The Effect of 600 mg Alpha-lipoic Acid Supplementation on Oxidative Stress, Inflammation, and RAGE in Older Adults with Type 2 Diabetes Mellitus

Integrated approach to reducing polypharmacy in older people: exploring the role of oxidative stress and antioxidant potential therapy

Increased life expectancy, attributed to improved access to healthcare and drug development, has led to an increase in multimorbidity, a key contributor to polypharmacy. Polypharmacy is characterised by its association with a variety of adverse events in the older persons. The mechanisms involved in the development of age-related chronic diseases are largely unknown; however, altered redox homeostasis due to ageing is one of the main theories. In this context, the present review explores the development and interaction between different age-related diseases, mainly linked by oxidative stress. In addition, drug interactions in the treatment of various diseases are described, emphasising that the holistic management of older people and their pathologies should prevail over the individual treatment of each condition.

Effects of alfa lipoic acid and coenzyme Q10 treatment on AFB1-induced oxidative, inflammatory, and DNA damages in rats

Food contamination with Aflatoxin B1 (AFB1) is a worldwide concern that adversely affects animal and human health. The study aimed to evaluate the protective effect of alpha lipoic acid (ALA) and/or co-enzyme Q10 (CQ10) against the harmful effects of AFB1 on the liver and kidneys. Fifty-six mature male Wistar Albino rats (180-200 g) were divided into seven groups, each with eight rats: (1) saline was given as a control, (2) ALA (100 mg/kg bw/day) was given by stomach gavage for fifteen days, and (3) CQ10 (10 mg/kg bw/day) was given by stomach gavage for fifteen days. Group (4) orally given AFB1 (2.5 mg/kg bw) on days 12th and 14th, (5) received AFB1 and ALA, (6) received AFB1 and CQ10, and (7) received AFB1, ALA, and CQ10, as previously described in the ALA, CQ10, and AFB1 groups. After the exposure to AFB1, a significant increase in liver markers (AST, ALT, ALP, and LDH) and renal function tests (BUN and creatinine) was observed compared with the control. ALA and/or CQ10 significantly reduced enzymes of liver and renal functions, as compared with AFB1. AFB1 exposure threw off the balance between oxidants and antioxidants. Still, ALA and/or CQ10 made oxidative stress (MDA, NO, and 8-OHdG) much lower and antioxidant activities (GSH, GSH-Px, SOD, and CAT) much higher. When we used the two together, the activities matched the control levels. Interestingly, this study shows that ALA and CQ10 significantly lowered IL-1β, IL-6, and TNF-α levels compared to the control values when used together after AFB1 exposure caused robust inflammation. Some CQ10 treatment parameters significantly outperformed those of ALA. ALA and CQ10 together worked better than either one alone to protect against AFB1-induced toxicity in the hepatic and renal parenchyma in terms of reducing inflammation, preventing DNA damage, and fighting free radicals.

Evaluation of Safety and Efficacy of Add-on Alpha-Lipoic Acid on Migraine Prophylaxis in an Adolescent Population: A Randomized Controlled Trial

Nutraceuticals like alpha-lipoic acid (ALA) may have potential benefits as prophylactic agents for adolescent migraine, with fewer adverse events than existing medications. The present study was conducted to evaluate the safety and efficacy of add-on ALA for prophylaxis in adolescent migraine. A randomized, open-label, add-on clinical trial was conducted with 60 adolescent migraineurs, who were randomized to receive flunarizine or flunarizine with an add-on ALA. A clinical evaluation of the frequency and severity of migraine, responder rate, Pediatric Migraine Disability Assessment (PedMIDAS) scoring, serum thiol, and serum calcitonin gene-related peptide (CGRP) was performed both at baseline and following 12 weeks of treatment. The frequency of acute attacks of migraine decreased significantly (P = .001) in the test group compared with the control group. The responder rate was found to be significantly higher (80%) in the test group than in the control group (33.3%) (P = .001). The mean monthly migraine headache days in the test group showed a significant reduction (-7.7 days, 95%CI -9.1 to -6.3 days; P = .010). The severity of acute migraine attacks (mild, moderate, severe) also showed a significant reduction in the test group (P = .001). PedMIDAS scores showed significant improvement in the test group (P = .021), in comparison with the control group. Serum thiol levels were significantly increased in the test group (18 mmol/L, 95%CI 13.5 to 36.1 mmol/L; P = .001). Serum CGRP levels showed a significant reduction with adjunctive ALA therapy (-122.4 pg/mL, 95%CI -142.3 to -89.0 pg/mL; P = .006). Add-on ALA with flunarizine as a prophylactic agent for migraine in adolescents can improve clinical outcomes by improving clinical and biochemical parameters.

The effects of alpha lipoic acid (ALA) supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

Introduction

There have been various clinical studies on the effect of Alpha lipoic acid (ALA) supplementation on blood pressure (BP), but the findings from these are contradictory. Therefore, we performed a systematic review and dose-response meta-analysis to summarize the relation of ALA supplementation and systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults.

Methods

A comprehensive search was conducted in Medline (PubMed), Embase, Scopus, and ProQuest up to July 2023. Randomized controlled trials (RCTs) evaluating the effect of ALA on SBP and DBP were included. The pooled weighted mean difference (WMD) of included trials was estimated using a random-effects model. The dose-dependent effect was also assessed.

