The pharmacology of the antioxidant lipoic acid

Lipoic acid improves wound healing through its immunomodulatory and anti-inflammatory effects in a diabetic mouse model

Objectives

Diabetes mellitus is a chronic disease that has become more prevalent worldwide because of lifestyle changes. It leads to serious complications, including increased atherosclerosis, protein glycosylation, endothelial dysfunction, and vascular denervation. These complications impair neovascularization and wound healing, resulting in delayed recovery from injuries and an elevated risk of infections. The present study aimed to investigate the effect of lipoic acid (LA) on the key mediators involved in the wound healing process, specifically CD4 + CD25 + T cell subsets, CD4 + CD25 + Foxp3 + regulatory T (Treg) cells, T-helper-17 (Th17) cells that generate IL-17 A, glucocorticoid-induced tumor necrosis factor receptor (GITR) expressing cells, as well as cytokines such as IL-2, IL-1β, IL-6, and TNF-α and IFN-γ. These mediators play crucial roles in epidermal and dermal proliferation, hypertrophy, and cell migration.

Methods

We divided mice into 5 groups: the non-diabetic (normal control; NC), wounded non-diabetic mice (N + W), wounded diabetic mice (D + W), wounded diabetic mice treated with 50 mg/kg lipoic acid (D + W + L50) for 14 days, and wounded diabetic mice treated with 100 mg/kg lipoic acid (D + W + L100) for 14 days.

Results

Flow cytometric analysis indicated that lipoic acid-treated mice exhibited a significant decrease in the frequency of intracellular cytokines (IL-17 A, TNF-α and IFN-γ) in CD4 + T cells, as well as a reduction in the number of GITR-expressing cells. Conversely, a significant upregulation in the number CD4+, CD25+, FOXp3 + and CD4 + CD25 + Foxp3 + regulatory T (Treg) cells was observed in this group compared to both the normal + wounded (N + W) and diabetic + wounded (D + W) groups. Additionally, the mRNA Levels of inflammatory mediators (IL-2, IL-1β, IL-6, and TNF-α) were downregulated in lipoic acid-treated mice compared to other groups. T thereby he histological findings of diabetic skin wounds treated with lipoic acid showed well-healed surgical wounds.

Conclusions

These findings support the beneficial role of lipoic acid in fine-tuning the balance between anti-inflammatory and pro-inflammatory cytokines, influencing both their release and gene expression.

Binding of the commonly used antioxidants (quercetin, resveratrol, and dihydrolipoic acid) to major circulating proteins - spectroscopic and in silico docking and molecular dynamic simulation studies

Poor bioavailability and reduced stability are the main drawbacks to efficiently utilizing many naturally occurring antioxidants, so their binding to circulatory proteins is essential. This work investigated whether major human circulatory proteins, besides albumin, including transferrin, alpha-2-macroglobulin, and fibrinogen, bind widely consumed antioxidants and food supplements, including quercetin, trans-resveratrol, and dihydrolipoic acid, thus filling the gap of detailed pharmacokinetic properties of these food supplements. Detailed examination of the protein structural and functional changes that occur upon ligand binding was analyzed by spectroscopic methods and in silico docking and molecular dynamic simulation studies on the model that consists of the protein/antioxidant pair with the highest affinity constant. It was found that alpha-2-macroglobulin binds trans-resveratrol with the highest affinity (Ka of 4.5 x 104 M-1). In silico results revealed four potential binding sites between trans-resveratrol and alpha-2-macroglobulin, with hydrogen bonds being crucial for binding, while other observed interactions (primarily aromatic interactions) are of secondary importance. The binding of trans-resveratrol to alpha-2-macroglobulin leads to mutual protection of both molecules from oxidative stress and significantly increased hidrosolubility of resveratrol, both of which could serve to increase the bioavailability and bioactivity of resveratrol in circulation.

Effects of α-lipoic acid (LA) supplementation in high-fat diet on the growth, glycolipid metabolism and liver health of largemouth bass (Micropterus salmoides)

An 8-week feeding trial was conducted to investigate the effects of LA supplementation in a high-fat diet on the growth performance, hepatic antioxidant capacity, and glycogen metabolism of largemouth bass (Micropterus salmoides). Five diets were formulated including control diet (11.55 % crude fat, CF), a high-fat diet (17.80 % crude fat, HF) and three HF diets supplemented with 0.15 %, 0.20 % and 0.25 % LA (HL0.15, HL0.20 and HL0.25, respectively). In this experiments, HL0.15 and HL0.20 could improve the uniform for the growth of the largemouth bass, while adding 0.25 % did not significantly improve growth. The highest viscerosomatic index (VSI) and hepatosomatic index (HSI) were measured in fish fed the HF diet. Compared to the fish fed HF diet, fish fed HL diets showed lower serum total triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatic malondialdehyde (MDA) and glycogen levels, and higher hepatic catalase (CAT) and glutathione peroxidase (GSH-PX) activities. In addition, the mRNA expression for lipolysis genes in fish liver were increased and for gluconeogenesis and fatty acid synthesis were reduced. The transcript levels of apoptosis-related genes were significantly down-regulated in the liver of largemouth bass in HL0.15 and HL0.20 groups compared to the HF group. Moreover, compared with the HF group, the mRNA expression of pro-inflammatory factors was significantly reduced in HL groups, and the histomorphology of the liver were significantly improved. These results suggested that LA supplementation in high-fat diets could improve lipid utilization, glycogen accumulation, antioxidant capacity of fish liver, thus reduce the adverse effects of high fat diets on fish, and then improve the growth performance of largemouth bass.

Enhancing renal protection against cadmium toxicity: the role of herbal active ingredients

Background

Rapid industrialization globally has led to a notable increase in the production and utilization of metals, including cadmium (Cd), consequently escalating global metal pollution worldwide. Cd, characterized as a persistent environmental contaminant, poses significant health risks, particularly impacting human health, notably the functionality of the kidneys. The profound effects of Cd stem primarily from its limited excretion capabilities and extended half-life within the human body. Mechanisms underlying its toxicity encompass generating reactive oxygen species (ROS), disrupting calcium-signaling pathways and impairing cellular antioxidant defense mechanisms. This review focuses on the protective effects of various herbal active ingredients against Cd-induced nephrotoxicity.

Aim

This study aims to investigate the mechanisms of action of herbal active ingredients, including ant-oxidative, anti-inflammatory and anti-apoptotic pathways, to elucidate potential therapeutic strategies for reducing nephrotoxicity caused by Cd exposure.

Methods

A comprehensive search of scientific databases, including Web of Science, PubMed, Scopus and Google Scholar, used relevant keywords to identify studies published up to October 2024.

Results

Research illustrates that herbal active ingredients protect against Cd nephrotoxicity by reducing oxidative stress, enhancing antioxidant enzyme activity, inhibiting inflammation, preventing apoptosis, alleviating endoplasmic reticulum (ER) stress, enhancing autophagy and improving mitochondrial function in the kidney.

Conclusion

The present study indicates that an extensive understanding of the protective effects of herbal active ingredients holds promise for the development of innovative approaches to safeguard human health and environmental integrity against the detrimental effects of Cd exposure.

Towards the Development of Novel, Point-of-Care Assays for Monitoring Different Forms of Antioxidant Activity: The RoXstaTM System

(1) Background: This study set out to develop a series of simple, novel, rapid methods for assessing different forms of antioxidant activity. (2) Methods: An ABTS platform was used to engineer: (i) an electrochemical post-activation assay to assess free radical scavenging activity; (ii) an electrochemical pre-activation strategy to assesses the suppression of free radical formation; (iii) a horseradish peroxidase-mediated oxidation system to monitor hydrogen peroxide scavenging activity and (iv) a cumene peroxide-hematin system to determine the ability of samples to scavenge the mixture of organic peroxides and peroxyl and alkoxyl radicals generated in the presence of these reagents. Each assay was assessed against a panel of candidate antioxidant compounds to determine their relative activities and specificities. In addition, human semen samples were analyzed to determine how the results of these antioxidant assays correlated with semen quality. (3) Results: All 4 assays revealed dose-dependent antioxidant activity on the part of vitamin C, N-acetyl cysteine, hypotaurine, BSA, melatonin, glutathione, resveratrol and epigallocatechin gallate. The other compounds tested either completely lacked antioxidant activity or were only active in one of the assays. Using unfractionated human semen as an exemplar of biological fluids rich in antioxidants, the outputs from the individual assays were found to reflect different aspects of semen quality. When the data from all 4 assays were combined, accurate predictions were generated reflecting the importance of oxidative stress in defining semen quality as reflected by sperm count, seminal lipid aldehyde content, sperm DNA damage and free radical generation by the sperm mitochondria. (4) Conclusions: The methodologies described in this paper constitute the basis for rapid, point-of-care assessments of oxidative stress.

