alpha-Lipoic acid increases energy expenditure by enhancing adenosine monophosphate-activated protein kinase-peroxisome proliferator-activated receptor-gamma coactivator-1alpha signaling in the skeletal muscle of aged mice

Influence of maternal α-lipoic acid supplementation in Sprague Dawley rats on maternal and fetal metabolic health in pregnancies complicated by obesity

The objective of this study was to investigate the influence of α-lipoic acid (LA; R enantiomer) supplementation on maternal and fetal metabolic health in pregnancies complicated by maternal obesity. Forty female Sprague-Dawley rats were randomized to one of 4 treatment groups (n=10/group) throughout prepregnancy (3 weeks) and gestation (20 days): (1) a low calorie control (CON); (2) a high calorie obesity-inducing diet (HC); (3) the HC diet with 0.25% LA (HC+LA) or; (4) the HC diet pair-fed to match the caloric intake of the HC+LA group (HC+PF). On gestation day 20, pregnant rats were placed under anesthesia for collection of maternal/fetal blood and tissues. Compared with the HC group, LA-supplemented mothers demonstrated lower maternal prepregnancy and gestational weight gain (GWG), improved glycemic control (lower homeostatic model assessment for insulin resistance), and higher cholesterol concentrations in serum [high-density lipoprotein cholesterol (HDL-C) and low-and very-low density lipoprotein cholesterol (LDL/VLDL) fractions] and liver. Male and female fetuses from LA-supplemented mothers exhibited lower body weight, improved insulin sensitivity, and evidence of altered lipid metabolism including lower serum HDL-C, lower serum triglyceride (TG), and increased hepatic TG accumulation. Although maternal LA supplementation showed some benefit for both mothers and fetuses with respect to obesity and glycemic control, concern about the potential longer-term implications of liver cholesterol (mothers) and TG accumulation (fetuses) needs further investigation.

Stimulatory effect of dietary alpha-lipoic acid on growth performance, antioxidant capacity, liver enzymes, immunity and protection of African catfish, Clarias gariepinus (B.), Edwardsiella tarda infection

Edwardsiella tarda is one of the most common causes of fish diseases that hinder aquaculture. Oxidative stress in farm animals can induce a number of pathological disorders, production and general animal welfare. The use of exogenous dietary nonenzymatic antioxidants such as alpha-lipoic acid (ALA) can stop a pro-oxidant state and thus appears to have the potential to modulate the immune system and protect fish from bacterial infection. Thus, this study investigates the stimulatory effect of dietary ALA on growth performance, antioxidant capacity, liver enzymes, immunity and protection of African catfish, Clarias gariepinus (B.), against an infection with E. tarda. Five isonitrogenous and isocaloric diets (400 g/kg of crude protein) containing ALA at doses of 0.0 (control), 500, 1000, 1500 or 2000 mg/kg diet were served to 300 juveniles of African catfish (mean weight = 8.2 ± 0.2 g) adequately thrice per day for 12 weeks. Thereafter, 0.1 mL of E. tarda (ATCC 15947; 1.0 × 108  CFU/mL) was intraperitoneally injected into 10 fish from each tank and was monitored for 14 days. The results showed that ALA-fortified diets significantly boosted the fish growth, feed consumption and utilization and feed conversion ratio but no did not affect fish survival rate. The highest final fish weight (g), weight growth (g) and weight gain (%) were all considerably higher in fish fed with ALA-fortified diets (p < 0.05), especially from 1000 to 200 mg/kg ALA than the control group. Also, an enhanced hemato-biochemical, antioxidant and immune indices were noticed in African catfish-fed ALA-enriched diets. In a dose-dependent order, the levels of haematological indices such Ht, Hb, RBCs, WBCs and platelets were markedly increased (p < 0.05). Additionally, fish fed with ALA-based diets showed substantial (p < 0.05) declines in aspartate and alanine aminotransferase values, with the lowest values being found in the 2000 mg/kg diet while control group had highest values. Further, African catfish fed the feed fortified with 2000 mg ALA/kg diet showed the highest levels of lysozyme, respiratory burst, proteases and esterase activities (p < 0.05). Following exposure of fish to E. tarda infection, a significant reduction in the mortality was obtained in African catfish fed with ALA-based diets, especially from 1500 to 2000 mg ALA/kg diet (3.3%); while fish fed with the control diet had highest mortality (86.7%). Therefore, diets supplemented with ALA evoked fish growth performance, antioxidants and nonspecific immunity of African catfish. Also, resistance of African catfish to E. Tarda infection were raised when fed ALA-fortified diets at optimum inclusion rate of 1300 mg ALA/kg diet.

The immunosuppressive, growth-hindering, hepatotoxic, and oxidative stress and immune related-gene expressions-altering effects of gibberellic acid in Oreochromis niloticus: A mitigation trial using alpha-lipoic acid

This study aimed to examine the effects of gibberellic acid (GBA) on growth, hemato-biochemical parameters related to liver functions, digestive enzymes, and immunological response in Oreochromis niloticus. Besides, the probable underlying mechanisms were explored by assessing antioxidant, apoptotic, and immune-related gene expression. Furthermore, the likelihood of restoration following alpha-lipoic acid (LIP) dietary supplementation was explored. The fish (average initial weight 30.75 ± 0.46) were equally classified into four groups: the control group, the LIP group (fed on a basal diet plus 600 mg/kg of LIP), the GBA group (exposed to 150 mg GBA/L), and the GBA + LIP group (exposed to 150 mg GBA/L and fed a diet containing LIP and GBA) for 60 days. The study findings showed that LIP supplementation significantly reduced GBA's harmful effects on survival rate, growth, feed intake, digestive enzymes, and antioxidant balance. Moreover, the GBA exposure significantly increased liver enzymes, stress markers, cholesterol, and triglyceride levels, all of which were effectively mitigated by the supplementation of LIP. Additionally, LIP addition to fish diets significantly minimized the histopathological alterations in the livers of GBA-treated fish, including fatty change, sharply clear cytoplasm with nuclear displacement to the cell periphery, single-cell necrosis, vascular congestion, and intralobular hemorrhages. The GBA-induced reduction in lysozyme activity, complement C3, and nitric oxide levels, together with the downregulation of antioxidant genes (cat and sod), was significantly restored by dietary LIP. Meanwhile, adding LIP to the GBA-exposed fish diets significantly corrected the aberrant expression of hsp70, caspase- 3, P53, pcna, tnf-a, and il-1β in O. niloticus liver. Conclusively, dietary LIP supplementation could mitigate the harmful effects of GBA exposure on fish growth and performance, physiological conditions, innate immunity, antioxidant capability, inflammatory response, and cell apoptosis.