Results and discussion

A total of 11 RCTs with the participation of 674 patients were included. The result of the meta-analysis indicated that using ALA supplementation significantly reduced the SBP (WMD = -5.46 mmHg; 95% CI: -9.27, -1.65; p < 0.001) and DBP (WMD = -3.36 mmHg, 95% CI: -4.99, -1.74; p < 0.001). The ALA administrations significantly reduced SBP and DBP at the dosages of <800 mg/day, when administered for ≤12 weeks. The present meta-analysis revealed that ALA supplementation could exert favorable effects on SBP and DBP. Further well-designed studies with larger samples are needed to ascertain the long-term effects of ALA on BP.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=447658, identifier PROSPERO: CRD42023447658.

Oxidative stress as a culprit in diabetic kidney disease

Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease (ESRD), and the prevalence of DKD has increased worldwide during recent years. DKD is associated with poor therapeutic outcomes in most patients, but there is limited understanding of its pathogenesis. This review suggests that oxidative stress interacts with many other factors in causing DKD. Highly active mitochondria and NAD(P)H oxidase are major sources of oxidants, and they significantly affect the risk for DKD. Oxidative stress and inflammation may be considered reciprocal causes of DKD, in that each is a cause and an effect of DKD. Reactive oxygen species (ROS) can act as second messengers in various signaling pathways and as regulators of metabolism, activation, proliferation, differentiation, and apoptosis of immune cells. Epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNAs can modulate oxidative stress. The development of new technologies and identification of new epigenetic mechanisms may provide novel opportunities for the diagnosis and treatment of DKD. Clinical trials demonstrated that novel therapies which reduce oxidative stress can slow the progression of DKD. These therapies include the NRF2 activator bardoxolone methyl, new blood glucose-lowering drugs such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists. Future studies should focus on improving early diagnosis and the development of more effective combination treatments for this multifactorial disease.

EFFECTS OF ALPHA-LIPOIC ACID ON GLYCEMIC STATUS IN 2 TYPE DIABETES PATIENTS WITH СHRONIC CORONARY SYNDROME

OBJECTIVE

The aim: To study the possibilities of alpha-lipoic acid (ALA) to control the parameters of carbohydrate metabolism.

PATIENTS AND METHODS

Materials and methods: We examined 80 people with type 2 DM and coronary heart disease who suffered non-Q-myocardial infarction (non-Q-MI). All patients at the time of inclusion in the study received oral hypoglycemic agents, ACE inhibitor, β-blocker, statin and antiplatelet agent. 600 mg of ALA per day for 4 months was added to this treatment. After checking the patients for compliance with the criteria, they were divided into the main and experimental groups. The dosage of alpha-lipoic acid was determined for each of the groups. The results of the treatment were analyzed by determining the mean and standard deviations.

RESULTS

Results: At the end of the observation period, a significant decrease in the level of fasting glucose (FG) by 11.6% was found, which corresponded to the average size of the clinical effect. The values of glycosylated hemoglobin (HbA1c) and the insulin resistance index HOMA (HOMA-IR) showed only a tendency to decrease on the background of treatment. The effect of ALA on postprandial glycemia (PPG) and insulin levels was not detected in this study.

CONCLUSION

Conclusions: An additional 4-month dose of ALA in addition to baseline therapy showed a moderate effect on the decrease in FG concentration in the absence of significant dynamics in other parameters of glycemic control in the examined patients.

Neuroprotective Effect of Ponicidin Alleviating the Diabetic Cognitive Impairment: Regulation of Gut Microbiota

Cognitive impairment is a major complication of diabetes mellitus, which is caused by constitutive hyperglycaemia. Ponicidin is a diterpenoid isolated from a Chinese traditional herb (Rabdosia rubescens) and demonstrates the various pharmacological effects. The goal of this study was to scrutinise the neuroprotective effect of ponicidin against diabetic nephropathy (DN) induced by streptozotocin (STZ). Intraperitoneal administration of STZ (55 mg/kg) was used for the induction of diabetes and rats were received oral administration of ponicidin (5, 10 and 15 mg/kg) until 28 days. The body weight, food intake, water intake and blood glucose level were assessed at regular time interval. Plasma insulin level, antioxidant, inflammatory cytokines, apoptosis marker and faecal gut microbiota compositions were estimated. DN-induced group rats revealed the augmented glucose level, water intake, food intake and reduced body weight. Ponicidin significantly (P < 0.001) repressed the glucose level and water food intake and improved the body weight and plasma insulin. Ponicidin significantly (P < 0.001) repressed the malonaldehyde (MDA) level and boosted the level of glutathione (GSH), glutathione reductase (GR) and superoxide dismutase (SOD) in the brain and serum level. Ponicidin significantly (P < 0.001) repressed the level of interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and enhanced the level of interleukin-4 (IL-4), interleukin-10 (IL-10) in the brain and serum level. DN group rats exhibited the enhanced relative abundance of Firmicutes, along with enhancing the Firmicutes/Bacteroidetes ratio and repressing the Bacteroidetes relative abundance. Ponicidin effectually restored the relative abundance of Allobaculum, Lactobacillus and Ruminococcus genera. Our findings clearly demonstrated that ponicidin has a neuroprotective effect against diabetic cognitive impairment through modulating the gut microbiome.