The mode of toxic action of ionic liquids: Narrowing down possibilities using high-throughput, in vitro cell-based bioassays

Growing concerns about the environmental impact of ionic liquids (ILs) have spurred research into their (eco)toxic effects, but studies on their mode of toxic action (MOA) still remain limited. However, understanding the MOA and identifying structural features responsible for enhanced toxicity is crucial for characterising the hazard and designing safer alternatives. Therefore, 45 ILs, with systematically varied chemical structures, were tested for cytotoxicity and two specific endpoints in reporter gene assays targeting the Nrf2-ARE mediated oxidative stress response (AREc32) and aryl hydrocarbon receptor activation (AhR-CALUX). While none of the ILs activated the reporter genes, cytotoxicity was high and markedly different between cell lines. Seven and 25 ILs proved more cytotoxic than predicted by baseline toxicity model in the AREc32 and the AhR-CALUX assays, respectively. The length of the side chain and headgroup structures of ILs altered the MOA of ILs. Cellular metabolism of the ILs, investigated by LC-MS/MS, showed side-chain oxidation of the long-chain quaternary ammonium compounds in AhR-CALUX cells and, to a lower extent, in AREc32 cells, however, this transformation could not explain the high cytotoxicity. Effect data for 72 ILs for ten endpoints retrieved from the Tox21 database identified the inhibition of aromatase activity and of mitochondrial membrane potential as potential MOAs. However, in vitro fluorimetric assays for these endpoints demonstrated that effects were activated in a non-specific manner, probably through cytotoxicity. Although many of the ILs tested induced cytotoxicity at concentrations lower than baseline toxicity, the specific MOAs responsible could not be identified. Alternatively, we suggest that the descriptors currently used may fail to define the affinity of ILs for cells. Testing of the affinity of ILs for a diverse range of biomolecules is needed to accurately describe their interactions with cells.

Mapping of oxidative modifications on the alpha-keto glutarate dehydrogenase complex induced by singlet oxygen: Effects on structure and activity

The large multi-subunit mitochondrial alpha-keto glutarate dehydrogenase (KGDH) complex plays a key, rate-determining, role in the tricarboxylic acid (Krebs) cycle, catalyzing the conversion of alpha-keto glutarate to succinyl-CoA. This complex is both a source and target of oxidants, but the sites of modification and association with structural changes and activity loss are poorly understood. We report here oxidative modifications induced by Rose Bengal (RB) in the presence of O2, a source of singlet oxygen (1O2). A rapid loss of activity was detected, with this being dependent on light exposure, illumination time, and the presence of RB and O2. Activity loss was enhanced by D2O (consistent with 1O2 involvement), but diminished by both pre- and (to a lesser extent) post-illumination addition of lipoic acid and lipoamide. Aggregates containing all three KGDH subunits were detected on photooxidation. LC-MS experiments provided evidence for oxidation at 45 sites, including specific Met, His, Trp, Tyr residues and the lipoyllysine active-site cofactor. Products include mono- and di-oxygenated species, and kynurenine from Trp. Mapping of the modifications to the 3-D structure showed that these are localized to both the inner channel and the external surface, consistent with reactions of free 1O2, however the sites and extent of modification do not correlate with their solvent accessibility. These products are generated concurrently with loss of activity, indicative of strong links between these events. These data provide evidence for the impairment of KGDH activity by 1O2 via the oxidation of specific residues on the protein subunits of the complex.

Combination of High-Dose Parenteral Ascorbate (Vitamin C) and Alpha-Lipoic Acid Failed to Enhance Tumor-Inhibitory Effect But Increased Toxicity in Preclinical Cancer Models

Background

Intravenous vitamin C (IVC, ascorbate [Asc]) and alpha-lipoic acid (ALA) are frequently coadministered in integrative oncology clinics, with limited understanding of combination effects or drug-drug interactions. As high-dose IVC has anticancer activity through peroxide (H2O2), it is hypothesized that IV ALA, a thiol antioxidant, might have untoward effects when combined with IVC.

Methods

In vitro combination index (CI) was investigated in 6 types of human cancer cells, using clinically relevant concentrations of Asc (0.625-20 mM) and ALA (0.25, 0.5, and 1 mM) evaluated by nonconstant ratio metrics. Cellular H2O2 was measured using HeLa cells expressing a fluorescent probe HyPer. Mouse xenografts of the metastatic breast cancer MDA-MB-231 were treated with intraperitoneal injections of ALA (10, 20, and 50 mg/kg) and Asc (0.2, 0.5, and 4 g/kg) at various dose levels.

Results

Cancer cell lines were sensitive to Asc treatment but not to ALA. There is no evidence ALA becomes a prooxidant at higher doses. The CIs showed a mixture of synergistic and antagonistic effects with different ALA and Asc combination ratios, with a "U" shape response to Asc concentrations. The ALA concentrations did not influence the CIs or cellular H2O2 formation. Adding ALA to Asc dampened the increase of H2O2. Toxicity was observed in mice receiving prolonged treatment of ALA at all doses. The Asc at all doses was nontoxic. The combination of ALA and Asc increased toxicity. The ALA at all doses did not inhibit tumor growth. The Asc at 4 g/kg inhibited tumor growth. Adding ALA 50 mg/kg to Asc 4 g/kg did not enhance the effect, but lower doses of ALA (10 or 20 mg/kg) dampened the inhibitory effect of Asc.

Conclusions

These data do not support the concurrent or relative concurrent use of high-dose intravenous ALA with prooxidative high-dose IVC in clinical oncology care with potentially increased toxicity.

Alpha-Lipoic Acid: Biological Mechanisms and Health Benefits

Alpha-lipoic acid (ALA) is a bioactive molecule with significant health effects. The biological action of ALA has been ascribed to the characteristic antioxidant properties of the oxidized form (ALA) and its reduced counterpart the dihydrolipoic acid (DHLA) system. The ALA/DHLA combination represents an ideal antioxidant since it can quench radicals, is able to chelate metals, is amphiphilic, and has no major adverse effects. This unique system is able to scavenge reactive oxygen species, exerting a major effect on tissue levels of reduced forms of other antioxidants, including glutathione. For this reason, ALA is also known as the "antioxidant of antioxidants". This review analyzes the antioxidant, anti-inflammatory, and neuroprotective effects of ALA and discusses its applications as an ameliorative tool for chronic diseases and those associated with oxidative stress. Results from in vitro and in vivo studies demonstrated that ALA modulates various oxidative stress pathways suggesting its application, alone or in combination with other functional substances, as a useful support in numerous conditions, in which the balance oxidant-antioxidant is disrupted, such as neurodegenerative disorders. Based on several successful clinical studies, it has been also established that oral ALA supplements are clinically useful in relieving the complications of diabetes and other disorders including cardiovascular diseases and nerve discomforts suggesting that ALA can be considered a useful approach to improving our health.

Closed-loop recyclable polymers: from monomer and polymer design to the polymerization-depolymerization cycle

The extensive utilization of plastic, as a symbol of modern technological society, has consumed enormous amounts of finite and non-renewable fossil resources and produced huge amounts of plastic wastes in the land or ocean, and thus recycling and reuse of the plastic wastes have great ecological and economic benefits. Closed-loop recyclable polymers with inherent recyclability can be readily depolymerized into monomers with high selectivity and purity and repolymerized into polymers with the same performance. They are deemed to be the next generation of recyclable polymers and have captured great and increasing attention from academia and industry. Herein, we provide an overview of readily closed-loop recyclable polymers based on monomer and polymer design and no-other-reactant-involved reversible ring-opening and addition polymerization reactions. The state-of-the-art of circular polymers is separately summarized and discussed based on different monomers, including lactones, thiolactones, cyclic carbonates, hindered olefins, cycloolefins, thermally labile olefin comonomers, cyclic disulfides, cyclic (dithio) acetals, lactams, Diels-Alder addition monomers, Michael addition monomers, anhydride-secondary amide monomers, and cyclic anhydride-aldehyde monomers, and polymers with activatable end groups. The polymerization and depolymerization mechanisms are clearly disclosed, and the evolution of the monomer structure, the polymerization and depolymerization conditions, the corresponding polymerization yield, molecular weight, performance of the polymers, monomer recovery, and depolymerization equipment are also systematically summarized and discussed. Furthermore, the challenges and future prospects are also highlighted.

Exploration of dietary interventions to treat mitochondrial fatty acid disorders in a mouse model

Mitochondrial fatty acids synthesis (mtFAS) is a conserved metabolic pathway essential for mitochondrial respiration. The best characterized mtFAS product is the medium-chain fatty acid octanoate (C8) used as a substrate in the synthesis of lipoic acid (LA), a cofactor required by several mitochondrial enzyme complexes. In humans, mutations in the mtFAS component enoyl reductase MECR cause childhood-onset neurodegenerative disorder MEPAN. A complete deletion of Mecr in mice is embryonically lethal, while selective deletion of Mecr in cerebellar Purkinje cells causes neurodegeneration in these cells. A fundamental question in the research of mtFAS deficiency is if the defect is amenable to treatment by supplementation with known mtFAS products. Here we used the Purkinje-cell specific mtFAS deficiency neurodegeneration model mice to study if feeding the mice with a medium-chain triacylglycerol-rich formula supplemented with LA could slow down or prevent the neurodegeneration in Purkinje cell-specific Mecr KO mice. Feeding started at the age of 4 weeks and continued until the age of 9 months. The neurological status on the mice was assessed at the age of 3, 6, and 9 months with behavioral tests and the state of the Purkinje cell deterioration in the cerebellum was studied histologically. We showed that feeding the mice with medium chain triacylglycerols and LA affected fatty acid profiles in the cerebellum and plasma but did not prevent the development of neurodegeneration in these mice. Our results indicate that dietary supplementation with medium chain fatty acids and LA alone is not an efficient way to treat mtFAS disorders.