Synergistic effects of punicic acid and alpha lipoic acid ameliorate inflammatory and metabolic genes expression in C2C12 myoblast cells under oxidative stress condition

Inflammation is a reaction of the immune system to infection and injury; in fact, it positioned at the center of metabolic disorders, particularly obesity, type 2 diabetes, and cardiovascular diseases. Thus play a major role not only in their development, but also exerts as a crucial linking factor among those diseases. In this regard, one of the strategies for tackling this problem is application of antioxidants to treat such diseases. The present study was performed to evaluate the synergistic effects of punicic acid (PUA) and alpha-lipoic acid (ALA) as antioxidants and radical scavenging reagents on the expression of some inflammatory and metabolism-related genes under oxidative stress in the muscle cells. The experimental treatments consisted of a range of 20, 40, 80, 160, and 320 µM of PUA, and 5, 25, 50, 100, and 200 µM of ALA with a 200 µM concentration of H2 O2 as an oxidative stress inducer. Accordingly, fatty acid treatments were applied for 24 h, and H2 O2 was treated for 1 h. Our results indicated that the simultaneous treatment of PUA and ALA at optimal concentrations (80 and 50 µM, respectively) decreased the expression of inflammation genes and increased the expression of regulatory genes (Pparγ, Pgc-1α) related to metabolism (p < .05). Unexpectedly, H2 O2 treatment increased the Fndc5 expression (p < .05). Maximal upregulation of Pparγ, Pgc-1α were obtained when fatty acids combination (PUA and ALA) were used in the culture of H2 O2 treated cells (p < .05). Therefore, our findings suggest that the simultaneous use of PUA and ALA fatty acids could reduce oxidative stress, and the expression of inflammatory genes, thereby improving the cell metabolism.

(+)-Lipoic Acid Reduces Lipotoxicity and Regulates Mitochondrial Homeostasis and Energy Balance in an In Vitro Model of Liver Steatosis

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of lipids within hepatocytes, which compromises liver functionality following mitochondrial dysfunction and increased production of reactive oxygen species (ROS). Lipoic acid is one of the prosthetic groups of the pyruvate dehydrogenase complex also known for its ability to confer protection from oxidative damage because of its antioxidant properties. In this study, we aimed to investigate the effects of lipoic acid on lipotoxicity and mitochondrial dynamics in an in vitro model of liver steatosis. HepG2 cells were treated with palmitic acid and oleic acid (1:2) to induce steatosis, without and with 1 and 5 µM lipoic acid. Following treatments, cell proliferation and lipid droplets accumulation were evaluated. Mitochondrial functions were assessed through the evaluation of membrane potential, MitoTracker Red staining, expression of genes of the mitochondrial quality control, and analysis of energy metabolism by HPLC and Seahorse. We showed that lipoic acid treatment restored membrane potential to values comparable to control cells, as well as protected cells from mitochondrial fragmentation following PA:OA treatment. Furthermore, our data showed that lipoic acid was able to determine an increase in the expression of mitochondrial fusion genes and a decrease in mitochondrial fission genes, as well as to restore the bioenergetics of cells after treatment with palmitic acid and oleic acid. In conclusion, our data suggest that lipoic acid reduces lipotoxicity and improves mitochondrial functions in an in vitro model of steatosis, thus providing a potentially valuable pharmacological tool for NAFLD treatment.

Neuroprotective Efficacy of a Nanomicellar Complex of Carnosine and Lipoic Acid in a Rat Model of Rotenone-Induced Parkinson's Disease

Oxidative stress, accompanied by mitochondrial dysfunction, is a key mechanism involved in the pathogenesis of Parkinson's disease (PD). Both carnosine and lipoic acid are potent antioxidants, the applicability of which in therapy is hindered by their limited bioavailability. This study aimed to evaluate the neuroprotective properties of a nanomicellar complex of carnosine and lipoic acid (CLA) in a rotenone-induced rat model of PD. Parkinsonism was induced via the administration of 2 mg/kg rotenone over the course of 18 days. Two doses of intraperitoneal CLA (25 mg/kg and 50 mg/kg) were administered alongside rotenone to assess its neuroprotective effect. At 25 mg/kg CLA decreased muscle rigidity and partially restored locomotor activity in animals that received rotenone. Furthermore, it caused an overall increase in brain tissue antioxidant activity, accompanied by a 19% increase in neuron density in the substantia nigra and increased dopamine levels in the striatum relative to animals that only received rotenone. Based on the acquired results, it may be concluded that CLA have neuroprotective properties and could potentially be beneficial in PD treatment when used in conjunction with the base therapy.

Clinical effectiveness of α-lipoic acid, myo-inositol and propolis supplementation on metabolic profiles and liver function in obese patients with NAFLD: A randomized controlled clinical trial

BACKGROUND

To compare the effects of α-lipoic acid (ALA), myo-inositol (MI) and propolis supplementation on metabolic parameters and liver function in obese patients with non-alcoholic fatty liver disease (NAFLD) METHODS: Ninety-two obese patients with NAFLD were randomly allocated into one of the four groups (ALA, MI, propolis, and control groups) for 8 weeks. At pre-and post-intervention, anthropometric measures, metabolic parameters and liver function were assessed. Clinical effectiveness was assessed using Absolute Risk Reduction (ARR) and Number Needed to Treat (NNT).

RESULTS

After 8 weeks, apart from waist-to-hip ratio, all studied anthropometric measures decreased significantly in each of the groups over the trial. Although the greatest improvements in glycemic indices were observed in MI group (p < 0.05), the differences among the groups were not significant. Control group showed the greatest reduction in serum triglyceride level (p = 0.026) while the greatest improvements in serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were observed in MI group (p = 0.043, p = 0.019 and p = 0.041, respectively). Alanine aminotransferase (ALT) levels reduced significantly in all groups, particularly in propolis group (p = 0.012). The greatest reduction in serum aspartate transaminase (AST) level was observed in control group (p < 0.001), however, the difference among the groups was statistically marginal (p = 0.058). The estimated NNTs for one grade reduction in liver steatosis for MI, ALA and propolis supplementation compared with control group were 1.5, 2.2 and 3, respectively.