Role of Oxidative Stress in the Pathogenesis of Atherothrombotic Diseases

Oxidative stress is generated by the imbalance between reactive oxygen species (ROS) formation and antioxidant scavenger system’s activity. Increased ROS, such as superoxide anion, hydrogen peroxide, hydroxyl radical and peroxynitrite, likely contribute to the development and complications of atherosclerotic cardiovascular diseases (ASCVD). In genetically modified mouse models of atherosclerosis, the overexpression of ROS-generating enzymes and uncontrolled ROS formation appear to be associated with accelerated atherosclerosis. Conversely, the overexpression of ROS scavenger systems reduces or stabilizes atherosclerotic lesions, depending on the genetic background of the mouse model. In humans, higher levels of circulating biomarkers derived from the oxidation of lipids (8-epi-prostaglandin F_2α, and malondialdehyde), as well as proteins (oxidized low-density lipoprotein, nitrotyrosine, protein carbonyls, advanced glycation end-products), are increased in conditions of high cardiovascular risk or overt ASCVD, and some oxidation biomarkers have been reported as independent predictors of ASCVD in large observational cohorts. In animal models, antioxidant supplementation with melatonin, resveratrol, Vitamin E, stevioside, acacetin and n-polyunsaturated fatty acids reduced ROS and attenuated atherosclerotic lesions. However, in humans, evidence from large, placebo-controlled, randomized trials or prospective studies failed to show any athero-protective effect of antioxidant supplementation with different compounds in different CV settings. However, the chronic consumption of diets known to be rich in antioxidant compounds (e.g., Mediterranean and high-fish diet), has shown to reduce ASCVD over decades. Future studies are needed to fill the gap between the data and targets derived from studies in animals and their pathogenetic and therapeutic significance in human ASCVD.

Treatment and prevention of pathological mitochondrial dysfunction in retinal degeneration and in photoreceptor injury

Pathological deterioration of mitochondrial function is increasingly linked with multiple degenerative illnesses as a mediator of a wide range of neurologic and age-related chronic diseases, including those of genetic origin. Several of these diseases are rare, typically defined in the United States as an illness affecting fewer than 200,000 people in the U.S. population, or about one in 1600 individuals. Vision impairment due to mitochondrial dysfunction in the eye is a prominent feature evident in numerous primary mitochondrial diseases and is common to the pathophysiology of many of the familiar ophthalmic disorders, including age-related macular degeneration, diabetic retinopathy, glaucoma and retinopathy of prematurity - a collection of syndromes, diseases and disorders with significant unmet medical needs. Focusing on metabolic mitochondrial pathway mechanisms, including the possible roles of cuproptosis and ferroptosis in retinal mitochondrial dysfunction, we shed light on the potential of α-lipoyl-L-carnitine in treating eye diseases. α-Lipoyl-L-carnitine is a bioavailable mitochondria-targeting lipoic acid prodrug that has shown potential in protecting against retinal degeneration and photoreceptor cell loss in ophthalmic indications.

Discovery of Therapeutics Targeting Oxidative Stress in Autosomal Recessive Cerebellar Ataxia: A Systematic Review

Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of rare neurodegenerative inherited disorders. The resulting motor incoordination and progressive functional disabilities lead to reduced lifespan. There is currently no cure for ARCAs, likely attributed to the lack of understanding of the multifaceted roles of antioxidant defense and the underlying mechanisms. This systematic review aims to evaluate the extant literature on the current developments of therapeutic strategies that target oxidative stress for the management of ARCAs. We searched PubMed, Web of Science, and Science Direct Scopus for relevant peer-reviewed articles published from 1 January 2016 onwards. A total of 28 preclinical studies fulfilled the eligibility criteria for inclusion in this systematic review. We first evaluated the altered cellular processes, abnormal signaling cascades, and disrupted protein quality control underlying the pathogenesis of ARCA. We then examined the current potential therapeutic strategies for ARCAs, including aromatic, organic and pharmacological compounds, gene therapy, natural products, and nanotechnology, as well as their associated antioxidant pathways and modes of action. We then discussed their potential as antioxidant therapeutics for ARCAs, with the long-term view toward their possible translation to clinical practice. In conclusion, our current understanding is that these antioxidant therapies show promise in improving or halting the progression of ARCAs. Tailoring the therapies to specific disease stages could greatly facilitate the management of ARCAs.

Effects of berberine on leukemia with a focus on its molecular targets

Leukemia is a common cancer among both women and men worldwide. Besides the fact that finding new treatment methods may enhance the life quality of patients, there are several problems that we face today in treating leukemia patients, such as drugs side effects and acquired resistance to chemotherapeutic drugs. Berberine is a bioactive alkaloid found in herbal plants (e.g. Rhizoma coptidis and Cortex phellodendri) and exerts several beneficial functions, including anti-tumor activities. Furthermore, berberine exerts antiproliferative and anti-inflammatory effects. Up to now, some studies have investigated the roles of berberine in different types of leukemia, including acute myeloid leukemia and chronic lymphocytic leukemia. In this review, a detailed description of berberine roles in leukemia is provided. We discuss how berberine involves different molecular targets (e.g. interleukins and cyclins) and signaling pathways (e.g. mTOR and PI3K) to exert its anti-tumor functions and how berberine is effective in leukemia treatment when combined with other therapeutic drugs.