The Multifaceted Role of Alpha-Lipoic Acid in Cancer Prevention, Occurrence, and Treatment

Alpha-lipoic acid (ALA) is a naturally occurring compound synthesized by mitochondria and widely distributed in both animal and plant tissues. It primarily influences cellular metabolism and oxidative stress networks through its antioxidant properties and is an important drug for treating metabolic diseases associated with oxidative damage. Nevertheless, research indicates that the mechanism by which ALA affects cancer cells is distinct from that observed in normal cells, exhibiting pro-oxidative properties. Therefore, this review aims to describe the main chemical and biological functions of ALA in the cancer environment, including its mechanisms and effects in tumor prevention and anticancer activity, as well as its role as an adjunctive drug in cancer therapy. We specifically focus on the interactions between ALA and various carcinogenic and anti-carcinogenic pathways and discuss ALA's pro-oxidative capabilities in the unique redox environment of cancer cells. Additionally, we elaborate on ALA's roles in nanomedicine, hypoxia-inducible factors, and cancer stem cell research, proposing hypotheses and potential explanations for currently unresolved issues.

Protective effects of the R-(+)-thioctic acid treatment: possible anti-inflammatory activity on heart of hypertensive rats

BACKGROUND

In cardiovascular disease, high blood pressure is associated with oxidative stress, promoting endothelial dysfunction, vascular remodeling, and inflammation. Clinical trials are discordant that the most effective treatment in the management of hypertension seems to be the administration of anti-hypertensive drugs with antioxidant properties. The study aims to evaluate the effects of the eutomer of thioctic acid on oxidative stress and inflammation in the heart of spontaneously hypertensive rats compared to normotensive Wistar Kyoto rats.

METHODS

To study the oxidative status, the malondialdehyde and 4-hydroxynonenal concentration, protein oxidation were measured in the heart. Morphological analysis were performed. Immunohistochemistry and Western blot were done for alpha-smooth muscle actin and transforming growth factor beta to assess fibrosis; cytokines and nuclear factor kappaB to assess inflammatory processes.

RESULTS

Spontaneously hypertensive rats were characterized by hypertension with increased malondialdehyde levels in the heart. OxyBlot in the heart of spontaneously hypertensive rats showed an increase in proteins' oxidative status. Cardiomyocyte hypertrophy and fibrosis in the ventricles were associated with an increased expression of alpha-smooth muscle actin and pro-inflammatory cytokines, reduced by the eutomer of thioctic acid supplementation.

CONCLUSIONS

Based on this evidence, eutomer of thioctic acid could represent an appropriate antioxidant molecule to reduce oxidative stress and prevent inflammatory processes on the cardiomyocytes and cardiac vascular endothelium.

Passerini polymerization of α-lipoic acid for dynamically crosslinking 1,2-dithiolane-functionalized polymers

Passerini polymerization using naturally occurring α-lipoic acid as a raw material yields polyamides with 1,2-dithiolane functional groups in a one-step reaction. The polyamide exhibits characteristics of an adaptable dynamically crosslinked network through reversible ring-opening reaction of 1,2-dithiolane, enabling self-healing, reusable strong adhesion, and regeneration through decrosslinking and re-crosslinking.

Golgi apparatus-targeting fluorescent probe for the imaging of superoxide anion (O2•-) in living cells during ferroptosis

Ferroptosis is an emerging iron-dependent oxidative cell death type, and recently has been demonstrated to show close relation with Golgi apparatus (GA). Exploring the fluctuation of superoxide anion (O2•-) level in GA during ferroptosis is of great significance to profoundly study the biological functions of GA in ferroptosis. Here, we present a GA-targeting probe (N-GA) to monitor cellular O2•- during ferroptosis. N-GA employed a triflate group and a tetradecanoic amide unit as the recognition site for O2•- and GA-targeting unit, respectively. After the response of N-GA to O2•-, the triflate unit of N-GA converted into hydroxyl group with strong electron-donating ability, generating bright green fluorescence under UV light. N-GA exhibited excellent sensitivity and selectivity towards O2•-. Fluorescence imaging results showed that N-GA could be applied as a GA-targeting probe to monitor cellular O2•-. The stimulation of cells with PMA and rotenone could result in the massive generation of endogenous O2•- in GA. Erastin-induced ferroptosis can markedly induce the increase of O2•- level in GA. Similar to Fer-1 and DFO, dihydrolipoic acid (DHLA) and rutin were demonstrated to inhibit the enormous production of O2•- in GA of the living cells during ferroptosis.

Effectiveness of Vitamin D and Alpha-Lipoic Acid in COVID-19 Infection: A Literature Review

Over three years since the World Health Organization (WHO) declared COVID-19 a pandemic, it is still a global burden. Vaccines against COVID-19, caused by SARS-CoV-2, are available and effective for preventing disease. However, their protective effects are not 100%. Currently, the U.S. Food and Drug Administration (FDA) has only approved a limited number of inpatient treatments for COVID-19, such as remdesivir, baricitinib, and tocilizumab. These medications have indications and contraindications applicable to a select patient population. Finding additional effective therapies that are widely available with limited risk could be vital in optimizing treatment strategies for this viral illness. Some vitamins and supplements have been identified as potential options for managing COVID-19. Vitamin D (VD) deficiency has been associated with respiratory tract infections. Moreover, alpha-lipoic acid (ALA) is a powerful antioxidant and helps reduce inflammatory responses in many pathologic conditions. This review aims to analyze the current evidence regarding the effectiveness of VD and alpha-lipoic acid in COVID-19 infection in both outpatient and hospitalized patients. Relevant randomized controlled trials (RCTs) were identified via the PubMed database from January 1, 2021, to December 31, 2023. Inclusion criteria were as follows: the study design was a randomized controlled trial (RCT), the usage of a constant dose during the intervention period without any additional boluses, and a research ethics committee approved it. Exclusion criteria included a lack of an outcome or apparent intervention, additional boluses, or a single-dose regimen in all the interventional groups. There were 11 studies with a total sample size of 35,717 patients that met the criteria for this review. A total of 10 RCTs examined the efficacy of VD, and one RCT that reviewed the efficacy of ALA was identified. All of the articles investigated the use of VD or ALA during the treatment of COVID-19. The endpoints of each study varied, including length of stay in hospital, viral load, SARS-CoV-2 infection rate, mechanical ventilation, inflammatory markers, clinical symptoms, Sequential Organ Failure Assessment (SOFA) score, and mortality. In 8/10 VD supplementation trials, significant differences were identified between the interventional and placebo groups in the aforementioned parameters. In 2/10 VD supplementation trials, no significant differences were identified. The ALA supplementation RCT found no differences between the interventional and placebo groups in the SOFA score and 30-day all-cause mortality rate. The current literature suggests that VD can potentially reduce the SARS-CoV-2 infection rate, oxygen requirements, inflammatory markers, clinical symptoms, and mortality. Regarding ALA, although there was a suggestion of benefit, it was not statistically significant. Common limitations among the different studies included relatively small sample sizes, different geographical patient locations among studies, and differences in dosages. Trials investigating the effects of higher doses of VD supplementation on SARS-CoV-2 infection should be conducted. More research is needed to define best practices and optimal dosing protocols for the use of VD in COVID-19.

Alpha-lipoic acid (ALA) ameliorates early brain injury after subarachnoid hemorrhage in Sprague-Dawley (SD) rats via inhibiting STING-NLRP3 inflammatory signaling

Neuroinflammation is intimately associated with poor prognosis in patients with subarachnoid hemorrhage (SAH). Alpha-lipoic acid (ALA), a disulfide antioxidant, has been shown to be neuroprotective in an in vivo model of neurological injury; however, the role of ALA in SAH has never been evaluated. In this study, the Sprague-Dawley rats SAH model was induced by endovascular perforation method. ALA was transplanted intravenously into rats, and SR-717, a stimulator of interferon genes (STING) agonist, was injected intraperitoneally. The effects of ALA on early brain injury were assayed by neurological score, hematoxylin and eosin staining and Nissl staining. Immunohistochemistry staining and Western blotting were used to analyze various proteins. ALA significantly reduced STING- NLRP3 protein expression and decreased cell death, which in turn mitigated the neurobehavioral dysfunction following SAH. Furthermore, coadministration of ALA and SR-717 promoted STING-NLRP3 signaling pathway activation following SAH, which reversed the inhibitory effect of ALA on STING-NLRP3 protein activation and increased the neurological deficits. In conclusion, ALA may be a promising therapeutic strategy for alleviating early brain injury after SAH.