CONCLUSION

Dietary recommendation for weight loss accompanied by MI and then ALA supplementation improved metabolic parameters and liver steatosis. "Registered under ClinicalTrials.gov Identifier no: IRCT20100209003320N22".

Turning Back the Clock: A Retrospective Single-Blind Study on Brain Age Change in Response to Nutraceuticals Supplementation vs. Lifestyle Modifications

BACKGROUND

There is a growing consensus that chronological age (CA) is not an accurate indicator of the aging process and that biological age (BA) instead is a better measure of an individual's risk of age-related outcomes and a more accurate predictor of mortality than actual CA. In this context, BA measures the "true" age, which is an integrated result of an individual's level of damage accumulation across all levels of biological organization, along with preserved resources. The BA is plastic and depends upon epigenetics. Brain state is an important factor contributing to health- and lifespan.

METHODS AND OBJECTIVE

Quantitative electroencephalography (qEEG)-derived brain BA (BBA) is a suitable and promising measure of brain aging. In the present study, we aimed to show that BBA can be decelerated or even reversed in humans (N = 89) by using customized programs of nutraceutical compounds or lifestyle changes (mean duration = 13 months).

RESULTS

We observed that BBA was younger than CA in both groups at the end of the intervention. Furthermore, the BBA of the participants in the nutraceuticals group was 2.83 years younger at the endpoint of the intervention compared with their BBA score at the beginning of the intervention, while the BBA of the participants in the lifestyle group was only 0.02 years younger at the end of the intervention. These results were accompanied by improvements in mental-physical health comorbidities in both groups. The pre-intervention BBA score and the sex of the participants were considered confounding factors and analyzed separately.

CONCLUSIONS

Overall, the obtained results support the feasibility of the goal of this study and also provide the first robust evidence that halting and reversal of brain aging are possible in humans within a reasonable (practical) timeframe of approximately one year.

The effects of lipoic acid on respiratory diseases

Respiratory diseases, including lung cancer, pulmonary fibrosis, asthma, and the recently emerging fatal coronavirus disease-19 (COVID-19), are the leading causes of illness and death worldwide. The increasing incidence and mortality rates have attracted much attention to the prevention and treatment of these conditions. Lipoic acid (LA), a naturally occurring organosulfur compound, is not only essential for mitochondrial aerobic metabolism but also shows therapeutic potential via certain pharmacological effects (e.g., antioxidative and anti-inflammatory effects). In recent years, accumulating evidence (animal experiments and in vitro studies) has suggested a role of LA in ameliorating many respiratory diseases (e.g., lung cancer, fibrosis, asthma, acute lung injury and smoking-induced lung injury). Therefore, this review will provide an overview of the present investigational evidence on the therapeutic effect of LA against respiratory diseases in vitro and in vivo. We also summarize the corresponding mechanisms of action to inspire further basic studies and clinical trials to confirm the health benefits of LA in the context of respiratory diseases.

Effects of Dietary Alpha-Lipoic Acid on Growth Performance, Serum Biochemical Indexes, Liver Antioxidant Capacity and Transcriptome of Juvenile Hybrid Grouper (Epinephelus fuscoguttatus♀ × Epinephelus polyphekadion♂)

We aimed to investigate the effects of dietary alpha-lipoic acid (α-LA) on the growth performance, serum biochemical indexes, liver morphology, antioxidant capacity, and transcriptome of juvenile hybrid groupers (Epinephelus fuscoguttatus♀ × Epinephelus polyphekadion♂). Four experimental diets supplemented with 0 (SL0), 0.4 (L1), 0.6 (L2), and 1.2 (L3) g/kg α-LA were formulated and fed to three replicates of juvenile hybrid grouper (24.06 ± 0.15 g) for 56 d. The results indicated that dietary 0.4 and 0.6 g/kg α-LA significantly decreased the weight gain rate in juvenile hybrid groupers. Compared with SL0, the content of total protein in the serum of L1, L2, and L3 increased significantly, and alanine aminotransferase decreased significantly. The content of albumin in the serum of L3 increased significantly, and triglyceride, total cholesterol, and aspartate aminotransferase decreased significantly. In addition, the hepatocyte morphology in L1, L2, and L3 all showed varying degrees of improvement, and the activities of glutathione peroxidase and superoxide dismutase in the liver of L2 and L3 were significantly increased. A total of 42 differentially expressed genes were screened in the transcriptome data. KEGG showed that a total of 12 pathways were significantly enriched, including the pathway related to immune function and glucose homeostasis. The expression of genes (ifnk, prl4a1, prl3b1, and ctsl) related to immune were significantly up-regulated, and the expressions of gapdh and eno1 genes related to glucose homeostasis were significantly down-regulated and up-regulated, respectively. In summary, dietary supplementation of 0.4 and 0.6 g/kg α-LA inhibited the growth performance of juvenile hybrid groupers. A total of 1.2 g/kg α-LA could reduce the blood lipid level, improve hepatocyte damage, and increase the hepatic antioxidant enzyme activity. Dietary α-LA significantly affected the pathway related to immune function and glucose homeostasis.

Genomics as a Clinical Decision Support Tool for Identifying and Addressing Modifiable Causes of Cognitive Decline and Improving Outcomes: Proof of Concept Support for This Personalized Medicine Strategy