Current Strategies for the Management of Painful Diabetic Neuropathy

The development of painful diabetic neuropathy (PDN) is a common complication of chronic diabetes that can be associated with significant disability and healthcare costs. Prompt symptom identification and aggressive glycemic control is essential in controlling the development of neuropathic complications; however, adequate pain relief remains challenging and there are considerable unmet needs in this patient population. Although guidelines have been established regarding the pharmacological management of PDN, pain control is inadequate or refractory in a high proportion of patients. Pharmacotherapy with anticonvulsants (pregabalin, gabapentin) and antidepressants (duloxetine) are common first-line agents. The use of oral opioids is associated with considerable morbidity and mortality and can also lead to opioid-induced hyperalgesia. Their use is therefore discouraged. There is an emerging role for neuromodulation treatment modalities including intrathecal drug delivery, spinal cord stimulation, and dorsal root ganglion stimulation. Furthermore, consideration of holistic alternative therapies such as yoga and acupuncture may augment a multidisciplinary treatment approach. This aim of this review is to focus on the current management strategies for the treatment of PDN, with a discussion of treatment rationale and practical considerations for their implementation.

A promising discovery of anti-aging chemical conjugate derived from lipoic acid and sesamol established in Drosophila melanogaster

Phytonutrients, lipoic acid and sesamol, were chemically combined to yield medically important lipoic acid-sesamol conjugate (LSC). NMR and LC-MS/MS techniques were used to determine the chemical structure of LSC. The...

Effect of Low-Dose Gamma Radiation and Lipoic Acid on High- Radiation-Dose Induced Rat Brain Injuries

Aim

This work aims to investigate the possible radio-adaptive mechanisms induced by low-dose (LD) whole-body γ-irradiation alone or combined with alpha-lipoic acid (ALA) administration in modulating high-dose (HD) head irradiation–induced brain injury in rats.

Materials and Methods

Rats were irradiated with LD (.25 Gy) 24 hours prior HD (20 Gy), and subjected to ALA (100 mg/kg/day) 5 minutes after HD and continued for 10 days. At the end of the experiment, animals were sacrificed and brain samples were dissected for biochemical and histopathological examinations.

Results

HD irradiation-induced brain injury as manifested by elevation of oxidative stress, DNA damage, apoptotic, and inflammatory markers in brain tissue. Histological examination of brain sections showed marked alterations. However, LD alone or combined with ALA ameliorated the changes induced by HD.

Conclusion

Under the present experimental conditions, LD whole-body irradiation exhibited neuroprotective activity against detrimental effects of a subsequent HD head irradiation. This effect might be due to the adaptive response induced by LD that activated the anti-oxidative, anti-apoptotic, and anti-inflammatory mechanisms in the affected animals making them able to cope with the subsequent high-dose exposure. However, the combined LD exposure and ALA supplementation produced a further modulating effect in the HD-irradiated rats.

An updated systematic review and dose-response meta-analysis of the randomized controlled trials on the effects of Alpha-Lipoic acid supplementation on inflammatory biomarkers

Data about the effects of alpha-lipoic acid (ALA) supplementation on inflammatory markers are inconsistent. This systematic review and dose-response meta-analysis of randomized controlled trials was performed to summarize the effects of ALA supplementation on inflammatory markers such as C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in adults. A comprehensive literature search was conducted in the electronic databases of PubMed, Web of Science, ProQuest, Embase, and SCOPUS from inception to February 2020. Among all of the eligible studies, 20 articles were selected. The weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated to evaluate the pooled effect size. Between-study heterogeneity was evaluated using Cochran's Q test and I². Subgroup analysis was done to evaluate the potential sources of heterogeneity. The dose-response relationship was evaluated using fractional polynomial modeling. Twenty eligible studies with a total sample size of 947 participants were included in the current meta-analysis. The findings of the meta-analysis showed that ALA supplementation significantly reduced CRP (WMD: -0.69 mg/L, 95% CI: -1.13, -0.26, P=0.002), IL-6 (WMD: -1.83 pg/ml, 95% CI: -2.90, -0.76, P=0.001), and TNF-α concentrations (WMD: -0.45 pg/ml, 95% CI: -0.85, -0.04, P=0.032). No evidence of departure from linearity was observed between dose and duration of the ALA supplementation on serum CRP, IL-6 and TNF-α concentration. In subgroup analysis, ALA dosage, baseline concentrations of the parameter, sample size, and gender were considered as possible sources of heterogeneity. In summary, ALA supplementation improves inflammatory markers without any evidence of non-linear association to dose or duration of the trial.