Innovative drug delivery strategies to the CNS for the treatment of multiple sclerosis

Disorders of the central nervous system (CNS), such as multiple sclerosis (MS) represent a great emotional, financial and social burden. Despite intense efforts, great unmet medical needs remain in that field. MS is an autoimmune, chronic inflammatory demyelinating disease with no curative treatment up to date. The current therapies mostly act in the periphery and seek to modulate aberrant immune responses as well as slow down the progression of the disease. Some of these therapies are associated with adverse effects related partly to their administration route and show some limitations due to their rapid clearance and inability to reach the CNS. The scientific community have recently focused their research on developing MS therapies targeting different processes within the CNS. However, delivery of therapeutics to the CNS is mainly limited by the presence of the blood-brain barrier (BBB). Therefore, there is a pressing need to develop new drug delivery strategies that ensure CNS availability to capitalize on identified therapeutic targets. Several approaches have been developed to overcome or bypass the BBB and increase delivery of therapeutics to the CNS. Among these strategies, the use of alternative routes of administration, such as the nose-to-brain (N2B) pathway, offers a promising non-invasive option in the scope of MS, as it would allow a direct transport of the drugs from the nasal cavity to the brain. Moreover, the combination of bioactive molecules within nanocarriers bring forth new opportunities for MS therapies, allowing and/or increasing their transport to the CNS. Here we will review and discuss these alternative administration routes as well as the nanocarrier approaches useful to deliver drugs for MS.

α-lipoic acid ameliorates hepatotoxicity induced by chronic ammonia toxicity in crucian carp (Carassius auratus gibelio) by alleviating oxidative stress, inflammation and inhibiting ERS pathway

High environment ammonia (HEA) poses a deadly threat to aquatic animals and indirectly impacts human healthy life, while nutritional regulation can alleviate chronic ammonia toxicity. α-lipoic acid exhibits antioxidative effects in both aqueous and lipid environments, mitigating cellular and tissue damage caused by oxidative stress by aiding in the neutralization of free radicals (reactive oxygen species). Hence, investigating its potential as an effective antioxidant and its protective mechanisms against chronic ammonia stress in crucian carp is highly valuable. Experimental fish (initial weight 20.47 ± 1.68 g) were fed diets supplemented with or without 0.1% α-lipoic acid followed by a chronic ammonia exposure (10 mg/L) for 42 days. The results revealed that chronic ammonia stress affected growth (weight gain rate, specific growth rate, and feed conversion rate), leading to oxidative stress (decreased the activities of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase; decreased total antioxidant capacity), increased lipid peroxidation (accumulation of malondialdehyde), immune suppression (decreased contents of nonspecific immune enzymes AKP and ACP, 50% hemolytic complement, and decrease of immunoglobulin M), impaired ammonia metabolism (reduced contents of Glu, GS, GSH, and Gln), imbalance of expression of induced antioxidant-related genes (downregulation of Cu/Zu SOD, CAT, Nrf2, and HO-1; upregulation of GST and Keap1), induction of pro-apoptotic molecules (transcription of BAX, Caspase3, and Caspase9), downregulation of anti-apoptotic gene Bcl-2 expression, and induction of endoplasmic reticulum stress (upregulation of IRE1, PERK, and ATF6 expression). The results suggested that the supplementation of α-lipoic acid could effectively induce humoral immunity, alleviate oxidative stress injury and endoplasmic reticulum stress, and ultimately alleviate liver injury induced by ammonia poisoning (50-60% reduction). This provides theoretical basis for revealing the toxicity of long-term ammonia stress and provides new insights into the anti-ammonia toxicity mechanism of α-lipoic acid.

Effect of Tea Polyphenols, α-Lipoic Acid and Their Joint Use on the Antioxidant and Lipid Metabolism Performance of Hybrid Grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) Fed with High-Lipid Diets

This study investigated tea polyphenols (TP), α-lipoic acid (ALA) and their joint use on the antioxidant and lipid metabolic performance of hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) took food with high-fat diets. Six high-lipid diets with isonitrogen (50% of dry matter) and isolipid (17% of dry value) were designed, in which a total content of 1,000 mg/kg additives were added to each group except for the control group (FL). The additives addition ratios in each group were ALA (AL), TP (PL), ALA : TP = 1 : 1 (EL), ALA : TP = 1 : 2 (OL), ALA : TP = 2 : 1 (TL). Each diet was divided into three repeat groups with 30 tails (6.84 ± 0.01 g) in each group and fed for 8 weeks. The consequences were as follows: (1) the highest weight gain rate, specific growth rate, as well as the lowest feed conversion ratio and ingestion rate were discovered in the OL team, which were opposite to the TL group. (2) The body fat content and muscle fat content in the fish oil group were the lowest (P < 0.05), while those of the TL group were the highest. (3) Serum catalase, glutathione peroxidase, total antioxidant capacity, and superoxide dismutase activities were the highest, and the content of reactive oxygen species was the lowest in the OL group. (4) The OL group has the highest hepatic lipase activity and the lowest very low-density lipoprotein content of the liver. In contrast, the TL group had the highest fatty acid synthetase (FAS) activity (P < 0.05). (5) The oil-red aspects of liver tissue displayed lipid particles in other groups were reduced to different degrees compared with FL group, and the OL group showed the best lipid-lowering effect. (6) Compared with the FL group, the relative expressions of FAS, acetyl-CoA carboxylase (acc), and apolipoprotein b-100 (apoB100) genes in the liver were decreased. The relative expressions of lipoprotein lipase (lpl) and peroxisome proliferators-activated receptors-α (pparα) genes related to lipid catabolism were increased, among which the OL group had the most significant change (P < 0.05). (7) According to the 7-day challenge test of Vibrio alginolyticus, the OL group had the highest survival rate. To sum up, both ALA and TP have positive effects on relieving the lipid metabolism disorder of hybrid grouper. If they are jointly used, adding ALA : TP in a ratio of 1 : 2 (OL) may have the best effect, and an addition ratio of 2 : 1 (TL) may inhibit the hybrid grouper growth and increase the feeding cost.

Pathogenesis of Alzheimer's Disease and Diversity of 1,2,3-Triazole Scaffold in Drug Development: Design Strategies, Structural Insights, and Therapeutic Potential

Alzheimer's disease is a most prevalent form of dementia all around the globe and currently poses a significant challenge to the healthcare system. Currently available drugs only slow the progression of this disease rather than provide proper containment. Identification of multiple targets responsible for this disease in the last three decades established it as a multifactorial neurodegenerative disorder that needs novel multifunctional agents for its management and the possible reason for the failure of currently available single target clinical drugs. 1,2,3-Triazole is a miraculous nucleus in medicinal chemistry and the first choice for development of multifunctional hybrid molecules. Apart from that, it is an integral component of various drugs in clinical trials as well as in clinical practice. This review is focused on the pathogenesis of Alzheimer's disease and 1,2,3-triazole containing derivatives developed in recent decades as potential anti-Alzheimer's agents. The review will provide (A) precise insight of various established targets of Alzheimer's disease including cholinergic, amyloid, tau, monoamine oxidases, glutamate, calcium, and reactive oxygen species hypothesis and (B) design hypothesis, structure-activity relationships, and pharmacological outcomes of 1,2,3-triazole containing multifunctional anti-Alzheimer's agents. This review will provide a baseline for various research groups working on Alzheimer's drug development in designing potent, safer, and effective multifunctional anti-Alzheimer's candidates of the future.

Antioxidant Nutraceutical Strategies in the Prevention of Oxidative Stress Related Eye Diseases

This review aims to discuss the delicate balance between the physiological production of reactive oxygen species and the role of antioxidant nutraceutical molecules in managing radicals in the complex anatomical structure of the eye. Many molecules and enzymes with reducing and antioxidant potential are present in different parts of the eye. Some of these, such as glutathione, N-acetylcysteine, α-lipoic acid, coenzyme Q10, and enzymatic antioxidants, are endogenously produced by the body. Others, such as plant-derived polyphenols and carotenoids, vitamins B2, C, and E, zinc and selenium, and omega-3 polyunsaturated fatty acids, must be obtained through the diet and are considered essential nutrients. When the equilibrium between the production of reactive oxygen species and their scavenging is disrupted, radical generation overwhelms the endogenous antioxidant arsenal, leading to oxidative stress-related eye disorders and aging. Therefore, the roles of antioxidants contained in dietary supplements in preventing oxidative stress-based ocular dysfunctions are also discussed. However, the results of studies investigating the efficacy of antioxidant supplementation have been mixed or inconclusive, indicating a need for future research to highlight the potential of antioxidant molecules and to develop new preventive nutritional strategies.

The effect of a-Lipoic acid (ALA) on oxidative stress, inflammation, and apoptosis in high glucose-induced human corneal epithelial cells

PURPOSE

Oxidative stress and inflammation had been proved to play important role in the progression of diabetic keratopathy (DK). The excessive accumulation of AGEs and their bond to AGE receptor (RAGE) in corneas that cause the formation of oxygen radicals and the release of inflammatory cytokines, induce cell apoptosis. Our current study was aimed to evaluate the effect of ALA on AGEs accumulation as well as to study the molecular mechanism of ALA against AGE-RAGE axis mediated oxidative stress, apoptosis, and inflammation in HG-induced HCECs, so as to provide cytological basis for the treatment of DK.