The landscape of therapeutics for mild cognitive impairment and dementia is quite limited. While many single-agent trials of pharmaceuticals have been conducted, these trials have repeatedly been unable to show improvement in cognition. It is hypothesized that because Alzheimer’s, like many other chronic illnesses, is not a monogenic illness, but is instead caused by the downstream effects of an individual’s genetic variants interacting with each other, the environment, and lifestyle, that improving outcomes will require a personalized, precision medicine approach. This approach requires identifying and then addressing contributing genomic and other factors specific to each individual in a simultaneous fashion. Until recently, the utility of genomics as part of clinical decision-making for Alzheimer’s and cognitive decline has been limited by the lack of availability of a genomic platform designed specifically to evaluate factors contributing to cognitive decline and how to respond to these factors The clinical decision support (CDS) platform used in the cases presented focuses on common variants that relate to topics including, but not limited to brain inflammation, amyloid processing, nutrient carriers, brain ischemia, oxidative stress, and detoxification pathways. Potential interventions based on the scientific literature were included in the CDS, but the final decision on what interventions to apply were chosen by each patient’s physician. Interventions included supplements with “generally regarded as safe (GRAS)” rating, along with targeted diet and lifestyle modifications. We hypothesize that a personalized genomically targeted approach can improve outcomes for individuals with mild cognitive impairment who are at high risk of Alzheimer’s. The cases presented in this report represent a subset of cases from three physicians’ offices and are meant to provide initial proof of concept data demonstrating the efficacy of this method and provide support for this hypothesis. These patients were at elevated risk for Alzheimer’s due to their apolipoprotein E ε4 status. While further prospective and controlled trials need to be done, initial case reports are encouraging and lend support to this hypothesis of the benefit of a genomically targeted personalized medicine approach to improve outcomes in individuals with cognitive decline who are at high risk for Alzheimer’s.

Lipoic acid prevents mirtazapine-induced weight gain in mice without impairs its antidepressant-like action in a neuroendocrine model of depression

Mirtazapine (MIRT) is a multi-target antidepressant used in treatment of severe depression with promising efficacy, but also with important side effects, mainly sedation and weight gain. Thus, the present study aimed to test the effects of the neuroprotective antioxidant lipoic acid (ALA) in the reversal of weight and metabolic changes induced by MIRT in corticosterone-induced depression model in mice, as well as proposed mechanisms for their association antidepressant and pro-cognitive effects. To do these male Swiss mice received Tween 80 (control), corticosterone (CORT 20 mg / kg), MIRT (3 mg / kg) and ALA (100 or 200 mg / kg), alone or associated for 21 days. After this, the animals were subjected to behavioral tests for affective and cognitive domains. Daily weight changes, blood cholesterol fractions and corticosterone were measured. Also, hippocampus (HC) protein expression of the serotonin transporter (SERT), synaptophysin, protein kinase B-Akt (total and phosphorylated) and the cytokines IL-4 and IL-6 were investigated. CORT induced a marked depression-like behavior, memory deficits, metabolic changes (total cholesterol and LDL) and increased serum corticosterone. Also, CORT increased SERT expression in the HC. MIRT alone or combined with ALA sustained its antidepressant-like effect, as well as reversed CORT-induced impairment in spatial recognition memory. Additionally, the association MIRT+ALA200 reversed the weight gain induced by the former antidepressant, as well as reduced serum corticosterone levels and SERT expression in the HC. ALA alone induced significant weight loss and reduced total cholesterol and HDL fraction. Our findings provide promising evidence about the ALA potential to prevent metabolic and weight changes associated to MIRT, without impair its antidepressant and pro-cognition actions. Therefore, ALA+MIRT combination could represent a new therapeutic strategy for treating depression with less side effects.

Effect of alpha-lipoic acid on arterial stiffness parameters in type 2 diabetes mellitus patients with cardiac autonomic neuropathy

Objective. Significantly underdiagnosed, diabetes-associated cardiac autonomic neuropathy (CAN) causes a wide range of cardiac disorders that may cause life-threatening outcomes. This study investigated the effects of alpha-lipoic acid (ALA) on arterial stiffness and insulin resistance (IR) parameters in type 2 diabetes mellitus (T2D) patients and definite CAN. Methods. A total of 36 patients with T2D and a definite stage of CAN were recruited. This investigation was carried out on two separate arms: traditional hypoglycemic therapy (n=18, control) and ALA (n=18) 600 mg in film-coated tablets/q.d. in addition to traditional hypoglycemic therapy. The duration of the study was three months. Results. In subjects with T2D and definite stage of СAN, treatment with ALA resulted in a significant decrease of glucose, immunoreactive insulin concentration, and Homeostasis Model Assessment (HOMA)-IR (HOMA-IR) parameters; pulse wave velocity (PWV), aorta augmentation index (AIxao) during the active period of the day and decrease of PWV, AIxao, and brachial augmentation index during the passive period of the day compared with the results, obtained in the control group. Therefore, the administration of ALA to patients with T2D for three months promotes the improvement of glucose metabolism and arterial stiffness parameters. Conclusions. In patients with T2D and definite stage of СAN treatment with ALA improved HOMA-IR and arterial stiffness parameters. These findings can be of clinical significance for the complex treatment of diabetes-associated CAN.

Nutritional Supplements and Complementary Therapies in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) affects 1 in 5 women of reproductive age, and is characterized by menstrual irregularities, clinical or biochemical hyperandrogenism, and the presence of polycystic ovary morphology. One of the recommended treatment strategies in the international evidence-based guidelines is lifestyle modification, which includes diet and exercise, with the aim of improving a range of health outcomes. The incurable nature of PCOS reinforces the importance of developing novel and innovative symptomatic relief strategies, which are currently the only available approaches for improving quality of life for these women. Women with PCOS tend to be nutrient deficient in many common vitamins and minerals, thought to be associated with the psychological (depression, anxiety, etc.) and physiological (insulin resistance, diabetes, infertility, etc.) sequelae of the condition. Nutrient supplementation and the integration of complementary medicine as adjuncts to traditional lifestyle-based therapies in PCOS could therefore provide additional benefits to these women. In this review, we synthesize the evidence regarding nutrient supplementation and complementary therapies in PCOS, predominantly from randomized controlled trials, systematic reviews, and meta-analyses, to provide an overview of the state of knowledge in this field. The evidence to date suggests that specific vitamins (B-12, inositols, folate, vitamins D, E, and K), vitamin-like nutrients (bioflavonoids and α-lipoic acid), minerals (calcium, zinc, selenium, and chromium picolinate), and other formulations (melatonin, ω-3 fatty acids, probiotics, and cinnamon), as well as some complementary approaches such as acupuncture and yoga may be beneficial in PCOS. However, there remain areas of uncertainty and key limitations in the literature that must be overcome before these therapies can be integrated into routine clinical practice.