Lipid peroxidation processes in men with type 1 diabetes mellitus following α-lipoic acid treatment

<abstract> <p>In various pathological conditions such as diabetes mellitus, the cellular redox balance can be disturbed and these alterations may persist even after blood glucose levels have returned to normal. Antioxidant therapies, including α-lipoic acid, are widely used to treat various systemic diseases including diabetes mellitus. The aim of this study was to measure the lipid metabolism parameters, as well as the activity of lipid peroxidation and antioxidant defense reactions, in men with type 1 diabetes mellitus (T1DM) during treatment with α-lipoic acid. Twenty-four reproductive-age T1DM males with an unsatisfactory glycemic profile were examined. Twenty-eight practically healthy men of similar age were used as the control group. Spectrophotometric, fluorometric, and enzyme-linked immunoassay methods were used. T1DM was characterized by increased values of lipid metabolism components, including total cholesterol, triacylglycerides (TG), and very-low-density lipoproteins (VLDL). In the lipid peroxidation system, increased levels of the primary products (conjugated dienes), secondary products (thiobarbituric acid reactants), and final products (Schiff bases) were observed in T1DM patients compared to the control group. Retinol values were also increased. After treatment, there was a decrease in TG, VLDL, and Schiff bases levels and an increase in the retinol level compared to before treatment. These results expand our understanding of the pathogenetic mechanisms of T1DM and suggest that α-LA treatment may be beneficial for type 1 diabetics.</p> </abstract>

The effects of alpha lipoic acid on muscle strength recovery after a single and a short-term chronic supplementation - a study in healthy well-trained individuals after intensive resistance and endurance training

Background

Alpha lipoic acid (ALA) has been demonstrated to have anti-inflammatory activity and was tested as a drug for the treatment of various diseases. ALA is also frequently used as a nutrition supplement, in healthy individuals or in competitive athletes. However, information from intervention studies investigating physiological effects of an ALA in athletes after exercise is limited. Therefore, the aim of this study was to investigate the effects of single and short-term chronic ALA supplementation on the muscle strength recovery and performance of athletes after intensive exercise.

Methods

In a double-blind, randomised, controlled trial in cross-over design, 17 male resistance and endurance-experienced athletes successfully participated. The subjects were divided into two groups (ALA and Placebo) and underwent a standardized single training session and a high intense training week. At certain time points (T0, T1a (+ 3 h), T1b (+ 24 h) and T2 (+7d)) blood samples were taken and markers for muscle damage, inflammation and oxidative stress were investigated. In addition, the maximum performance in the back squat was measured at all time points.

Results

In the chronic training experiment, a moderate inhibition of muscle damage and inflammation could be observed in the ALA-group. Performance in the back squat was significantly reduced in the placebo-group, but not in the ALA-group. No anti-oxidative effects could be observed.

Conclusions

Our data indicate possible effects of ALA supplementation, during intensive training periods result in a reduction of muscle damage, inflammation and an increase of recovery. Whether ALA supplementation in general may enhance performance and the exact training / supplementation scenarios needs to be investigated in future studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12970-020-00389-y.

Safety Evaluation of α-Lipoic Acid Supplementation: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Clinical Studies

Alpha-lipoic acid (ALA) is a natural short-chain fatty acid that has attracted great attention in recent years as an antioxidant molecule. However, some concerns have been recently raised regarding its safety profile. To address the issue, we aimed to assess ALA safety profile through a systematic review of the literature and a meta-analysis of the available randomized placebo-controlled clinical studies. The literature search included EMBASE, PubMed Medline, SCOPUS, Google Scholar, and ISI Web of Science by Clarivate databases up to 15th August 2020. Data were pooled from 71 clinical studies, comprising 155 treatment arms, which included 4749 subjects with 2558 subjects treated with ALA and 2294 assigned to placebo. A meta-analysis of extracted data suggested that supplementation with ALA was not associated with an increased risk of any treatment-emergent adverse event (all p > 0.05). ALA supplementation was safe, even in subsets of studies categorized according to smoking habit, cardiovascular disease, presence of diabetes, pregnancy status, neurological disorders, rheumatic affections, severe renal impairment, and status of children/adolescents at baseline.

An updated systematic review and dose-response meta-analysis of the effects of α-lipoic acid supplementation on glycemic markers in adults

This systematic review and dose-response meta-analysis was conducted to summarize data from available clinical trials on the effects of α-lipoic acid (ALA) supplementation on glycemic markers including glucose, hemoglobin A_1c (HbA_1c), insulin, homeostatic model assessment of insulin resistance (HOMA-IR), HOMA-β, and quantitative insulin check index in adults. A comprehensive literature search was conducted in the electronic databases of PubMed, Web of Science, ProQuest, Embase and SCOPUS from inception to February 2020. Among all of the eligible studies, 28 articles were selected. The weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated to evaluate the pooled effect size. Between-study heterogeneity was evaluated using Cochran's Q test and I². Subgroup analysis was done to evaluate the potential sources of heterogeneity. The dose-response relationship was evaluated using fractional polynomial modeling. Twenty eight eligible studies with a total sample size of 1,016 participants were included in the current meta-analysis. The findings of the meta-analysis showed that ALA supplementation significantly reduced insulin (WMD: -0.64; CI: -1.287 to 0.004, P = .04), HOMA-IR (WMD: -0.48; 95% CI: -0.79 to -0.16; P = .002). No change in glucose or HbA1C was reported. Moreover, the effect of ALA on insulin was duration-dependent (P_{non-linearity} = 0.04). No evidence of departure from linearity was observed between dose and duration of the ALA supplementation on other markers. The subgrouping revealed that ALA dosage and duration of ALA supplementation, health status of participants, geographic locations and the studies' quality are possible sources of heterogeneity. In summary, ALA supplementation improves serum insulin and insulin resistance in a two-class and duration dependent non-linear analysis.

