Effect of DL- -Lipoic Acid on the Status of Lipid Peroxidation and Lipids in Aged Rats

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Role of lipoic acid in multiple sclerosis

Lipoic acid (LA) is an endogenous antioxidant that exists widely in nature. Supplementation with LA is a promising approach to improve the outcomes of patients with multiple sclerosis (MS). This systematic review aimed to provide a comprehensive overview of both in vitro and in vivo studies describing the pharmacokinetics, efficacy, safety, and mechanism of LA in MS‐related experiments and clinical trials. A total of 516 records were identified by searching five databases, including PubMed, Web of Science, Embase, Scopus, and Cochrane Library. Overall, we included 20 studies reporting LA effects in cell and mouse models of MS and 12 studies reporting LA effects in patients with MS. Briefly, cell experiments revealed that LA protected neurons by inhibiting the expression of inflammatory mediators and activities of immune cells. Experimental autoimmune encephalomyelitis mouse experiments demonstrated that LA consistently reduced the number of infiltrating immune cells in the central nervous system and decreased the clinical disability scores. Patients with MS showed relatively stable Expanded Disability Status Scale scores and better walking performance with few adverse events after the oral administration of LA. Notably, heterogeneity of this evidence existed among modeling methods, LA usage, MS stage, and trial duration. In conclusion, this review provides evidence for the anti‐inflammatory and antioxidative effects of LA in both in vitro and in vivo experiments; therefore, patients with MS may benefit from LA administration. Whether LA can be a routine supplementary therapy warrants further study.

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.

Lipoic acid-derived cross-linked liposomes for reduction-responsive delivery of anticancer drug

Liposomes have emerged as a fascinating nanocarriers for the delivery of cancer therapeutics. However, their efficacy for cancer therapy is reduced partially because of the serum-instability and incomplete drug release. In this study, a novel disulfide cross-linked liposomes (CLs) assembled from dimeric lipoic acid-derived glycerophosphorylcholine (di-LA-PC) conjugate was developed. The conjugate was synthesized by a facial esterification of lipoic acid (LA) and glycerophosphorylcholine (GPC) and characterized by MS, ¹H NMR and ¹³C NMR. Featuring the enhanced serum-stability and intracellular drug release determined by in vitro stability and GSH-responsive behavior, CLs prepared with dried thin film technique following 10 % dithiothreitol (DTT) cross-linking can attain effective delivery of anticancer candidates. Notably, CLs stably encapsulated doxorubicin (Dox) in their vesicular structures and showed a remarkable thiol-sensitive release of payload upon cellular uptake by cancer cells, compared to that of uncross-linked liposomes (uCLs) or Doxil-like liposome (DLLs). The cell viability and apoptosis of Dox-loaded CLs worked the pronounced cytotoxic effects to MCF-7 cells with an IC₅₀ value of 10.8 μg Dox equiv./mL comparable to free Dox and 2.8-fold higher than DLLs. More importantly, it is demonstrated that the nanoscale characteristics of Dox-loaded CLs could prevent the proliferation of adriamycin-resistant MCF-7/ADR cell line, highlighting their potential in reversal of drug resistance. Furthermore, the preliminary in vivo test (n = 3) showed that disulfide cross-linked liposomal formulation of Dox (Dox-CLs) improved the therapeutic efficacy compared to free Dox and DLLs in a human breast carcinoma xenograft mouse model. Therefore, the current thiol-responsive cross-linked liposome may provide a robust drug delivery platform for cancer therapy.

Effects of 12 Weeks of Essential Amino Acids (EAA)-Based Multi-Ingredient Nutritional Supplementation on Muscle Mass, Muscle Strength, Muscle Power and Fatigue in Healthy Elderly Subjects: A Randomized Controlled Double-Blind Study

OBJECTIVE

To counteract muscle mass, muscle strength and power loss during aging, and to study age-related change of neuromuscular manifestation of fatigue in relation to nutritional supplementation.

DESIGN

randomized controlled double-blind study.

SETTING

Twice-daily consumption for 12 weeks of an Essential Amino Acids (EAA)-based multi-ingredient nutritional supplement containing EAA, creatine, vitamin D and Muscle Restore Complex®.