Long-Term Alpha-Lipoic Acid (ALA) Antioxidant Therapy Reduces Damage in the Cardiovascular System of Streptozotocin-Induced Diabetic Rats

Cellular damage, lipid oxidation and the action of inflammatory cytokines are implicated in the evolution of vascular complications associated with diabetes mellitus (DM) hyperglycemia. In contrast, alpha-lipoic acid (ALA) is a supplement with antioxidant and anti-inflammatory effects. This study aims to evaluate the overall effects of ALA supplementation by assessing its long-term systemic action on the vascular morphology of rats with induced diabetes. A total of 28 male rats were divided into 4 groups with seven animals each. For diabetes induction, two groups received streptozotocin. The animals in the lipoic and diabetic lipoic groups received ALA supplement. After 8 weeks the animals were anesthetized and blood collected was for hematological, biochemical and serological analyses. The thoracic aorta was removed, processed for paraffin and histological sections were stained for morphometric analysis. In diabetic groups, an improvement in hematological profile was observed, with platelet reduction in the diabetic lipoic group. ALA addition to the diet attenuated the negative effects in lipid profile; moreover, renal, hepatic and inflammatory parameters reduced or displayed values close to the values of the normal control. The anti-inflammatory effect of ALA was observed in diabetic animals, with a reduction of inflammatory citokines, accompanied by the improvement of morphological parameters in the aorta. In conclusion, long-term supplementation with ALA promoted systemic improvement, thus reducing the risk of vascular diseases. The changes in the renal and hepatic parameters without any negative impact in the hematological profile also show that ALA can be indicated as a low-risk prophylaxis or complementary therapy.

A spotlight on underlying the mechanism of AMPK in diabetes complications

OBJECTIVE

Type 2 diabetes (T2D) is one of the centenarian metabolic disorders and is considered as a stellar and leading health issue worldwide. According to the International Diabetes Federation (IDF) Diabetes Atlas and National Diabetes Statistics, the number of diabetic patients will increase at an exponential rate from 463 to 700 million by the year 2045. Thus, there is a great need for therapies targeting functions that can help in maintaining the homeostasis of glucose levels and improving insulin sensitivity. 5' adenosine monophosphate-activated protein kinase (AMPK) activation, by various direct and indirect factors, might help to overcome the hurdles (like insulin resistance) associated with the conventional approach.

MATERIALS AND RESULTS

A thorough review and analysis was conducted using various database including MEDLINE and EMBASE databases, with Google scholar using various keywords. This extensive review concluded that various drugs (plant-based, synthetic indirect/direct activators) are available, showing tremendous potential in maintaining the homeostasis of glucose and lipid metabolism, without causing insulin resistance, and improving insulin sensitivity. Moreover, these drugs have an effect against diabetes and are therapeutically beneficial in the treatment of diabetes-associated complications (neuropathy and nephropathy) via mechanism involving inhibition of nuclear translocation of SMAD4 (SMAD family member) expression and association with peripheral nociceptive neurons mediated by AMPK.

CONCLUSION

From the available information, it may be concluded that various indirect/direct activators show tremendous potential in maintaining the homeostasis of glucose and lipid metabolism, without resulting in insulin resistance, and may improve insulin sensitivity, as well. Therefore, in a nut shell, it may be concluded that the regulation of APMK functions by various direct/indirect activators may bring promising results. These activators may emerge as a novel therapy in diabetes and its associated complications.

Alpha-Lipoic Acid Is an Effective Nutritive Antioxidant for Healthy Adult Dogs

This study was designed to determine the effect of alpha-lipoic acid on the glutathione status in healthy adult dogs. Following a 15 month baseline period during which dogs were fed a food containing no alpha-lipoic acid, dogs were randomly allocated into four groups. Groups were then fed a nutritionally complete and balanced food with either 0, 75, 150 or 300 ppm of alpha-lipoic acid added for 6 months. Evaluations included physical examination, body weight, food intake, hematology, serum biochemistry profile and measurements of glutathione in plasma and erythrocyte lysates. Throughout, blood parameters remained within reference ranges, dogs were healthy and body weight did not change significantly. A significant increase of 0.05 ng/mL of total glutathione in red blood cell (RBC) lysate for each 1 mg/kg bodyweight/day increase in a-LA intake was observed. In addition, a significant increase was observed for GSH, GSSG and total glutathione in RBC lysate at Month 6. We conclude that alpha-lipoic acid, as part of a complete and balanced food, was associated with increasing glutathione activity in healthy adult dogs.

Impacts of Selected Dietary Nutrient Intakes on Skeletal Muscle Insulin Sensitivity and Applications to Early Prevention of Type 2 Diabetes

As the largest tissue in the body, skeletal muscle not only plays key roles in movement and glucose uptake and utilization but also mediates insulin sensitivity in the body by myokines. Insulin resistance in the skeletal muscle is a major feature of type 2 diabetes (T2D). A weakened response to insulin could lead to muscle mass loss and dysfunction. Increasing evidence in skeletal muscle cells, rodents, nonhuman primates, and humans has shown that restriction of caloric or protein intake positively mediates insulin sensitivity. Restriction of essential or nonessential amino acids was reported to facilitate glucose utilization and regulate protein turnover in skeletal muscle under certain conditions. Furthermore, some minerals, such as zinc, chromium, vitamins, and some natural phytochemicals such as curcumin, resveratrol, berberine, astragalus polysaccharide, emodin, and genistein, have been shown recently to protect skeletal muscle cells, mice, or humans with or without diabetes from insulin resistance. In this review, we discuss the roles of nutritional interventions in the regulation of skeletal muscle insulin sensitivity. A comprehensive understanding of the nutritional regulation of insulin signaling would contribute to the development of tools and treatment programs for improving skeletal muscle health and for preventing T2D.