METHODS

HCECs were cultured in a variety concentration of glucose medium (5.5, 10, 25, 30, 40, and 50 mM) for 48 h. The cell proliferation was evaluated by CCK-8 assay. Apoptosis was investigated with the Annexin V- fluorescein isothiocyanate (V-FITC)/PI kit, while, the apoptotic cells were determined by flow cytometer and TUNEL cells apoptosis Kit. According to the results of cell proliferation and cell apoptosis, 25 mM glucose medium was used in the following HG experiment. The effect of ALA on HG-induced HCECs was evaluated. The HCECs were treated with 5.5 mM glucose (normal glucose group, NG group), 5.5 mM glucose + 22.5 mM mannitol (osmotic pressure control group, OP group), 25 mM glucose (high glucose group, HG group) and 25 mM glucose + ALA (HG + ALA group) for 24 and 48 h. The accumulation of intracellular AGEs was detected by ELISA kit. The RAGE, catalase (CAT), superoxide dismutase 2 (SOD2), cleaved cysteine-aspartic acid protease-3 (Cleaved caspase-3), Toll-like receptors 4 (TLR4), Nod-like receptor protein 3 (NLRP3) inflammasome, interleukin 1 beta (IL-1 ß), and interleukin 18 (IL-18) were quantified by RT-PCR, Western blotting, and Immunofluorescence, respectively. Reactive oxygen species (ROS) production was evaluated by fluorescence microscope and fluorescence microplate reader.

RESULTS

When the glucose medium was higher than 25 mM, cell proliferation was significantly inhibited and apoptosis ratio was increased (P < 0.001). In HG environment, ALA treatment alleviated the inhibition of HCECs in a dose-dependent manner, 25 μM ALA was the minimum effective dose. ALA could significantly reduce the intracellular accumulation of AGEs (P < 0.001), activate protein and genes expression of CAT and SOD2 (P < 0.001), and therefore inhibited ROS-induced oxidative stress and cells apoptosis. Besides, ALA could effectively down-regulate the protein and gene level of RAGE, TLR4, NLRP3, IL-1B, IL-18 (P < 0.05), and therefore alleviated AGEs-RAGE-TLR4-NLRP3 pathway-induced inflammation in HG-induced HCECs.

CONCLUSION

Our study indicated that ALA could be a desired treatment for DK due to its potential capacity of reducing accumulation of advanced glycation end products (AGEs) and down-regulating AGE-RAGE axis-mediated oxidative stress, cell apoptosis, and inflammation in high glucose (HG)-induced human corneal epithelial cells (HCECs), which may provide cytological basis for therapeutic targets that are ultimately of clinical benefit.

Cognitive and Mood Effect of Alpha-Lipoic Acid Supplementation in a Nonclinical Elder Sample: An Open-Label Pilot Study

BACKGROUND

Memory disorders are common among elder people, and nonclinical cognitive decline is commonly experienced with age. Preclinical investigations have explored the possible role of alpha-lipoic acid (ALA), a known antioxidant compound abundant in vegetables and animal tissues, in reducing oxidative stress in the aging brain and preventing cognitive decline. However, clinical evidence is limited, and the few existing results are contrasting. In addition, while most of the existing trials have been focused on the effects of ALA administration in Alzheimer's disease (AD) or other types of dementia, studies evaluating its effects on nonclinical elder population are still missing.

METHODS

In the present open-label, pilot study, fifteen elder patients (mean age: 84.5 ± 5.77) received ALA at a daily dose of 600 mg/day for 12 weeks. General cognitive function, executive function, and mood symptom assessment were carried out at baseline and at the endpoint.

RESULTS

Overall, ALA administration was generally well-tolerated (only one dropout due to gastrointestinal side effects). However, no statistically significant effects either on cognitive function, executive function, or mood were found.

CONCLUSIONS

Despite several limitations, our study found no evidence of positive effects on cognition and mood after ALA administration in elder people without the diagnosis of AD or cognitive impairment. Further clinical trials are needed to better investigate ALA effectiveness on cognition and mood in elder subjects.

The effect of alpha-lipoic acid on sperm functions in rodent models for male infertility: A systematic review

In this systematic review, we assessed different studies to evaluate the protective effect of alpha-lipoic acid (ALA), as a multifaceted antioxidant, on sperm functions in rodent models. Four databases were searched to find papers reporting the effect of ALA treatment on animal models of male infertility. Up to December 2022, 11,787 articles were identified to explain the ALA protective effects. The included studies were evaluated for eligibility and risk of bias (CRD42022341370). Finally, we identified 23 studies that explain the effect of ALA on sperm functions in rodents. Among them, 15 studies indicated that ALA could restore sperm parameters. Six studies showed a significant reduction in sperm DNA damage by ALA treatment. Seventeen papers displayed the ALA antioxidant ability, and four studies indicated the ALA anti-inflammatory effect. Besides, thirteen studies displayed that ALA could modulate androgenesis. Also, eighteen studies revealed that ALA restored the testicular architecture to normal, and was also effective in restoring reproductive performance in two included studies. This systematic review provided cogent evidence for the protective effect of ALA in rodent models for male infertility by re-establishing spermatogenesis and steroidogenesis and maintaining redox and immune systems homeostasis.

Effects of alpha lipoic acid treatment during in vitro maturation on the development of porcine somatic cell nuclear transfer embryos

Oxidative stress influences the embryo production efficiency in vitro. We investigated the effects of alpha lipoic acid (ALA) treatment during the in vitro maturation (IVM) period on the porcine somatic cell nuclear transfer (SCNT) embryo production. After IVM, maturation rates of the 12.5- and 25-μM ALA-treated groups were not significantly different from those of the 0-μM ALA-treated group. Compared to those in the 0-μM ALA-treated group, the reactive oxygen species and glutathione levels were significantly decreased and increased, respectively, in the cytoplasm of matured oocytes in the 12.5-50-μM ALA-treated groups. Apoptosis rate in cumulus cells after IVM was significantly lower in the 12.5-50-μM ALA-treated groups than in the 0-μM ALA-treated group. Blastocyst formation rate was significantly higher in parthenogenetic oocytes treated with 12.5-μM ALA than in the 0-, 25-, and 50-μM ALA-treated groups. Similarly, in SCNT embryos, the 12.5-μM ALA-treated group showed a significantly higher blastocyst formation rate than the 0-μM ALA-treated group. Apoptosis rate in SCNT blastocysts was significantly decreased by 12.5-μM ALA treatment. The results showed that treatment with 12.5-μM ALA during IVM improves porcine SCNT embryo development and partial quality.

SARS-CoV-2 Infection Dysregulates Host Iron (Fe)-Redox Homeostasis (Fe-R-H): Role of Fe-Redox Regulators, Ferroptosis Inhibitors, Anticoagulants, and Iron-Chelators in COVID-19 Control

Severe imbalance in iron metabolism among SARS-CoV-2 infected patients is prominent in every symptomatic (mild, moderate to severe) clinical phase of COVID-19. Phase-I - Hypoxia correlates with reduced O₂ transport by erythrocytes, overexpression of HIF-1α, altered mitochondrial bioenergetics with host metabolic reprogramming (HMR). Phase-II - Hyperferritinemia results from an increased iron overload, which triggers a fulminant proinflammatory response - the acute cytokine release syndrome (CRS). Elevated cytokine levels (i.e. IL6, TNFα and CRP) strongly correlates with altered ferritin/TF ratios in COVID-19 patients. Phase-III - Thromboembolism is consequential to erythrocyte dysfunction with heme release, increased prothrombin time and elevated D-dimers, cumulatively linked to severe coagulopathies with life-threatening outcomes such as ARDS, and multi-organ failure. Taken together, Fe-R-H dysregulation is implicated in every symptomatic phase of COVID-19. Fe-R-H regulators such as lactoferrin (LF), hemoxygenase-1 (HO-1), erythropoietin (EPO) and hepcidin modulators are innate bio-replenishments that sequester iron, neutralize iron-mediated free radicals, reduce oxidative stress, and improve host defense by optimizing iron metabolism. Due to its pivotal role in 'cytokine storm', ferroptosis is a potential intervention target. Ferroptosis inhibitors such as ferrostatin-1, liproxstatin-1, quercetin, and melatonin could prevent mitochondrial lipid peroxidation, up-regulate antioxidant/GSH levels and abrogate iron overload-induced apoptosis through activation of Nrf2 and HO-1 signaling pathways. Iron chelators such as heparin, deferoxamine, caffeic acid, curcumin, α-lipoic acid, and phytic acid could protect against ferroptosis and restore mitochondrial function, iron-redox potential, and rebalance Fe-R-H status. Therefore, Fe-R-H restoration is a host biomarker-driven potential combat strategy for an effective clinical and post-recovery management of COVID-19.

