-phenylpyridinium (MPP⁺). However, the underlying mechanisms related to changes in cell signaling cascades are not fully understood. In the present study, the neuroprotective effect of ALA and the potential role of ALA in the SIRT1 pathway was investigated in vitro and in a mouse model of PD. A Cell Counting Kit-8 (CCK-8) assay was performed to detect the SY5Y-SH cell viability. Immunohistochemistry, quantitative real-time polymerase chain reaction and western blot assays were used to evaluate the expression of tyrosine hydroxylase (TH), SIRT1, and PGC-1α in vivo and in vitro. Intracellular reactive oxygen species (ROS) production and tissue SOD and MDA were detected by the corresponding assay kits. The results showed that ALA notably prevented oxidative stress and neurotoxicity in vivo and in vitro against 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)/MPP⁺. Furthermore, ALA significantly increased the expression of SIRT1 and PGC-1α in vivo and in vitro in MPTP/MPP⁺-induced models, which was reversed by the SIRT1 inhibitor EX527. These results suggested that ALA prevented oxidative stress and that neurotoxicity was involved in the upregulation of SIRT1 and PGC-1α in PD mice.

Alpha-lipoic acid analogues in the regulation of redox balance in epilepsy: A molecular docking and simulation study

OBJECTIVE

Oxidative stress is one of the pathophysiological mechanisms implicated in drug-resistant epilepsy. Recurrent seizures and prolonged treatment with anti-seizure medicines (ASMs) can produce reactive oxygen species (ROS) resulting in neuronal cell damage, cell toxicity, and cell death. This damage may contribute to the loss of efficacy of anti-seizure medicines. Add-on therapy with antioxidants, neuroimmunophilins, and polyphenols may thus be beneficial in drug-resistant epilepsy. In vitro and in vivo studies have shown a significant improvement in drug efficacy and seizure suppression using co-treatment of anti-seizure medication with naturally available antioxidants including alpha-lipoic acid (α-lipoic acid) from walnut; however, the underlying mechanisms of action remain to be fully understood.

METHODS

We undertook molecular docking and molecular dynamics simulations to determine whether alpha-lipoic acid and related analogues interacted with the human manganese superoxide dismutase (MnSOD) protein, a member of the oxidative metabolic pathway. The 3D structure of the compounds and the protein were retrieved from protein and chemical databases, binding sites were identified and ligand-protein interactions were performed.

RESULTS

Alpha-lipoic acid and various analogues docked within a human MnSOD binding region. Docking results were validated by molecular dynamic simulation. The CMX-2043 analogue showed strong binding with MnSOD compared to alpha-lipoic acid and other analogues.

SIGNIFICANCE

Our findings provide new insights into additional mechanisms of action, which may in part, account for the antioxidant properties associated with alpha-lipoic acid and related analogues. The results support further in vitro and in vivo evaluation of these compounds to better understand their potential as add-on therapy for ASM treatment in epilepsy.

Decrypting the potential role of α-lipoic acid in Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases with motor disturbances, cognitive decline, and behavioral impairment. It is characterized by the extracellular aggregation of amyloid-β plaques and the intracellular accumulation of tau protein. AD patients show a cognitive decline, which has been associated with oxidative stress, as well as mitochondrial dysfunction. Alpha-lipoic acid (α-LA), a natural antioxidant present in food and used as a dietary supplement, has been considered a promising agent for the prevention or treatment of neurodegenerative disorders. Despite multiple preclinical studies indicating beneficial effects of α-LA in memory functioning, and pointing to its neuroprotective effects, to date only a few studies have examined its effects in humans. Studies performed in animal models of memory loss associated with aging and AD have shown that α-LA improves memory in a variety of behavioral paradigms. Furthermore, molecular mechanisms underlying α-LA effects have also been investigated. Accordingly, α-LA shows antioxidant, antiapoptotic, anti-inflammatory, glioprotective, metal chelating properties in both in vivo and in vitro studies. In addition, it has been shown that α-LA reverses age-associated loss of neurotransmitters and their receptors. The review article aimed at summarizing and discussing the main studies investigating the neuroprotective effects of α-LA on cognition as well as its molecular effects, to improve the understanding of the therapeutic potential of α-LA in patients suffering from neurodegenerative disorders, supporting the development of clinical trials with α-LA.