PARTICIPANTS

38 healthy elderly subjects (8 male, 30 female; age: 68.91±4.60 years; body weight: 69.40±15.58 kg; height: 1.60±0.09 m) were randomized and allocated in supplement (SUPP) or placebo (PLA) group. Mean Measurements: Vitamin D blood level; Appendicular Lean Mass (ALM); Visceral Adipose Tissue (VAT); Maximal Voluntary Contraction (MVC) and Peak Power (PP); myoelectric descriptors of fatigue: Fractal Dimension and Conduction Velocity initial values (FD iv, CV iv), their rates of change (FD slopes, CV slopes) and the Time to perform the Task (TtT). Mean Results: Significant changes were found in SUPP compared to baseline: Vitamin D (+8.73 ng/ml; p<0.001); ALM (+0.34 kg; p<0.001); VAT (-76.25 g; p<0.001); MVC (+0.52 kg; p<0.001); PP (+4.82 W; p<0.001). Between group analysis (SUPP Vs. PLA) showed improvements: vitamin D blood levels (+11,72 ng/ml; p<0.001); Legs FFM (+443.7 g; p<0.05); ALM (+0.53 kg; p<0.05); MVC (+1.38 kg; p<0.05); PP (+9.87 W; p<0.05). No statistical changes were found for FD iv, CV iv, FD and CV slopes and TtT, either compared to baseline or between groups. Significant correlations between mean differences in SUPP group were also found.

CONCLUSION

The study demonstrates that in healthy elderly subjects an EAA-based multi-ingredient nutritional supplementation of 12 weeks is not effective to change myoelectric manifestation of fatigue and TtT failure but can positively affect muscle mass, muscle strength, muscle power and VAT, counterbalancing more than one year of age-related loss of muscle mass and strength.

α-Lipoic Acid Vaginal Administration Contrasts Inflammation and Preterm Delivery in Rats

α-Lipoic acid (ALA) is a safe natural molecule involved in the immunomodulation of many physiological processes. Orally administered ALA has been reported to treat several inflammatory pathologies and support pregnancy. Our study aimed at testing ALA vaginal administration in female Wistar rats evaluating its tissue distribution (experiment I), impact on implantation process (experiment II), and effectiveness in contrasting induced preterm birth (experiment III). In experiment I, rats were intravaginally treated with 50 mg/kg or 500 mg/kg ALA, or with a physiologic solution, for 4 days. α-Lipoic acid distribution in uterus and cervical tissues was evaluated by immunohistochemical analyses. In experiment II, rats received intravaginally the above treatments for 5 days, then they were mated and, if pregnant, included in the experiment to evaluate both implantation rate and the content of implantation mediators in uterus tissues. In experiment III, pregnant rats were pretreated with placebo or with vaginal ALA for 4 days and then induced to delivery with mifepristone plus PGE2 on the 19th day of pregnancy. The delivery time was recorded, and the messenger RNA (mRNA) levels of pro-inflammatory cytokines were detected in the uterine tissues by real-time polymerase chain reaction. Immunohistochemistry was also performed. Results showed that vaginal ALA was well absorbed and distributed. The treatment did not affect the implantation process and was able to significantly revert mifepristone plus prostaglandin E2 effects, delaying the timing of delivery and significantly decreasing mRNA synthesis and release of pro-inflammatory cytokines. We provide for the first time new information on vaginal ALA use, even during pregnancy, opening a perspective for further studies.

Alpha-Lipoic Acid Downregulates IL-1β and IL-6 by DNA Hypermethylation in SK-N-BE Neuroblastoma Cells