Alpha-Lipoic Acid and Glucose Metabolism: A Comprehensive Update on Biochemical and Therapeutic Features

Alpha-lipoic acid (ALA) is a natural compound with antioxidant and pro-oxidant properties which has effects on the regulation of insulin sensitivity and insulin secretion. ALA is widely prescribed in patients with diabetic polyneuropathy due to its positive effects on nerve conduction and alleviation of symptoms. It is, moreover, also prescribed in other insulin resistance conditions such as metabolic syndrome (SM), polycystic ovary syndrome (PCOS) and obesity. However, several cases of Insulin Autoimmune Syndrome (IAS) have been reported in subjects taking ALA. The aim of the present review is to describe the main chemical and biological functions of ALA in glucose metabolism, focusing on its antioxidant activity, its role in modulating insulin sensitivity and secretion and in symptomatic peripheral diabetic polyneuropathy. We also provide a potential explanation for increased risk for the development of IAS.

Alpha-Lipoic Acid as an Antioxidant Strategy for Managing Neuropathic Pain

Neuropathic pain (NP) is the most prevalent and debilitating form of chronic pain, caused by injuries or diseases of the somatosensory system. Since current first-line treatments only provide poor symptomatic relief, the search for new therapeutic strategies for managing NP is an active field of investigation. Multiple mechanisms contribute to the genesis and maintenance of NP, including damage caused by oxidative stress. The naturally occurring antioxidant alpha-lipoic acid (ALA) is a promising therapeutic agent for the management of NP. Several pre-clinical in vitro and in vivo studies as well as clinical trials demonstrate the analgesic potential of ALA in the management of NP. The beneficial biological activities of ALA are reflected in the various patents for the development of ALA-based innovative products. This review demonstrates the therapeutic potential of ALA in the management of NP by discussing its analgesic effects by multiple antioxidant mechanisms as well as the use of patented ALA-based products and how technological approaches have been applied to enhance ALA's pharmacological properties.

The effects of alpha-lipoic acid (ALA) on the urinary bladder injury in rats exposed to chronic stress: A histochemical study

Objective: In the present study, we aimed to investigate the morphological and biochemical effects of alpha-lipoic acid (ALA) on bladder injury caused by water avoidance stress (WAS) and to show its effect on the number of degranulated mast cells, which increase after stress. Materials and Methods: Wistar albino rats were subjected to WAS and the animals in the treatment group were injected ALA. After the urinary bladder tissues were subjected to routine tissue processing, hematoxylin-eosin staining and periodic acid-Schiff reaction were applied to observe general morphology and acidic toluidine blue method to investigate mast cells. Biochemical assessments of malondialdehyde (MDA) and glutathione (GSH) were also obtained. Transmission electron microscope was used for the ultrastructural, and scanning electron microscope for the topographical analyses. Results: The experiments showed that chronic stress caused injury in the bladder, increased degranulated and total number of mast cells and decreased GSH and increased MDA levels. ALA treatment after WAS ameliorated bladder injury in most areas, decreased degranulated and total mast cell number and increased GSH and decreased MDA levels. Conclusion: It was concluded that ALA can be a useful agent in the treatment of interstitial cystitis.

Dietary Antioxidant-Constructed Nanodrugs Can High-Efficiently Kill Cancer Cells while Protecting Noncancer Cells

Despite great advances, the development of cancer drugs that can efficiently kill cancer cells while protecting noncancer cells has not been achieved. By using only dietary antioxidants vitamin C (VC) and (R)-(+)-lipoic acid (LA), we herein develop a nanodrug VC@cLAV featuring the above function. After entering cells, cLAV dissociates into LA and DHLA (dihydrolipoic acid, reduced form of LA) and releases VC and DHA (dehydroascorbate, oxidized form of VC). In cancer cells, the two redox pairs recycle each other and dramatically promote the intracellular reactive oxygen species production to kill cancer cells at low doses comparable to cytotoxic drugs. Oppositely in noncancer cells, the LA/DHLA and VC/DHA pairs exert anti-oxidant action to actively protect the organism by preventing the normal cells from oxidative stress and repairing cells suffering from oxidative stress. When compared with the first-line cytotoxic drug, VC@cLAV displayed superior therapeutic outcomes yet without side effects in diverse tumor models including patient-derived xenograft (PDX). This drug with efficient cancer cell killing and noncancer cell protection represents a new cancer therapy.

Oxoplatin-Based Pt(IV) Lipoate Complexes and Their Biological Activity

α-Lipoic acid, known for its anti-inflammatory and antioxidant activity, represents a promising ligand for Pt(IV) prodrugs. Three new Pt(IV) lipoate complexes were synthesized and characterized by NMR spectroscopy (1 H, 13 C, 195 Pt), mass spectrometry and elemental analysis. Due to the low solubility of the complex containing two axial lipoate ligands, further experiments to examine the biological activity were performed with two Pt(IV) complexes containing just one axial lipoate ligand. Both complexes exhibit anticancer activity and produce reactive oxygen species (ROS) in the cell lines tested. Especially, the monosubstituted complex can be reduced by ascorbic acid and forms adducts with 9-methylguanine (9MeG), which is favorable for the formation of DNA-crosslinks in the cells.

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.

Neuroprotective Role of α-Lipoic Acid in Iron-Overload-Mediated Toxicity and Inflammation in In Vitro and In Vivo Models

Hemoglobin and iron overload is considered the major contributor to intracerebral hemorrhage (ICH)-induced brain injury. Accumulation of iron in the brain leads to microglia activation, inflammation and cell loss. Current available treatments for iron overload-mediated disorders are characterized by severe adverse effects, making such conditions an unmet clinical need. We assessed the potential of α-lipoic acid (ALA) as an iron chelator, antioxidant and anti-inflammatory agent in both in vitro and in vivo models of iron overload. ALA was found to revert iron-overload-induced toxicity in HMC3 microglia cell line, preventing cell apoptosis, reactive oxygen species generation and reducing glutathione depletion. Furthermore, ALA regulated gene expression of iron-related markers and inflammatory cytokines, such as IL-6, IL-1β and TNF. Iron toxicity also affects mitochondria fitness and biogenesis, impairments which were prevented by ALA pre-treatment in vitro. Immunocytochemistry assay showed that, although iron treatment caused inflammatory activation of microglia, ALA treatment resulted in increased ARG1 expression, suggesting it promoted an anti-inflammatory phenotype. We also assessed the effects of ALA in an in vivo zebrafish model of iron overload, showing that ALA treatment was able to reduce iron accumulation in the brain and reduced iron-mediated oxidative stress and inflammation. Our data support ALA as a novel approach for iron-overload-induced brain damage.

The Protective Effect of α-Lipoic Acid against Gold Nanoparticles (AuNPs)-Mediated Liver Damage Is Associated with Upregulating Nrf2 and Suppressing NF-κB

This study examined if regulating the keap-1? Nrf2 antioxidant pathway mediated gold nanoparticles (AuNPs) induced liver damage, and examined the protective effect of co-supplement of α-lipoic acid (α-LA). Rats were separated into 4 groups (n = 8/each) as control, α-LA (200 mg/kg), AuNPs (5 µg/2.85 × 10¹¹), and AuNPs (5 µg/2.85 × 10¹¹) + α-LA (200 mg/kg). After 7 days, AuNPs induced severe degeneration in the livers of rats with the appearance of some fatty changes. In addition, it increased serum levels of alanine aminotransferase (ALT) and gamma-glutamyl transferase (ɣ-GTT), and aspartate aminotransferase (AST), as well as liver levels of malondialdehyde (MDA). Concomitantly, AuNPs significantly depleted hepatic levels of total glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) but increased hepatic levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). It also reduced mRNA levels of B-cell lymphoma 2 (Bcl2) and heme oxygenase-1 (HO-1) but significantly increased those of Bax and cleaved caspase-3, as well as the ratio of Bax/Bcl2. In addition, AuNPs enhanced the total and nuclear levels of NF-κB p65 but reduced the mRNA and total and nuclear protein levels of Nrf2. Of note, AuNPs did not affect the mRNA levels of keap-1. All these events were reversed by α-LA in the AuNPs-treated rats. In conclusion, α-LA attenuated AuNPs-mediated liver damage in rats by suppressing oxidative stress and inflammation, effects that are associated with upregulation/activation of Nrf2.

Dietary α-lipoic acid alleviates deltamethrin-induced immunosuppression and oxidative stress in northern snakehead (Channa argus) via Nrf2/NF-κB signaling pathway

The goal of the study was to determine the ameliorative effects of dietary alpha-lipoic acid (α-LA) on deltamethrin (DEL)-induced immunosuppression and oxidative stress in northern snakehead (Channa argus). The northern snakeheads (15.38 ± 0.09 g) were exposed to DEL (0.242 μg/L) and fed with diets supplemented α-LA at 300, 600, and 900 mg/kg. After the 28-day exposure test, we obtained the following results: i) α-LA alleviates DEL-induced liver injury by reversing the increase of the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and liver cytochrome P450 enzymes (Cytochrome P450 (cyp)1a and cyp1b) expression levels. ii) α-LA can reverse the DEL-induced reduction of serum complement 4 (C4), C3, immunoglobulin M (IgM), and lysozyme (LYS) levels and the increase of liver and intestine nuclear factor kappa B (nf-κb) p65, tumor necrosis factor (tnf)-α, interleukin (il)-1β, il-8, and il-6 gene expressions, while il-10 expression levels showed the opposite result. iii) α-LA reversed the reduction of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px) levels in the liver and intestine induced by DEL, while malondialdehyde (MDA) showed the opposite result. iv) α-LA reversed the reduction of Cu/Zn sod, nuclear factor erythroid 2-related factor 2 (nrf2), NAD (P)H: quinone oxidoreductase (nqo)1, and heme oxygenase (ho)-1 antioxidant gene expression levels in the liver and intestine induced by DEL. Therefore, our study indicated that optimal α-LA (600 mg/kg) could attenuate DEL-induced toxicity (including liver damage, immunotoxicity, and oxidative stress) in northern snakehead via Nrf2/NF-κB signaling pathway. This is the first research that explores the alleviated effects of α-LA on DEL-induced toxicity damage in fish. This study provides a positive measure to reduce the toxicity damage caused by DEL to aquatic animals, and provides a theoretical basis for exploring the regulation mechanism of α-LA in toxic substances.