Safety and efficacy of alpha-lipoic acid oral supplementation in the reduction of pain with unknown etiology: A monocentric, randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

Extensive evidence suggests that alpha-lipoic acid (ALA) is effective in diabetic neuropathy pain management. However, little is known on its safety and efficacy in reducing idiopathic pain in normoglycemic subjects. The aim of this study was to evaluate ALA food supplement safety and efficacy in the reduction of different forms of idiopathic pain.

METHODS

Two-hundred and ten normoglycemic adults suffering from idiopathic pain (i.e. 57 subjects with primitive neuropathic pain, 141 subjects with arthralgia with unknown etiology, and 12 subjects with idiopathic myalgia) were randomized to receive placebo, 400 mg/day, or 800 mg/day of ALA. Participants underwent two visits (at baseline = t0, and after 2 months = t1) in which two validated questionaries for pain (numerical rating scale [NRS] and visual analogue scale [VAS]) were collected; fasting blood glucose assessment, adverse effects, and renal and hepatic toxicity were also monitored.

RESULTS

At t1, none of subjects treated with ALA reported a decreased glycemia or adverse effects. The treated subjects showed a significant reduction in NRS (p < 0.001) while the placebo group did not show any NRS reduction (p = 0.86). Similar results were also obtained for VAS. Statistical analysis aimed at detecting possible differences in NRS and VAS scores among treatment groups based on the source of pain did not reveal any significant effect.

CONCLUSIONS

Since the management of idiopathic pain is challenging for physicians, the use of ALA food supplements could be a feasible option, based on its safety and efficacy compared to commonly-used analgesic drugs.

Effects of dietary supplementation with alpha-lipoic acid on apparent digestibility and serum metabolome alterations of sheep in summer

To investigate the effects of alpha-lipoic acid (LA) on the nutrition metabolism of sheep (36.72 ± 1.44 kg) in the summer, twenty-one sheep were randomly assigned to three treatments addressing LA supplementation: 0.00 (CTL), 600 (LA-L), and 900 (LA-H) mg/kg of dry matter (DM) per day for each sheep. Whole feces and urine collection methods were used to analyze apparent digestibility; ELISA kits to determine the hormones, antioxidant, and immune parameters in the blood; and serum metabolomics to detect and analyze small molecular substances. The results showed the DM intakes in the LA-L and LA-H groups were significantly increased by 8.22% and 8.02%, respectively, compared to that in the CTL group, and there was no significant effect on average daily gain, feed conversion ratio, nitrogen digestibility, calcium digestibility, and phosphorus digestibility. Regarding hormones, antioxidant, and immune indicators, the concentrations of triiodothyronine, superoxide dismutase, glutathione reductase, HSP70, and IgA significantly increased after LA supplementation, while adrenaline and malondialdehyde levels significantly decreased. With the pairwise comparison of the three groups, metabolomics analysis identified 22 differential metabolites in the positive/negative modes, respectively, which suggested LA supplementation can significantly affect sheep's lipid, amino acid, and nucleic acid metabolism. Additionally, 3-indolepropionic acid, cinnamoylglycine, butyric acid, dodecanedioic acid, indoxyl sulfate, and pantothenic acid were the common differential metabolites with higher concentrations after LA supplementation. In summary, dietary supplementation of LA can increase the sheep's DMI, energy digestibility, antioxidant capacity, and immunity. These changes provide evidence to support the use of LA supplementation for livestock.