Maternal intake of alpha-lipoic acid prevents development of symptoms associated with a fructose-rich diet in the male offspring in Wistar rats

The hypothesis was that maternal intake of the antioxidant alpha-lipoid acid (ALA), during the developmental period of the hypothalamic orexigenic neurons, causes a permanent beneficial effect in offspring metabolism. Pregnant Wistar rats were fed with standard diet (food) + ALA (0.4% wt/wt) from day 14 of gestation to day 20 of lactation (n = 4) or food (n = 4). At 3 months of age, male offspring born from ALA-fed rats or controls (CT) were randomly assigned to be fed with food + 10% fructose solution in drinking water (F) or food + tap water (C), resulting in four groups: ALAF, ALAC, CTF, and CTC (n = 5/group). Food intake and body weight (BW) were measured twice a week for 31 days. Metabolites' levels in blood, mRNA expressions of Npy, Agrp (hypothalamus), Fasn, Srebf1, Ppard, and Pparg (liver), and the antioxidant capacity of the liver were determined. Results significance was set at p < 0.05. Average BW gain, daily BW gain, and intraabdominal fat tissue at necropsy were higher in CTF group followed by CTC, ALAF, and ALAC groups. There were no differences between groups in Kcal intake per day. mRNA expressions of hypothalamic and hepatic genes and plasmatic levels of glucose and triglycerides were higher in CTF group followed by ALAF, CTC, and ALAC groups. Fructose intake affected the oxidative capacity of the liver, but this effect was not observed in the ALAF group. In conclusion, maternal ALA intake protected the adult offspring to develop metabolic symptoms associated with high fructose in the drinking water.

Alpha lipoic acid attenuates ER stress and improves glucose uptake through DNAJB3 cochaperone

Persistent ER stress, mitochondrial dysfunction and failure of the heat shock response (HSR) are fundamental hallmarks of insulin resistance (IR); one of the early core metabolic aberrations that leads to type 2 diabetes (T2D). The antioxidant α-lipoic acid (ALA) has been shown to attenuate metabolic stress and improve insulin sensitivity in part through activation of the heat shock response (HSR). However, these studies have been focused on a subset of heat shock proteins (HSPs). In the current investigation, we assessed whether ALA has an effect on modulating the expression of DNAJB3/HSP40 cochaperone; a potential therapeutic target with a novel role in mitigating metabolic stress and promoting insulin signaling. Treatment of C2C12 cells with 0.3 mM of ALA triggers a significant increase in the expression of DNAJB3 mRNA and protein. A similar increase in DNAJB3 mRNA was also observed in HepG2 cells. We next investigated the significance of such activation on endoplasmic reticulum (ER) stress and glucose uptake. ALA pre-treatment significantly reduced the expression of ER stress markers namely, GRP78, XBP1, sXBP1 and ATF4 in response to tunicamycin. In functional assays, ALA treatment abrogated significantly the tunicamycin-mediated transcriptional activation of ATF6 while it enhanced the insulin-stimulated glucose uptake and Glut4 translocation. Silencing the expression of DNAJB3 but not HSP72 abolished the protective effect of ALA on tunicamycin-induced ER stress, suggesting thus that DNAJB3 is a key mediator of ALA-alleviated tunicamycin-induced ER stress. Furthermore, the effect of ALA on insulin-stimulated glucose uptake is significantly reduced in C2C12 and HepG2 cells transfected with DNAJB3 siRNA. In summary, our results are supportive of an essential role of DNAJB3 as a molecular target through which ALA alleviates ER stress and improves glucose uptake.

Systemic effect of dietary lipid levels and α-lipoic acid supplementation on nutritional metabolism in zebrafish (Danio rerio): focusing on the transcriptional level

Considering the excessive lipid accumulation status caused by the increased dietary lipid intake in farmed fish, this study aimed to investigate the systemic effect of dietary lipid levels and α-lipoic acid supplementation on nutritional metabolism in zebrafish. A total of 540 male zebrafish (0.17 g) were fed with normal (CT) and high lipid level (HL) diets for 6 weeks, then fed on 1000 mg/kg α-lipoic acid supplementation diets for the second 6 weeks. HL diets did not affect whole fish protein content, but increased ASNS expression (P < 0.05). Dietary α-lipoic acid increased whole fish protein content, and decreased the expressions of protein catabolism-related genes in muscle of high lipid level groups (P < 0.05). Furthermore, HL diets increased the whole fish lipid content and the expressions of gluconeogenesis and lipogenesis-related genes (P < 0.05), and α-lipoic acid counteracted these effects and decreased the whole fish triglyceride and cholesterol contents and expressions of lipogenesis-related genes, with the enhanced expressions of lipolytic genes, especially in high lipid groups (P < 0.05). HL diets did not affect hepatocyte mitochondrial quantity or the mRNA expressions of mitochondrial biogenesis and electron transport chain-related genes; they were significantly increased by dietary α-lipoic acid (P < 0.05). These results indicated that high dietary lipid promotes lipid accumulation, while α-lipoic acid increases protein content in association of enhanced lipid catabolism. Thus, dietary α-lipoic acid supplementation could reduce lipid accumulation under high lipid, which provides a promising new approach in solving the problem of lipid accumulation in farmed fish.

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.

Gremlin in the Vitreous of Patients with Proliferative Diabetic Retinopathy and the Downregulation of Gremlin in Retinal Pigment Epithelial Cells

Diabetic retinopathy (DR) is one of the most common causes of blindness globally. Proliferative DR (PDR), an advanced stage of DR, is characterized by the formation of fibrotic membranes at the vitreoretinal interface. The proliferation, migration, and secretion of extracellular matrix molecules in retinal pigment epithelial (RPE) cells contribute to the formation of fibrotic membranes in PDR. Gremlin has been reported to be upregulated in response to elevated glucose levels in the retina of diabetic rat and bovine pericytes. However, the role of gremlin in PDR remains unclear. In the present study, the vitreous concentrations of gremlin were significantly higher in the PDR (67.79 ± 33.96) group than in the control (45.31 ± 12.31) group, and high glucose levels induced the expression of gremlin in RPE cells. The elevated expression of extracellular matrix molecules, such as fibronectin and collagen IV, was significantly reduced by gremlin siRNA in human RPE cells under high-glucose conditions. Thus, gremlin may play a vital role in the development of PDR.

Mitochondrial lipoylation integrates age-associated decline in brown fat thermogenesis

Thermogenesis in brown adipose tissue (BAT) declines with age; however, what regulates this process remains poorly understood. Here, we identify mitochondria lipoylation as a previously unappreciated molecular hallmark of aged BAT in mice. Using mitochondrial proteomics, we show that mitochondrial lipoylation is disproportionally reduced in aged BAT through a post-transcriptional decrease in the iron-sulfur (Fe-S) cluster formation pathway. A defect in the Fe-S cluster formation by the fat-specific deletion of Bola3 significantly reduces mitochondrial lipoylation and fuel oxidation in BAT, leading to glucose intolerance and obesity. In turn, enhanced mitochondrial lipoylation by α-lipoic acid supplementation effectively restores BAT function in old mice, thereby preventing age-associated obesity and glucose intolerance. The effect of α-lipoic acids requires mitochondrial lipoylation via the Bola3 pathway and does not depend on the anti-oxidant activity of α-lipoic acid. These results open up the possibility to alleviate the age-associated decline in energy expenditure by enhancing the mitochondrial lipoylation pathway.