Safety and Efficacy of Intratympanic Alpha-Lipoic Acid Injection in a Mouse Model of Noise-Induced Hearing Loss

Alpha-lipoic acid (ALA) is an antioxidant with oto-protective effects. In the present study, the safety and effectiveness of ALA therapy after noise-induced hearing loss was confirmed based on the administration method. The safety of intratympanic ALA (IT-ALA) was evaluated with oto-endoscopy and middle ear mucosa morphologic study. Perilymph ALA concentrations according to the administration routes were compared, and the efficacy of ALA was investigated through hearing tests and cochlear histological studies. The middle ear mucosa was swollen 1 week after IT-ALA but completely recovered within 3 weeks. ALA concentration in the perilymph was significantly higher in the IT-ALA group. Recovery of organ of Corti morphology and hearing levels were predominant in the IT-ALA group compared with the intraperitoneal injection group (IP-ALA) and showed similar rescue effects in the IT-dexamethasone group (IT-DEX). Interleukin-1 beta and nuclear factor-kappa B expression was significantly downregulated in the IT-ALA group. IT-ALA showed better cochlear recovery from acoustic trauma with higher inner ear penetration rate than IP-ALA. The rescue effect of IT-ALA after noise-induced hearing loss was similar to IT-DEX; however, the ALA and DEX mechanisms are different. IT-ALA appears to be another safe and effective treatment modality after acoustic trauma and comparable to IT-DEX.

The effects of dietary supplementation of α-lipoic acid on the growth performance, antioxidant capacity, immune response, and disease resistance of northern snakehead, Channa argus

The study was the first time to explore the positive effects of α-LA on growth performance, antioxidant capability, immunity, and disease resistance of northern snakehead (Channa argus). Five hundred and forty northern snakehead fish (initial body weight: 8.74 ± 0.12 g (mean ± SE)) were randomly allocated into six groups with three replicates each. Six diets supplemented with α-LA at doses of 0 (CON), 300 (LA300), 600 (LA600), 900 (LA900), 1200 (LA1200), and 1500 (LA1500) mg/kg were fed to northern snakehead for 8 weeks. The results demonstrated that, when compared with the control group, optimal dietary α-LA increased the weight gain (WG), protein efficiency ratio (PER), and specific growth rate (SGR) and reduced the feed conversion ratio (FCR) of the fish (P < 0.05). Also, optimal dietary α-LA enhanced the immune-related parameters and antioxidant enzyme parameters levels in the head kidney, spleen, and liver of northern snakehead (P < 0.05). Dietary α-LA upregulated the mRNA expression levels of anti-inflammatory cytokines (il10 and tgfβ) and antioxidant related genes (gst, gsh-px, gr and Cu/Zn sod), down-regulated the pro-inflammatory cytokines (il1β, il8, il12 and tnfα) mRNA levels in the liver, spleen and head kidney of the northern snakehead (P < 0.05). The above results demonstrated that optimal dietary α-LA showed enhancement effects on the growth, antioxidant and anti-inflammatory capability, and immune response of northern snakehead. The survival rates in all α-LA treatments were significantly raised after the challenge with Aeromonas veronii (P < 0.05). Based on the quadratic regression analysis of WG, GSH-Px, LYS, and il1β, the optimal dietary α-LA levels were estimated to be 737.0, 775.0, 890.0, and 916.7 mg/kg, respectively. Considering the overall responses in growth performance, antioxidant status, immune response, and inflammatory factors, the recommended dose of α-LA in the diet of fish is 737.0-916.7 mg/kg.

Reactive Sulfur Compounds in the Fight against COVID-19

The SARS-CoV-2 coronavirus pandemic outbreak in 2019 resulted in the need to search for an effective and safe strategy for treating infected patients, relieving symptoms, and preventing severe disease. SARS-CoV-2 is an RNA virus that can cause acute respiratory failure and thrombosis, as well as impair circulatory system function. Permanent damage to the heart muscle or other cardiovascular disorders may occur during or after the infection. The severe course of the disease is associated with the release of large amounts of pro-inflammatory cytokines. Due to their documented anti-inflammatory, antioxidant, and antiviral effects, reactive sulfur compounds, including hydrogen sulfide (H₂S), lipoic acid (LA), N-acetylcysteine (NAC), glutathione (GSH), and some other lesser-known sulfur compounds, have attracted the interest of scientists for the treatment and prevention of the adverse effects of diseases caused by SARS-CoV-2. This article reviews current knowledge about various endogenous or exogenous reactive sulfur compounds and discusses the possibility, or in some cases the results, of their use in the treatment or prophylaxis of COVID-19.

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.

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.

Estimation of pharmacokinetic parameters of alpha-lipoic acid in the chicks model

Background and objective: Alpha-lipoic acid is a drug used to treat diabetic neuropathy, and it has other uses as a dietary supplement. The target of the study was to investigate the concentration of therapeutic doses of Alpha-lipoic acid in the blood plasma of broiler chicks to define the pharmacokinetic parameters. Methods: A randomized controlled study was performed on thirty-five healthy broiler chicks of seven days old, chicks were injected into the peritoneum with a single dose of analgesic ED50 80mg /kg b.wt, following injection of the drug, blood samples were collected at 0.25, 0.5, 1, 2, 4, 24 h (five chicks per time) from the jugular vein. Then the  blood plasma was obtained, the concentrations of Alpha-lipoic acid  in blood  plasma samples were determined utilizing UV Spectrometric Method, the pharmacokinetic parameters were determined by the PKSolver program. Time versus concentration curve for Alpha-lipoic acid was obtained from the program. The pharmacokinetic parameters were determined with non-compartmental models. Results: The concentration of Alpha-lipoic acid  in the blood plasma of chicks injected with Alpha lipoic at a dose (80 mg/kg) were 134.6±7.17, 178.5±4.10 ,192.4±7.83  ,158.5±11.05  ,147.1±10.16, 122.8±7.09  µg/ml at times   0.25, 0.5, 1, 2, 4, and 24 hours respectively. The maximum plasma concentration was 192.4µg/ml during a period of 1 hour of injection. The terminal elimination half-life was 65hours, the terminal phase elimination rate constant was 0.011 h-1 , the mean residence time was 94h, and the area under the curve from time 0 to infinity was 14960 µg.h/ml. Conclusions:  Our study concluded that the peak of the analgesic effect of alpha lipoic acid was one hour after treatment; furthermore, it is characterized by a long elimination half-life and a poor clearance from the chick’s body, which is reflected in the long effects of its pharmacological properties

α-Lipoic Acid Reduces Ceramide Synthesis and Neuroinflammation in the Hypothalamus of Insulin-Resistant Rats, While in the Cerebral Cortex Diminishes the β-Amyloid Accumulation

Background

Oxidative stress underlies metabolic diseases and cognitive impairment; thus, the use of antioxidants may improve brain function in insulin-resistant conditions. We are the first to evaluate the effects of α-lipoic acid (ALA) on redox homeostasis, sphingolipid metabolism, neuroinflammation, apoptosis, and β-amyloid accumulation in the cerebral cortex and hypothalamus of insulin-resistant rats.

Methods

The experiment was conducted on male cmdb/outbred Wistar rats fed a high-fat diet (HFD) for 10 weeks with intragastric administration of ALA (30 mg/kg body weight) for 4 weeks. Pro-oxidant and pro-inflammatory enzymes, oxidative stress, sphingolipid metabolism, neuroinflammation, apoptosis, and β-amyloid level were assessed in the hypothalamus and cerebral cortex using colorimetric, fluorimetric, ELISA, and HPLC methods. Statistical analysis was performed using three-way ANOVA followed by the Tukey HSD test.

Results

ALA normalizes body weight, food intake, glycemia, insulinemia, and systemic insulin sensitivity in HFD-fed rats. ALA treatment reduces nicotinamide adenine dinucleotide phosphate (NADPH) and xanthine oxidase activity, increases ferric-reducing antioxidant power (FRAP) and thiol levels in the hypothalamus of insulin-resistant rats. In addition, it decreases myeloperoxidase, glucuronidase, and metalloproteinase-2 activity and pro-inflammatory cytokines (IL-1β, IL-6) levels, while in the cerebral cortex ALA reduces β-amyloid accumulation. In both brain structures, ALA diminishes ceramide synthesis and caspase-3 activity. ALA improves systemic oxidative status and reduces insulin-resistant rats’ serum cytokines, chemokines, and growth factors.