Alpha lipoic acid supplementation affects serum lipids in a dose and duration-dependent manner in different health status

Background: Many studies have investigated the effect of ALA supplementation on lipid profile, and different results have been obtained from these studies. The current systematic review and dose-response meta-analysis was conducted to achive a strong conclusion about the effect of ALA supplementation on lipid profile including total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL, HDL) and triglyceride (TG). Methods: A systematic search was performed in PubMed, SCOPUS, ProQuest and Embase for randomized placebo-controlled human trials that examined the effect of ALA supplementation on lipid profile up to November 2020. The dose and duration of ALA supplementation for included studies were ranged between 300-1200 mg/d and 2-16 weeks respectively. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were used to evaluate the effect size. Cochran's Q and I² tests were also used to assess between-study's heterogeneity. In addition, subgroup analysis was performed to investigate potential sources of heterogeneity. Dose-response relationship was done using fractional polynomial modeling. Results: Among all eligible studies, 12 studies with a total number of 548 participants were selected. ALA caused a significant reduction on TC (WMD): -10.78 mg/dl, 95% CI: -20.81, -0.74, P=0.002), LDL (WMD: -10.88 mg/dl, 95% CI: -19.52, -2.24, P=0.014) and TG (WMD: -31.02 mg/dl, 95% CI: -49.63, -12.42, P<0.001). There was also a non-significant increaes in HDL concentrations. In addition, dose-response analysis showed a positive association between LDL (P_{non-linearity}=0.026), TG (P_{non-linearity}<0.001) and duration of intervention in a non-linear model. Conclusion: The present meta-analysis revealed the beneficial effects of ALA supplementation on TC, LDL and TG levels. Moreover, the beneficial effects of ALA supplementation on LDL and TG levels was duration-dependent.

Alpha lipoic acid ameliorates scopolamine induced memory deficit and neurodegeneration in the cerebello-hippocampal cortex

Scopolamine- induced memory loss is used to study new drug discovery in Alzheimer's disease (AD) pathogenesis. This study was aimed at evaluating the role of an antioxidant supplement alpha-lipoic acid (AHA), in ameliorating the oxidative damaging effects of scopolamine on cognition, memory, and the neurohistology of the cerebello-hippocampal cortex. Twenty adult male Wistar rats used were categorized into four (4) groups (n = 5): Group A- Control, Group B- 200 mg/kg of AHA, Group C- Scopolamine (memory-impaired model), and Group D- Neurodegenerative repair model (Scopolamine + AHA). The treatment lasted for fourteen (14) days. Y-maze and hang-wire (limb use test) were used as behavioural index to assess memory and motor function while brain tissues were processed for histology (H and E stain), histochemistry using Cresyl Fast violet stain for Nissl bodies, and immunohistochemistry of astrocytes using glial fibrillary acidic protein (GFAP). Results showed that scopolamine led to a decline in brain weight, impaired memory and motor function, induced oxidative tissue damage cumulating in loss of neuronal cells, chromatolysis, the proliferation of reactive astrocytes (neuroinflammation biomarker) in the cerebello-hippocampal cortex; but upon administration of AHA these neuropathological characterizations were inhibited and reversed by AHA demonstrating its antioxidant and neuro- repair potential. In conclusion, AHA is a useful therapeutic agent against scopolamine-induced cognitive and memory deficit because it has the ability to ameliorate oxidative tissue damage by attenuating reactive astrocytes proliferation and neuron chromatolysis thereby improving memory and motor function.

Oral Alpha Lipoic Acid Treatment for Symptomatic Diabetic Peripheral Neuropathy: A Randomized Double-Blinded Placebo-Controlled Study

BACKGROUND

Alpha-lipoic acid (ALA) was used in the treatment of diabetic peripheral neuropathy (DPN) using different routes, doses and treatment durations. The aim of this work is to assess the efficacy of oral 600mg ALA twice daily over 6 months in the treatment of patients with DPN.