Alpha-lipoic acid (ALA) is a pleiotropic molecule with antioxidant and anti-inflammatory properties, of which the effects are exerted through the modulation of NF-kB. This nuclear factor, in fact, modulates different inflammatory cytokines, including IL-1b and IL-6, in different tissues and cell types. We recently showed that IL-1b and IL-6 DNA methylation is modulated in the brain of Alzheimer's disease patients, and that IL-1b expression is associated to DNA methylation in the brain of patients with tuberous sclerosis complex. These results prompted us to ask whether ALA-induced repression of IL-1b and IL-6 was dependent on DNA methylation. Therefore, we profiled DNA methylation in the 5'-flanking region of the two aforementioned genes in SK-N-BE human neuroblastoma cells cultured in presence of ALA 0.5 mM. Our experimental data pointed out that the two promoters are hypermethylated in cells supplemented with ALA, both at CpG and non-CpG sites. Moreover, the observed hypermethylation is associated with decreased mRNA expression and decreased cytokine release. These results reinforce previous findings indicating that IL-1b and IL-6 undergo DNA methylation-dependent modulation in neural models and pave the road to study the epigenetic mechanisms triggered by ALA.

Protective effects of alpha-lipoic Acid on oleic Acid-induced acute lung injury in rats

BACKGROUND

Oxidative stress is believed to be an important factor in the pathogenesis of acute lung injury (ALI).

AIMS

The aim of this study was to investigate the possible protective role of alpha-lipoic acid (α-LA) on oleic acid (OA)-induced ALI in rats.

STUDY DESIGN

Animal experiment.

METHODS

A total of thirty-five rats were divided into five groups in the study. Group 1 served as a control group. Rats in Group 2 (α-LA) were administered α-LA intraperitoneally at a dose of 100 mg/kg body weight (BW). Rats in Group 3 (OA) were administered OA intravenously at a dose of 100 mg/kg BW. In Group 4 (pre-OA-α-LA), α-LA was given 15 minutes prior to OA infusion, and in Group 5 (post-OA-α-LA), α-LA was given two hours after OA infusion. Four hours after the OA infusion, rats were decapitated. Blood samples were collected to measure serum levels of malondialdehyde (MDA) and glutathione (GSH), and the levels of activity for superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). Lung tissue samples were taken for histopathological examination.

RESULTS

Exposure to OA resulted in increases in serum MDA levels (p<0.001), as well as histopathological lesions in lung tissue, and decreases in CAT (p<0.05), GSH-Px (p<0.05) activities and GSH (p<0.05) levels. On the other hand, MDA levels were decreased significantly (p<0.001), while CAT (p<0.05), GSH-Px (p<0.01) activities and GSH (p<0.05) levels were increased significantly in the pre-OA-α-LA group compared with the OA group.

CONCLUSION

α-LA was found to lessen oxidative stress and to have positive effects on antioxidants in cases of OA-induced ALI. In conclusion, α-LA appears to have protective effects against ALI and potential for the prevention of ALI.

Effects of alpha-lipoic acid supplementation on inflammation, oxidative stress, and serum lipid profile levels in patients with end-stage renal disease on hemodialysis

OBJECTIVE

We examined the effects of alpha-lipoic acid (ALA) supplementation on inflammation, oxidative stress, and serum lipid profile levels in hemodialysis (HD) patients.

DESIGN

This was a double-blinded, randomized, placebo-controlled clinical trial.

SETTING

The present study involved HD centers in Tabriz, Iran.

PATIENTS

Participants included 63 patients with end-stage renal disease (43 men and 20 women; age range: 22-79 years) undergoing maintenance HD.

INTERVENTION

HD patients were randomly assigned into the supplemented group (n = 31), receiving a daily dose of ALA (600 mg), or a control group (n = 32), receiving placebo for 8 weeks.

MAIN OUTCOME MEASURES

High sensitivity C-reactive protein (hsCRP), malondialdehyde, total antioxidant status, total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured at baseline and after 8 weeks of supplementation.

RESULTS

At the end of intervention, 11 patients were excluded from the study. HsCRP levels decreased by 18.7% in the supplemented group after 8 weeks of supplementation, and the reduction was significant in comparison with the placebo group (P < .05); this finding was also significant after adjusting for baseline values of hsCRP. The mean malondialdehyde and total antioxidant status levels did not change significantly in the 2 groups during the study. The mean high-density lipoprotein cholesterol concentrations increased significantly in the supplemented group at the end of the study (P < .05); however, this improvement was not statistically significant as compared with the placebo group. No significant alterations were observed in the other lipid profile parameters within each group during the study.