The Protective Role of Prenatal Alpha Lipoic Acid Supplementation against Pancreatic Oxidative Damage in Offspring of Valproic Acid-Treated Rats: Histological and Molecular Study

Background: Sodium valproate (VPA) is an antiepileptic drug (AED) licensed for epilepsy and used during pregnancy in various indications. Alpha-lipoic acid (ALA) is a natural compound inducing endogenous antioxidant production. Our study aimed to investigate the effect of prenatal administration of VPA on the pancreas of rat offspring and assess the potential protective role of ALA co-administration during pregnancy. Methods: Twenty-eight pregnant female albino rats were divided into four groups: group I (negative control), group II (positive control, ALA treated), group III (VPA-treated), and group IV (VPA-ALA-treated). The pancreases of the rat offspring were removed at the fourth week postpartum and prepared for histological, immune-histochemical, morphometric, molecular, and oxidative stress marker studies. Results: In group III, there were pyknotic nuclei, vacuolated cytoplasm with ballooning of acinar, α, and β cells of the pancreas. Ultrastructural degeneration of cytoplasmic organelles was detected. Additionally, there was a significant increase in oxidative stress, a decrease in insulin-positive cell percentage, and an increase in glucagon positive cells in comparison to control groups. Moreover, VPA increased the gene expression of an apoptotic marker, caspase-3, with a decrease in anti-apoptotic Bcl2 and nuclear factor erythroid 2-related factor 2 (Nrf2) transcriptional factor. Conversely, ALA improved oxidative stress and apoptosis in group VI, and a consequent improvement of the histological and ultrastructure picture was detected. Conclusion: ALA co-administration with VPA significantly improved the oxidative stress condition, histological and morphometric picture of the pancreas, and restored normal expression of related genes, including Nrf2, caspase-3, and Bcl-2. Administration of α-lipoic acid has a protective effect against VPA-induced pancreatic oxidative damage via its cytoprotective antioxidant effect.

Selenium-Containing Protein From Selenium-Enriched Spirulina platensis Attenuates High Glucose-Induced Calcification of MOVAS Cells by Inhibiting ROS-Mediated DNA Damage and Regulating MAPK and PI3K/AKT Pathways

Hyperglycemia is the main feature of diabetes and may increase the risk of vascular calcification (VC), which is an independent predictor for cardiovascular and cerebrovascular diseases (CCD). Selenium (Se) may decrease the risk of CCD, and previous studies confirmed that Se-containing protein from Se-enriched Spirulina platensis (Se-SP) exhibited novel antioxidant potential. However, the effect of Se-SP against VC has been not investigated. Herein, the protective effect and underlying mechanism of Se-SP against high glucose-induced calcification in mouse aortic vascular smooth muscle cells (MOVAS) were explored. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) results showed time-dependent uptake of Se-SP in MOVAS cells, which significantly inhibited high glucose-induced abnormal proliferation. Se-SP co-treatment also effectively attenuated high glucose-induced calcification of MOVAS cells, followed by decreased activity and expression of alkaline phosphatase (ALP). Further investigation revealed that Se-SP markedly prevented reactive oxygen species (ROS)-mediated DNA damage in glucose-treated MOVAS cells. ROS inhibition by glutathione (GSH) effectively inhibited high glucose-induced calcification, indicating that Se-SP could act as ROS inhibitor to inhibit high glucose-induced DNA damage and calcification. Moreover, Se-SP dramatically attenuated high glucose-induced dysfunction of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3-kinase/AKT (PI3K/AKT) pathways. Se-SP after Se addition achieved enhanced potential in inhibiting high glucose-induced calcification, which validated that Se-SP as a new Se species could be a highly effective treatment for human CCD.

Strawberry Leaf Extract Treatment Alleviates Cognitive Impairment by Activating Nrf2/HO-1 Signaling in Rats With Streptozotocin-Induced Diabetes

Diabetes-associated cognitive impairment (DACI) is a common complication of diabetes mellitus (DM) that affects the central nervous system. Cognitive impairment, such as learning and memory impairment, and even dementia, is the main clinical manifestation of DACI. Unfortunately, there is no effective means by which to delay the cognitive symptoms of DM. Evidence has shown that strawberry leaf extract could alleviate cognitive decline, suppress oxidative stress, and reduce inflammatory responses in rats. In the present study, we evaluated the effect of strawberry leaf extract on cognitive function in a rat model of streptozotocin (STZ)-induced diabetes. After the continuous administration of strawberry leaf extract for 4 weeks, the Morris Water Maze (MWM) test results showed that the cognitive impairment of the rats was alleviated. Moreover, strawberry leaf extract significantly reduced the level of reactive oxygen species (ROS), decreased the level of malondialdehyde (MDA), improved the activity of superoxide dismutase (SOD) and catalase (CAT), decreased the mRNA expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and decreased the protein expression of caspase-3 and caspase-9 in the hippocampus of DM rats. Also, transcription factor nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2)/hemeoxygenase-1(HO-1) signaling was activated by the administration of strawberry leaf extract. Our findings indicate that strawberry leaf extract may be a potential drug candidate for the treatment of DACI and may be used as a basis for further research on the development of drugs for cognitive impairment in diabetes.