Alpha lipoic acid protects against dexamethasone-induced metabolic abnormalities via APPL1 and PGC-1 α up regulation

BACKGROUND

Glucocorticoids (GCs) have various uses in the medicine in different specialties. However, GCs administration is usually accompanying with multiple side effects such as hyperglycemia and hyperlipidemia. Alpha lipoic acid (ALA) has been documented to posse anti-diabetic properties.

AIM OF THE STUDY

this study highlights the role of ALA in avoiding dexamethasone induced metabolic disturbance.

MATERIALS & METHODS

30 rats were randomly divided into 5 groups: Group (1): Control group; Groups 3, 4, and 5: rats received dexamethasone 1 mg/kg/day for 10 days; Groups 2, 4, and 5: Rats received ALA 100 mg/kg/day all the duration of the study, 2 weeks before dexamethasone, or concomitant with dexamethasone respectively. For each rat, we collected blood samples for measurement of glucose, lipid profiles, adiponectin, irisin, and Phosphoinositide 3-kinase (PI3K). We also isolated gastrocnemius muscles for measurement of insulin receptor substrate-1(IRS-1), peroxisome proliferator-activated receptor γ coactivator 1 α(PGC1-α), and adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1(APPL) gene expression.

RESULTS

Dexamethasone administration caused hyperglycemia, hyperlipemia, decrease the level of adiponectin, irisin, and PI3K besides decreasing the gene expression of IRS-1, PGC-1 α, and APPL1. ALA administration pre or concomitant to dexamethasone avoided these results.

CONCLUSION

ALA can prevent metabolic abnormalities induced by dexamethasone via PGC1α and APPL1 upregulation.

The effects of AICAR and rapamycin on mitochondrial function in immortalized mitochondrial DNA mutator murine embryonic fibroblasts

Mitochondrial DNA mutations accumulate with age and may play a role in stem cell aging as suggested by the premature aging phenotype of mitochondrial DNA polymerase gamma (POLG) exonuclease-deficient mice. Therefore, E1A immortalized murine embryonic fibroblasts (MEFs) from POLG exonuclease-deficient and wild-type (WT) mice were constructed. Surprisingly, when some E1A immortalized MEF lines were cultured in pyruvate-containing media they slowly became addicted to the pyruvate. The POLG exonuclease-deficient MEFs were more sensitive to several mitochondrial inhibitors and showed increased reactive oxygen species (ROS) production under standard conditions. When cultured in pyruvate-containing media, POLG exonuclease-deficient MEFs showed decreased oxygen consumption compared to controls. Increased AMP-activated protein kinase (AMPK) signaling and decreased mammalian target of rapamycin (mTOR) signaling delayed aging and influenced mitochondrial function. Therefore, the effects of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator, or rapamycin, an mTOR inhibitor, on measures of mitochondrial function were determined. Rapamycin treatment transiently increased respiration only in WT MEFs and, under most conditions, increased ATP levels. Short term AICAR treatment transiently increased ROS production and, under most conditions, decreased ATP levels. Chronic AICAR treatment decreased respiration and ROS production in WT MEFs. These results demonstrate the context-dependent effects of AICAR and rapamycin on mitochondrial function.

Summary: A novel mitochondrial DNA mutator murine embryonic fibroblast cell line was created and the effects of the anti-aging compounds rapamycin and AICAR on energy metabolism in these cells was determined.

Alpha-lipoic acid preserves skeletal muscle mass in type 2 diabetic OLETF rats

Background

Increased oxidative stress and impaired antioxidant defense are important mechanisms in the pathogenesis of diabetic myopathy. Alpha-lipoic acid (ALA) has been indicated as a weight-loss treatment in rodents and humans, but studies are limited. In the present study, we aimed to determine the influence of ALA, a potent biological antioxidant, on metabolic and growth processes in diabetic rat skeletal muscle.

Methods

Male 25-week-old type 2 diabetic rats (OLETF) were randomly divided into two groups, a control group (OLETF-C) and an ALA-treated group (OLETF-ALA) supplemented with 100 mg/kg ALA for 8 weeks. Age-matched, healthy, nondiabetic LETO (LETO-C) rats were used as controls.

Results

At 32 weeks of age, body weight was decreased by 6.8%, and the areas under the curve of IP-GTT, fasting glucose, and insulin were less in OLETF-ALA rats compared with OLETF-C rats. ALA significantly preserved muscle mass and enhanced muscle fiber cross-sectional area and fiber frequency percentage in the skeletal muscle of OLETF rats. Although the activation of myoD, myogenin, and myostatin in gastrocnemius muscle was significantly inhibited in OLETF-ALA rats relative to OLETF-C rats, there were no differences in the expression levels of muscle atrogin-1 and MuRF1 between the two groups. ALA treatment significantly increased the levels of phosphorylated 5'-AMPK, SIRT1, and PGC-1α, as well as the levels of phosphorylated AKT, mTOR, and p70S6 kinase in OLETF-ALA rats compared with OLETF-C rats. In contrast, the levels of phosphorylated p38 MAPK, IRS-1, and FOXO1 were decreased in OLETF-ALA rats compared with OLETF-C rats.

Conclusions

ALA treatment preserved mass in the gastrocnemius muscles of OLETF rats. ALA significantly upregulated the AMPK/SIRT1/PGC-1α and AKT/mTOR/p70S6K signaling pathways in OLETF rat skeletal muscle. Therefore, ALA may be a potential therapeutic intervention for skeletal muscle loss in animal models of insulin resistance.