CONCLUSION

ALA supplementation significantly reduced hsCRP levels, which is a risk factor for cardiovascular disease in HD patients.

Role of lipoic acid on insulin resistance and leptin in experimentally diabetic rats

OBJECTIVE

We aimed to examine the changes in serum insulin and leptin levels in induced type 1 diabetes mellitus in relationship to glycemic state and lipid profiles and to clarify the role of lipoic acid (LA).

METHODS

Ninety-six male rats were equally divided into the following: a control group (normal, nondiabetic), a diabetic group induced by subcutaneous injection of alloxan (non-LA-treated), and an LA-treated diabetic group (for 4 weeks). Body weight, serum lipid profile, glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), and leptin were measured.

RESULTS

This study showed a significant increase in serum triacylglycerol (TG), total cholesterol, glucose levels, and HOMA-IR and a significant decrease in body weight gain, insulin, and leptin levels in the diabetic group compared to the control group. LA treatment induced a significant decrease in glucose, TG, and total cholesterol levels and significantly increased serum insulin and leptin levels in comparison with the diabetic group.

CONCLUSION

Induced diabetes resulted in insulin resistance, hyperlipidemia, and hypoleptinemia, while LA ameliorates these changes and improves insulin sensitivity.

Dietary fructose accelerates the development of diabetes in UCD-T2DM rats: amelioration by the antioxidant, alpha-lipoic acid

Sustained fructose consumption has been shown to induce insulin resistance and glucose intolerance, in part, by promoting oxidative stress. Alpha-lipoic acid (LA) is an antioxidant with insulin-sensitizing activity. The effect of sustained fructose consumption (20% of energy) on the development of T2DM and the effects of daily LA supplementation in fructose-fed University of California, Davis-Type 2 diabetes mellitus (UCD-T2DM) rats, a model of polygenic obese T2DM, was investigated. At 2 mo of age, animals were divided into three groups: control, fructose, and fructose + LA (80 mg LA.kg body wt(-1).day(-1)). One subset was followed until diabetes onset, while another subset was euthanized at 4 mo of age for tissue collection. Monthly fasted blood samples were collected, and an intravenous glucose tolerance test (IVGTT) was performed. Fructose feeding accelerated diabetes onset by 2.6 +/- 0.5 mo compared with control (P < 0.01), without affecting body weight. LA supplementation delayed diabetes onset in fructose-fed animals by 1.0 +/- 0.7 mo (P < 0.05). Fructose consumption lowered the GSH/GSSG ratio, while LA attenuated the fructose-induced decrease of oxidative capacity. Insulin sensitivity, as assessed by IVGTT, decreased in both fructose-fed and fructose + LA-supplemented rats. However, glucose excursions in fructose-fed LA-supplemented animals were normalized to those of control via increased glucose-stimulated insulin secretion. Fasting plasma triglycerides were twofold higher in fructose-fed compared with control animals at 4 mo, and triglyceride exposure during IVGTT was increased in both the fructose and fructose + LA groups compared with control. In conclusion, dietary fructose accelerates the onset of T2DM in UCD-T2DM rats, and LA ameliorates the effects of fructose by improving glucose homeostasis, possibly by preserving beta-cell function.

Plasma protein oxidation in aging rats after alpha-lipoic acid administration

In the present study, we investigated whether alpha-lipoic acid administration could have prooxidant or antioxidant effect on oxidative protein damage parameters such as protein carbonyl, nitrotyrosine, advanced oxidation protein products, and protein thiol, as well as oxidative stress parameters such as total thiol, nonprotein thiol, and lipid hydroperoxide in the plasma proteins of aged rats. Alpha-lipoic acid (100 mg/kg body wt/day) was administrated intraperitoneally to the Sprague-Dawley rats for 14 days. Protein carbonyl, nitrotyrosine, and advanced oxidation protein products levels were increased, protein thiol, nonprotein thiol, and total thiol levels were not changed in the plasma proteins of aged rats with alpha-lipoic acid administration. In aging rats with and without alpha-lipoic acid administration, plasma lipid hydroperoxide levels were significantly increased compared with those of the control group. The increased levels of protein oxidation markers such as protein carbonyl, nitrotyrosine and advanced oxidation protein products in the plasma proteins of alpha-lipoic acid-administrated aged rats compared with nonadministrated aged rats suggests that protein oxidation is increased in alpha-lipoic acid-administrated aged rats. We assume that an explanation for our findings regarding alpha-lipoic acid administration on protein oxidation markers in the plasma proteins of aged rats may be due to the prooxidant effects of alpha-lipoic acid.