Alpha-Lipoic Acid as a Means of Influence on Systemic Inflammation in Type 2 Diabetes Mellitus Patients with Prior Myocardial Infarction

Patients with combined coronary heart disease and diabetes mellitus make up a growing segment of the population and require a comprehensive treatment approach. Patients with concurrent diabetes mellitus and coronary heart disease have a worse projection. Under these conditions, the incidence of recurrent myocardial infarction, early disability due to complications, and the risk of coronary death are increased. Therefore, the priority task is to find ways to optimize drug treatment of this category of patients, taking into account the impact of drugs on the pathogenetic links of coronary heart disease progression and the development of cardiovascular complications. One hundred twelve people were examined in the research. The patients had type 2 diabetes with a history of non-Q-myocardial infarction receiving oral antidiabetic therapy and basic therapy, including an ACE inhibitor, a β-blocker, a statin, and an antiplatelet agent. Analysis of the investigated parameters in the leading group after receiving alpha-lipoic acid for 4 months showed a significant decrease in the concentration of C-Reactive Protein, IL-6 and TNF-α. According to the results of our research, taking alpha-lipoic acid for 4 months in patients with type 2 diabetes who underwent non-Q-myocardial infarction reduced the activity of systemic inflammation and did not significantly affect the content of anti-inflammatory IL-10 in patients. In light of the above, it is of interest to administer alpha-lipoic acid to these patients, considering the positive effects of the agent such as antioxidant properties, vasorelaxation, positive metabolic profile, as well as an anti-inflammatory potential.

Alpha-lipoic acid supplementation significantly reduces the risk of obesity in an updated systematic review and dose response meta-analysis of randomised placebo-controlled clinical trials

BACKGROUND

There are numerous trials reported the effect of alpha-lipoic acid (ALA) on obesity measurements; while no summarised dose-response meta-analysis is available to address the effects of dose and duration of ALA supplementation on obesity measurements. We aimed to summarise the results of studies evaluating the effects of ALA supplementation on obesity measurements in a systematic review and dose-response meta-analysis.

METHODS AND MATERIALS

In a systematic search from Scopus, PubMed, Embase, Proquest electronic databases up to January 2020 relevant studies were retrieved. Randomised, placebo-controlled trials investigating the effect of ALA supplementation on obesity measurements including weight, body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and fat mass (FM) were included. Two class and dose-response meta-analysis were performed to data analysis.

RESULTS

Totally, 18, 21 and 8 studies were included for the meta-analysis of ALA-weight, ALA-BMI, ALA-WC, respectively. In the two-class meta-analysis, ALA treatment significantly reduced weight (WMD: -2.29 kg, 95% CI: -2.98, 1.60, P < .01) and BMI (WMD: -0.49 kg/m² , 95% CI:-0.83,-0.15, P = .005) but no effect on WC (WMD: -2.57 cm, 95% CI: -8.91, 3.76; P = .426). While the dose-response meta-analysis revealed that the duration of ALA treatment is a significant factor affecting WC reduction (P_{non-linearity}  = .047). While no evidence of departure from linearity was observed for other variables; moreover, subgrouping also revealed that gender could be an important factor affecting the ALA impact on WC which was significant among women (WMD: -4.099; CI: -7.837, -0.361; P = .032).

CONCLUSION

According to our finding, ALA treatment significantly reduced BMI, weight in a two-class meta-analysis without evidence of departure from linearity in terms of dose or duration. While the association of ALA treatment on WC is dependent to the duration of the study. Although further trials evaluating the other obesity measurements specially central obesity will be helpful to infer a more reliable result.

The Beneficial Effects of Alpha Lipoic Acid Supplementation on Lp-PLA2 Mass and Its Distribution between HDL and apoB-Containing Lipoproteins in Type 2 Diabetic Patients: A Randomized, Double-Blind, Placebo-Controlled Trial

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a new specific vascular inflammation biomarker that is carried by the lipoproteins in the blood and plays a prominent role in the pathogenesis of atherosclerosis. Increased Lp-PLA2 levels and impaired Lp-PLA2 distribution across high-density lipoprotein (HDL) and non-HDL lipoproteins have been reported in diabetic patients, which is associated with the increase in cardiovascular disease (CVD) risk. This study is aimed at investigating the effect of alpha lipoic acid (ALA), as an antioxidant with potential cardioprotective properties, on the Lp-PLA2 mass and its distribution in diabetic patients. In a double-blind, randomized, placebo-controlled clinical trial, seventy diabetic patients were randomly allocated to ALA (1200 mg ALA as two 600 mg capsules/day) and placebo (two maltodextrin capsules/day) groups. The serum levels of total Lp-PLA2 mass, HDL-Lp-PLA2, oxidized low-density lipoproteins (ox-LDL), apolipoprotein A1 (apo A1), lipid profiles, fasting blood sugar (FBS), and insulin were measured, and apolipoprotein B- (apoB-) associated Lp-PLA2 and homeostasis model of assessment index (HOMA-IR) were calculated at the baseline and after 8 weeks of intervention. ALA significantly decreased the ox-LDL, total Lp-PLA2 mass, apoB-associated Lp-PLA2, and percent of apoB-associated Lp-PLA2 and triglyceride and increased the percent of HDL-Lp-PLA2 compared with the placebo group but had no significant effect on HDL-Lp-PLA2 mass, apo A1, lipid profiles, and glycemic indices. There was a positive correlation between the reduction in the ox-LDL level and total Lp-PLA2 mass in the ALA group. In conclusion, ALA may decrease the CVD risk by reducing the ox-LDL and Lp-PLA2 mass and improving the Lp-PLA2 distribution among lipoproteins in type 2 diabetic patients.