METHODS

This is a prospective, single-center, double-blinded, placebo-controlled study conducted at the outpatient clinic of Mansoura Specialized Hospital, Mansoura University. A total of 200 patients with DPN were randomly assigned to add on treatment with either oral 600mg twice daily ALA (n=100) or placebo (n=100) for 6 months. Treatment outcome was assessed using vibration perception threshold (VPT), neurological symptom score (NSS), neurological disability score (NDS), and visual analog scale (VAS) for pain at baseline and at each visit (1, 3 and 6 months) after the start of treatment.

RESULTS

Comparison between the study groups regarding the baseline data revealed no statistically significant differences. with respect to the outcome parameters, no significant differences were found between the studied groups at baseline. However, in subsequent visits, ALA-treated patients had significantly better results regarding almost all the outcome parameters (NSS, NDS, VAS, VPT). Mild nausea was reported in 6 patients. None of the studied patients discontinued treatment.

CONCLUSION

Oral 600mg ALA twice-daily treatment for DPN over 6 months is effective, safe and tolerable.

Alpha-lipoic acid could attenuate the effect of chemerin-induced diabetic nephropathy progression

Objective(s):

Chemerin is associated with insulin resistance, obesity, and metabolic syndrome. α-lipoic acid (α-LA) is a potent antioxidant involved in the reduction of diabetic symptoms. This study aimed to investigate the relationship between chemerin and P38 MAPK in the progression of diabetic nephropathy (DN) and examine the effects of α-LA on chemerin-treated human mesangial cells (HMCs).

Materials and Methods:

HMCs were transfected with a chemerin-overexpressing plasmid. HMCs were also treated with high-glucose, chemerin, α-LA, PDTC (pyrrolidine dithiocarbamate ammonium, NF-κB p65 inhibitor), and/or SB203580 (P38 MAPK inhibitor). Cell proliferation was tested using the Cell Counting Kit-8 assay. Collagen type IV and laminin were tested by ELISA. Chemerin expression was detected by qRT-PCR. The chemerin receptor was detected by immunohistochemistry. Interleukin-6 (IL-6), tumor necrosis factor-a (TNF-α), nuclear factor-κBp-p65 (NF-κB p-p65), transforming growth factor-β (TGF-β), and p-P38 mitogen-activated protein kinase (p-P38 MAPK) were evaluated by western blot.

Results:

High-glucose culture increased the expression of the chemerin receptor. α-LA inhibited HMC proliferation. Chemerin overexpression increased collagen type IV and laminin expression. P38 MAPK signaling was activated by chemerin, resulting in up-regulation of IL-6, TNF-α, NF-κB p-p65, and TGF-β. SB203580, PDTC, and α-LA reversed the effects of chemerin, reducing IL-6, TNF-α, NF-κB p-p65, and TGF-β expression.

Conclusion:

Chemerin might be involved in the occurrence and development of DN. α-LA might prevent the effects of chemerin on the progression of DN, possibly via the P38 MAPK pathway.

Protective effects of alpha-lipoic acid on hair cell damage in diabetic zebrafish model

Hearing impairment is one of the complications in diabetes mellitus; however, there are very few therapeutic studies on it. In this study, we investigated the protective effect of alpha-lipoic acid (ALA) on hearing loss in diabetic transgenic zebrafish and confirmed that ALA protects the loss of hair cells (HCs) caused by hyperglycemia. The data indicated that ALA has a protective effect on the damage to HCs in diabetic zebrafish.

Alpha-lipoic acid attenuates silica-induced pulmonary fibrosis by improving mitochondrial function via AMPK/PGC1α pathway activation in C57BL/6J mice