Conclusion

ALA normalizes lipid and carbohydrate metabolism in insulin-resistant rats. At the brain level, ALA primarily affects hypothalamic metabolism. ALA improves redox homeostasis by decreasing the activity of pro-oxidant enzymes, enhancing total antioxidant potential, and reducing protein and lipid oxidative damage in the hypothalamus of HFD-fed rats. ALA also reduces hypothalamic inflammation and metalloproteinases activity, and cortical β-amyloid accumulation. In both brain structures, ALA diminishes ceramide synthesis and neuronal apoptosis. Although further study is needed, ALA may be a potential treatment for patients with cerebral complications of insulin resistance.

α-Lipoic Acid Strengthens the Antioxidant Barrier and Reduces Oxidative, Nitrosative, and Glycative Damage, as well as Inhibits Inflammation and Apoptosis in the Hypothalamus but Not in the Cerebral Cortex of Insulin-Resistant Rats

The research determined the role of α-lipoic acid (ALA) in reducing the brain manifestations of insulin resistance. The mechanism of ALA action is mainly based on its ability to “scavenge” oxygen free radicals and stimulate biosynthesis of reduced glutathione (GSH), considered the most critical brain antioxidant. Although the protective effect of ALA is widely documented in various diseases, there are still no studies assessing the influence of ALA on brain metabolism in the context of insulin resistance and type 2 diabetes. The experiment was conducted on male Wistar rats fed a high-fat diet for ten weeks with intragastric administration of ALA for four weeks. We are the first to demonstrate that ALA improves the function of enzymatic and nonenzymatic brain antioxidant systems, but the protective effects of ALA were mainly observed in the hypothalamus of insulin-resistant rats. Indeed, ALA caused a significant increase in superoxide dismutase, catalase, peroxidase, and glutathione reductase activities, as well as GSH concentration and redox potential ([GSH]²/[GSSG]) in the hypothalamus of HFD-fed rats. A consequence of antioxidant barrier enhancement by ALA is the reduction of oxidation, glycation, and nitration of brain proteins, lipids, and DNA. The protective effects of ALA result from hypothalamic activation of the transcription factor Nrf2 and inhibition of NF-κB. In the hypothalamus of insulin-resistant rats, we demonstrated reduced levels of oxidation (AOPP) and glycation (AGE) protein products, 4-hydroxynoneal, 8-isoprostanes, and 3-nitrotyrosine and, in the cerebral cortex, lower levels of 8-hydroxydeoxyguanosine and peroxynitrite. In addition, we demonstrated that ALA decreases levels of proinflammatory TNF-α but also increases the synthesis of anti-inflammatory IL-10 in the hypothalamus of insulin-resistant rats. ALA also prevents neuronal apoptosis, confirming its multidirectional effects within the brain. Interestingly, we have shown no correlation between brain and serum/plasma oxidative stress biomarkers, indicating the different nature of redox imbalance at the central and systemic levels. To summarize, ALA improves antioxidant balance and diminishes oxidative/glycative stress, protein nitrosative damage, inflammation, and apoptosis, mainly in the hypothalamus of insulin-resistant rats. Further studies are needed to determine the molecular mechanism of ALA action within the brain.

Low-Molecular-Weight Synthetic Antioxidants: Classification, Pharmacological Profile, Effectiveness and Trends

Mounting research has been performed and published on natural antioxidants, more so than on synthetic ones, as key molecules that control oxidative damage and its pathway to disease. Since the discovery of vitamins, various fully synthetic or natural-identical compounds have been developed as stable small molecules translated into constantly active and completely controlled products which are widely exploited in the food and pharmaceutical industries. There is currently a debate within the literature about their mechanism of action, bioavailability, safety and real benefit for human health. Using a semiquantitative method and eligible criteria of selection, this review aimed to provide a very useful classification of antioxidants and a comprehensive cross-disciplinary description of 32 approved synthetic/natural-identical antioxidants, in terms of regulatory, antioxidant mechanism of action, safety issues, pharmacological properties, effectiveness in human health, timeline and future trends. Enriched interpretation of the data was obtained from summary bibliometrics, useful to portray the “good antioxidant” within the period 1966–2021 and, hopefully, to encourage further research.

Nitric Oxide Is the Cause of Nitroglycerin Tolerance: Providing an Old Dog New Tricks for Acute Heart Failure

Our paper highlights the past 50 years of research focusing solely on tolerance involving nitroglycerin (glyceryl trinitrate, GTN). It also identifies and discusses inconsistencies in previous mechanistic explanations that have failed to provide a way to administer GTN continuously, free of limitations from tolerance and without the requirement of a nitrate-free interval. We illustrate, for the first time in 135 years, a mechanism whereby nitric oxide, the mediator of vasodilation by GTN, may also be the cause of tolerance. Based on targeting superoxide from mitochondrial complex I, uncoupled by glutathione depletion in response to nitric oxide from GTN, a novel unit dose GTN formulation in glutathione for use as a continuous i.v. infusion has been proposed. We hypothesize that this will reduce or eliminate tolerance seen currently with i.v. GTN. Finally, to evaluate the new formulation we suggest future studies of this new formulation for the treatment of acute decompensated heart failure.

Alpha lipoic acid toxicosis in cats (2008-2016): Four cases

OBJECTIVE

To review clinical signs, treatments, and outcome of 4 cases in cats after ingestion of alpha lipoic acid.

CASE SERIES SUMMARY

Four cases with known alpha lipoic acid ingestions developed clinical signs. A consistent clinical sign in all cases was vomiting, while 2 of the 4 cases resulted in death.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first reported case series of alpha lipoic acid ingestions in cats.

Lipoic Acid-Coated Silver Nanoparticles: Biosafety Potential on the Vascular Microenvironment and Antibacterial Properties

Purpose: To study and compare the antibacterial properties and the potential cytotoxic effects of commercially available uncoated silver nanoparticles (AgNPs) with lipoic acid coated silver nanoparticles (AgNPsLA) developed by our group. The antibacterial, cytotoxic, and hemolytic properties of those NPs were assessed with the main objective of investigating if AgNPsLA could maintain their antibacterial properties while improving their biosafety profile over uncoated AgNPs within the blood vessel's microenvironment. Methods: Comercially available uncoated 2.6 nm AgNPs and 2.5 nm AgNPsLA synthesized and characterized as previously described by our group, were used in this study. Antimicrobial activity was assessed on a wide range of pathogens and expressed by minimal inhibitory concentrations (MIC). Assessment of cytotoxicity was carried out on human umbilical vein endothelial cells (HUVEC) using an MTT test. Detection of reactive oxygen species, cell apoptosis/necrosis in HUVEC, and measurement of mitochondrial destabilization in HUVEC and platelets were performed by flow cytometry. The potential harmful effect of nanoparticles on red blood cells (RBCs) was investigated measuring hemoglobin and LDH released after exposure to NPs. Transmission electron microscopy was also used to determine if AgNPs and AgNPsLA could induce any ultrastructural changes on HUVEC cells and Staphylococcus aureus bacteria. Results: AgNPs and AgNPsLA had antimicrobial properties against pathogens associated with catheter-related bloodstream infections. AgNPs, in contrast to AgNPsLA, induced ROS production and apoptosis in HUVEC, ultrastructural changes in HUVEC and S. aureus, depolarization of mitochondrial membrane in HUVEC and platelets, and also hemolysis. Conclusion: AgNPsLA synthesized by our group have antimicrobial activity and a better biosafety profile than uncoated AgNPs of similar size. Those observations are of critical importance for the future in vivo investigations and the potential application of AgNPsLA in medical devices for human use.

Alpha-Lipoic Acid Inhibits Spontaneous Diabetes and Autoimmune Recurrence in Non-Obese Diabetic Mice by Enhancing Differentiation of Regulatory T Cells and Showed Potential for Use in Cell Therapies for the Treatment of Type 1 Diabetes

Type 1 diabetes (T1D) is caused by the destruction of β cells in pancreatic islets by autoimmune T cells. Islet transplantation has been established as an effective treatment for T1D. However, the survival of islet grafts is often disrupted by recurrent autoimmunity. Alpha-lipoic acid (ALA) has been reported to have immunomodulatory effects and, therefore, may have therapeutic potential in the treatment of T1D. In this study, we investigated the therapeutic potential of ALA in autoimmunity inhibition. We treated non-obese diabetic (NOD) mice with spontaneous diabetes and islet-transplantation mice with ALA. The onset of diabetes was decreased and survival of the islet grafts was extended. The populations of Th1 cells decreased, and regulatory T cells (Tregs) increased in ALA-treated mice. The in vitro Treg differentiation was significantly increased by treatment with ALA. The adoptive transfer of ALA-differentiated Tregs into NOD recipients improved the outcome of the islet grafts. Our results showed that in vivo ALA treatment suppressed spontaneous diabetes and autoimmune recurrence in NOD mice by inhibiting the Th1 immune response and inducing the differentiation of Tregs. Our study also demonstrated the therapeutic potential of ALA in Treg-based cell therapies and islet transplantation used in the treatment of T1D.