The Antioxidant Alpha-Lipoic Acid Inhibits Proliferation and Invasion of Human Gastric Cancer Cells via Suppression of STAT3-Mediated MUC4 Gene Expression

Background

Metastasis and invasion are the main causes of mortality in gastric cancer. To improve the treatment of gastric cancer, the development of effective and innovative antitumor agents toward invasion and proliferation is needed. Alpha-lipoic acid (ALA), a naturally occurring thiol antioxidant, showed antiproliferative and cytotoxic effects on several cancers. So it is feasible to explore whether ALA can be used to inhibit proliferation and invasion in human gastric cancer.

Methods

The expression of MUC4 in human gastric cancer tissues was assayed by immunohistochemistry. Then, we performed in vitro cell proliferation and invasion analysis to explore the antitumor effect of ALA using AGS, BGC-823, and MKN-28 cells. To further explore the mechanism of ALA-mediated downregulation of MUC4, we cotransfected human gastric cancer cells with STAT3 siRNA and STAT3 overexpression construct. ChIP assays were carried out to find the relationship between MUC4 and STAT3.

Results

We found that the MUC4 gene was strongly expressed in human gastric cancer tissues. Meanwhile, ALA reduced proliferation and invasion of human gastric cancer cells by suppressing MUC4 expression. We also found that STAT3 was involved in the inhibition of MUC4 by ALA. Mechanistically, ALA suppressed MUC4 expression by inhibiting STAT3 binding to the MUC4 promoter region.

Conclusion

ALA inhibits both proliferation and invasion of gastric cancer cells by suppression of STAT3-mediated MUC4 gene expression.

The Effect of Antioxidant Supplementation in Patients with Tinnitus and Normal Hearing or Hearing Loss: A Randomized, Double-Blind, Placebo Controlled Trial

Tinnitus is the perception of sound in the absence of any external stimulus. Oxidative stress is possibly involved in its pathogenesis and a variety of antioxidant compounds have been studied as potential treatment approaches. The objective of the present study was to assess the effects of antioxidant supplementation in tinnitus patients. This is a randomized, double-blind, placebo-controlled clinical trial. Patients (N = 70) were randomly allocated to antioxidant supplementation (N = 35) or to placebo (N = 35) for a total of 3 months. Demographic, anthropometric, clinical, and nutritional data were collected. Serum total antioxidant capacity (TAC), oxidized LDL (oxLDL), and superoxide dismutase (SOD), tinnitus loudness, frequency, and minimum masking level (MML), and scores in Tinnitus Handicap Inventory questionnaire (THI), Tinnitus Functional Index (TFI), and Visual Analogue Scale (VAS) were evaluated at baseline and follow-up. Tinnitus loudness and MML significantly decreased from baseline to post measure (p < 0.001) only in the antioxidant group, the overall change being significantly different between the two groups post-intervention (p < 0.001). THI and VAS decreased only in the antioxidant group. Differences in changes in serum TAC, SOD, and oxLDL post-intervention were insignificant. In conclusion, antioxidant therapy seems to reduce the subjective discomfort and tinnitus intensity in tinnitus patients.

Impact of Alpha-Lipoic Acid Chronic Discontinuous Treatment in Cardiometabolic Disorders and Oxidative Stress Induced by Fructose Intake in Rats

Insulin resistance (IR) and cardiometabolic disorders are the main consequences of today’s alimentary behavior. This study evaluates the effects of a chronic-discontinuous treatment with alpha-lipoic acid (AL), an antioxidant substance that improves glycemic control associated with diabetes mellitus, on metabolic disorders and plasma oxidative stress induced by fructose intake, in rats. Sprague-Dawley rats (48 animals) were randomized into two series (n = 24): rats fed with standard chow or with standard chow supplemented with 60% fructose. In each of the two series, for 2 weeks/month over 12 weeks, a group of rats (n = 12) was intraperitoneally injected with NaCl 0.9%, and a second group (n = 12) received AL 50 mg/kg/day. Body weight, glycemia, and systolic blood pressure were monitored throughout the study. After 12 weeks, IR, plasma lipoproteins, uric acid, transaminase activities, and oxidative stress markers were assessed. The high fructose-enriched diet induced cardiometabolic disorders (hypertension, hyperglycemia, IR and dyslipidemia), an increase in uric acid concentration, transaminase activities and C-reactive protein level. This diet also enhanced plasma products of lipid and protein oxidation, homocysteine level, and decreased GSH/GSSG ratio. In this field, there is evidence to indicate that oxidative stress plays an important role in the etiology of diabetic complications. AL discontinuous treatment prevents the metabolic disorders induced by fructose intake, reduced plasma lipid and protein oxidation-products, and restored the GHS/GSSG ratio. Our study proves a promising potential of the chronic-discontinuous treatment of AL and highlights the pleiotropic effects of this antioxidant substance in metabolic disorders such as diabetes.