Silicosis is characterized by pulmonary interstitial fibrosis that arises as a result of chronic exposure to silica. The few available treatments only delay its progression. As α-lipoic acid (ALA) has been shown to have various beneficial effects, including mitoprotective, antioxidant, and anti-inflammatory effects, we hypothesized that it may exhibit therapeutic effects in pulmonary fibrosis. Therefore, in the present study, we used a murine model of silicosis to investigate whether supplementation with exogenous ALA could attenuate silica-induced pulmonary fibrosis by improving mitochondrial function. ALA was administered to the model mice via continuous intragastric administration for 28 days, and then the antioxidant and mitoprotective effects of ALA were evaluated. The results showed that ALA decreased the production of reactive oxygen species, protected mitochondria from silica-induced dysfunction, and inhibited extracellular matrix deposition. ALA also decreased hyperglycemia and hyperlipidemia. Activation of the mitochondrial AMPK/PGC1α pathway might be responsible for these ALA-mediated anti-fibrotic effects. Exogenous ALA blocked oxidative stress by activating NRF2. Taken together, these findings demonstrate that exogenous ALA effectively prevents the progression of silicosis in a murine model, likely by stimulating mitochondrial biogenesis and endogenous antioxidant responses. Therefore, ALA can potentially delay the progression of silica-induced pulmonary fibrosis.

Synergistic Tumoricidal Effects of Alpha-Lipoic Acid and Radiotherapy on Human Breast Cancer Cells via HMGB1

PURPOSE

Radiotherapy (RT) is one of main strategies of cancer treatment. However, some cancer cells are resistant to radiation-induced cell death, including apoptosis. Therefore, alternative approaches targeting different anti-tumor mechanisms such as cell senescence are required. This study aimed to investigate the synergistic effect of alpha-lipoic acid (ALA) on radiation-induced cell death and senescence in MDA-MB-231 human breast cancer cells.

MATERIALS AND METHODS

The cells were divided into four groups depending on the cell treatment (control, ALA, RT, and ALA+RT). Cells were analyzed for morphology, apoptotic cell death, mitochondrial reactive oxygen species, membrane potential, cellular senescence, and cell cycle.

RESULTS

Our data showed that ALA significantly promoted apoptotic cell death when combined with RT, as reflected by Annexin V staining, expression of apoptosis-related factors, mitochondrial damages as well as cell morphological changes and reduction of cell numbers. In addition, ALA significantly enhanced radiation-induced cellular senescence, which was shown by increased HMGB1 expression in the cytosol fraction compared to the control, increased p53 expression compared to the control, activation of p38 as well as nuclear factor кB, and G2/M cell cycle arrest.

CONCLUSION

The current study is the first report showing a new mode of action (senescence induction) of ALA beyond apoptotic cell death in MDA-MB-231 cancer cells known to be resistant to RT.

Effects of Theranekron and alpha-lipoic acid combined treatment on GAP-43 and Krox-20 gene expressions and inflammation markers in peripheral nerve injury

Peripheral nerve injury (PNI) is a major health problem that results in loss of motor and sensory functions. In treatment of PNI, various methods such as anastomosis, nerve grafts, nonneural tissue grafts, and nerve conduits are applied. In the present study, it was aimed to investigate the effects of Theranekron and Alpha-lipoic acid (ALA) combined treatment on nerve healing in experimental PNI by using histomorphometric, electron microscopic, immunohistochemical and molecular biological methods. Sixty-two Wistar rats were divided into six groups; the normal control group, sham operation group, experimental control group having a crush type injury with no treatment, Theranekron treatment group, ALA treatment group and Theranekron+ALA combined treatment group. Sciatic nerve tissue samples were obtained on days 1, 7 and 14 following injury in all groups. GAP-43 expression was upregulated in all PNI received groups compared to the control group. Krox-20 expression was downregulated in all groups that received PNI compared to the control group. While intensely positive TNF-α and IL-6 expressions were observed up to the 1st to the 14th day for the experimental control group, these expressions were seen as "weakly positive" in the treatment groups from the 1st day to the 14th day. The number of myelinated fibers was higher in the control and sham operation groups. Additionally, the number of myelinated nerve fibers increased in the combined treatment group. In conclusion, these findings suggest that combined therapy of Theranekron and ALA promotes structural recovery and it should be considered as an effective treatment protocol following PNI.