Prooxidant activities of alpha-lipoic acid on oxidative protein damage in the aging rat heart muscle

In the present study, we investigated whether alpha-lipoic acid (ALA) supplementation could have prooxidant or antioxidant effects on protein oxidation parameters such as protein carbonyl (PCO), nitrotyrosine (NT), advanced oxidation protein products (AOPP), and protein thiol (P-SH), as well as oxidative stress parameters such as total thiol (T-SH), non-protein thiol (Np-SH), and lipid hydroperoxide (LHP) in the heart muscle tissue of aged rats. ALA (100 mg/kg body wt/day) was administered intraperitoneally to the experimental animals for 14 days. PCO, NT, AOPP, and P-SH levels were increased, T-SH and Np-SH levels were not changed, and only LHP levels were decreased in the heart muscle tissue of aged rats with ALA supplementation. When compared with non-supplemented aged rats, increasing levels of protein oxidation markers such as PCO, NT, and AOPP in ALA-supplemented aged rats may suggest that oxidative protein damage is increased in ALA-supplemented aged rats. We assume that an explanation for our findings regarding ALA supplementation on protein oxidation markers in the heart muscle tissue of aged rats may be due to the prooxidant effects of ALA. The prooxidant effects of ALA supplementation should be considered in future studies.

Effect of alpha-lipoic acid supplementation on markers of protein oxidation in post-mitotic tissues of ageing rat

In the present study, we investigated whether DL-alpha-lipoic acid (LA) supplementation could have prooxidant or antioxidant effects on oxidative protein damage parameters such as protein carbonyl (PCO), nitrotyrosine (NT), advanced oxidation protein products (AOPP), and protein thiol (P-SH), as well as oxidative stress parameters such as total thiol (T-SH), non-protein thiol (Np-SH), and lipid hydroperoxide (LHP) in the brain and the skeletal muscle tissue of aged rats. PCO, and NT levels were increased, AOPP and P-SH levels were not changed in the brain tissue of aged rats given LA supplementation. On the other hand, TSH, Np-SH, and LHP levels were decreased in the brain tissue of aged rats given LA supplementation. The levels of the same parameters were not significantly different in the skeletal muscle tissue of aged rats given LA supplementation. The increased levels of protein oxidation markers such as PCO, and NT in the brain tissue of LA-supplemented aged rats compared with non-supplemented aged rats may suggest that oxidative protein damage is increased in LA-supplemented aged rats. We assume that an explanation for our findings regarding LA supplementation on protein oxidation markers in the brain tissue of aged rats may be due to the prooxidant effects of LA. Depending on post-mitotic tissue type and dosage of LA, the prooxidant effects of LA supplementation, should be considered in future studies.

Anti-aging medicine--the good, the bad, and the ugly

Complementary and alternative medicine has flourished since the beginning of time because of a human need to postpone the aging process and to reverse disease. Complementary and alternative medicine sells, because in some cases it works as well or better than mainstream medicine. In addition, many practitioners of complementary medicine understand Hippocrates' aphorism: "It is more important to know the person that has the disease than the disease the person has." It is important to recognize that spending time with the patient is often as therapeutic as drugs. CAM offers patients the time, touch, attention, and level of personal interaction that are increasingly uncommon in contemporary medical care. There is a major need for large and appropriately designed studies to test the effectiveness of complementary techniques. As in other areas of health care, studies in the elderly are consistently lacking. With the growing interest in CAM, it is important for medical providers to keep an open mind--to both the potential benefits and potential harms of alternative treatments. When treatments are shown to be dangerous or ineffective, we must educate the public and work to remove these therapies from the market place. When treatments are proven effective, Western and Eastern medical providers must work together with patients to provide the most appropriate and comprehensive health care.