Feeding mitochondria: Potential role of nutritional components to improve critical illness convalescence

Persistent physical impairment is frequently encountered after critical illness. Recent data point towards mitochondrial dysfunction as an important determinant of this phenomenon. This narrative review provides a comprehensive overview of the present knowledge of mitochondrial function during and after critical illness and the role and potential therapeutic applications of specific micronutrients to restore mitochondrial function. Increased lactate levels and decreased mitochondrial ATP-production are common findings during critical illness and considered to be associated with decreased activity of muscle mitochondrial complexes in the electron transfer system. Adequate nutrient levels are essential for mitochondrial function as several specific micronutrients play crucial roles in energy metabolism and ATP-production. We have addressed the role of B vitamins, ascorbic acid, α-tocopherol, selenium, zinc, coenzyme Q10, caffeine, melatonin, carnitine, nitrate, lipoic acid and taurine in mitochondrial function. B vitamins and lipoic acid are essential in the tricarboxylic acid cycle, while selenium, α-tocopherol, Coenzyme Q10, caffeine, and melatonin are suggested to boost the electron transfer system function. Carnitine is essential for fatty acid beta-oxidation. Selenium is involved in mitochondrial biogenesis. Notwithstanding the documented importance of several nutritional components for optimal mitochondrial function, at present, there are no studies providing directions for optimal requirements during or after critical illness although deficiencies of these specific micronutrients involved in mitochondrial metabolism are common. Considering the interplay between these specific micronutrients, future research should pay more attention to their combined supply to provide guidance for use in clinical practise. REVISION NUMBER: YCLNU-D-17-01092R2.

Biochemical and clinical relevance of alpha lipoic acid: antioxidant and anti-inflammatory activity, molecular pathways and therapeutic potential

BACKGROUND

The molecular nature of lipoic acid (LA) clarifies its capability of taking part to a variety of biochemical reactions where redox state is meaningful. The pivotal action of LA is the antioxidant activity due to its ability to scavenge and inactivate free radicals. Furthermore, LA has been shown to chelate toxic metals both directly and indirectly by its capability to enhance intracellular glutathione (GSH) levels. This last property is due to its ability to interact with GSH and recycle endogenous GSH. LA exhibits significant antioxidant activity protecting against oxidative damage in several diseases, including neurodegenerative disorders. Interestingly, LA is unique among natural antioxidants for its capability to satisfy a lot of requirements, making it a potentially highly effective therapeutic agent for many conditions related with oxidative damage. In particular, there are evidences showing that LA has therapeutic activity in lowering glucose levels in diabetic conditions. Similarly, LA supplementation has multiple beneficial effects on the regression of the mitochondrial function and on oxidative stress associated with several diseases and aging.

AIM

The aim of the present review is to describe the molecular mechanisms underlying the beneficial effects of LA under various experimental conditions and disease and how to exploit such effect for clinical purposes.

CONCLUSION

LA has pleiotropic effects in different pathways related with several diseases, its use as a potential therapeutic agent is very promising.

Alpha-lipoic acid supplement in obesity treatment: A systematic review and meta-analysis of clinical trials

BACKGROUND & AIMS

Previous studies have supported positive roles of antioxidant supplements on weight-loss. One antioxidant supplement is Alpha-lipoic acid. However, recommending ALA as an anti-obesity supplement remains controversial. Accordingly, the purpose of the present study was to perform a meta-analysis on the effects of ALA supplement on anthropometric indices among adult subjects.

METHODS

We searched five electronic databases till September 2016. Placebo-controlled clinical trials were included. Weighted Mean Difference (WMD) was pooled using a random-effects model.

RESULTS

Findings of 12 included trials indicated that ALA supplement reduced body weight (WMD: -0.69 kg; 95% CI: -1.27, -0.10; I² = 0%) and BMI (WMD: -0.38 kg/m²; 95% CI: -0.53, -0.24; I² = 0%) significantly compared to the placebo group. However, its effects on Waist Circumference (WC) was not significant (WMD: -0.30 cm; 95% CI: -1.18, 0.58; I² = 17.8%). Stratification by health status indicated that ALA decreased WC in unhealthy subjects (WMD: -2.00 cm; 95% CI: -4.19, 0.19; I² = 1.3%) more than healthy individuals (0.03 cm; 95% CI: -0.69, 0.75; I² = 0%).

CONCLUSIONS

The present study revealed that supplementation with ALA slightly but significantly decreased body weight and BMI. Safe dosage for ALA is up to 1200 mg/day. However, it seems that ALA cannot be cost-effective. Further studies are needed to clarify the effects of ALA on metabolic parameter in unhealthy obese individuals.

Alpha-lipoic acid (ALA) as a supplementation for weight loss: results from a meta-analysis of randomized controlled trials

OBJECTIVES

Obesity is associated with significant morbidity and mortality rates. Even modest weight loss may be associated with health benefits. Alpha-lipoic acid (ALA) is a naturally occurring antioxidant. Studies have suggested anti-obesity properties of ALA; however, results are inconsistent. The purpose of this study is to conduct a meta-analysis of the effect of ALA on weight and body mass index (BMI).

METHODS

A comprehensive, systematic literature search identified 10 articles on randomized, double-blind, placebo-controlled studies involving ALA. We conducted a meta-analysis of mean weight and BMI change differences between ALA and placebo treatment groups.

RESULTS

Alpha-lipoic acid treatment coincided with a statistically significant 1.27 kg (confidence interval = 0.25 to 2.29) greater mean weight loss compared with the placebo group. A significant overall mean BMI difference of -0.43 kg/ m² (confidence interval = -0.82 to -0.03) was found between the ALA and placebo groups. Meta-regression analysis showed no significance in ALA dose on BMI and weight changes. Study duration significantly affected BMI change, but not weight change.

CONCLUSIONS

Alpha-lipoic acid treatment showed small, yet significant short-term weight loss compared with placebo. Further research is needed to examine the effect of different doses and the long-term benefits of ALA on weight management.

Chronic treatment of (R)-α-lipoic acid reduces blood glucose and lipid levels in high-fat diet and low-dose streptozotocin-induced metabolic syndrome and type 2 diabetes in Sprague-Dawley rats

(R)‐ α ‐lipoic acid (ALA), an essential cofactor in mitochondrial respiration and a potential antioxidant, possesses a wide array of metabolic benefits including anti‐obesity, glucose lowering, insulin‐sensitizing, and lipid‐lowering effects. In this study, the curative effects of ALA (100 mg/kg) on a spectrum of conditions related to metabolic syndrome and type 2 diabetes (T2D) were investigated in a high‐fat diet (HFD)‐fed and low‐dose streptozotocin (STZ)‐induced rat model of metabolic syndrome and T2D. The marked rise in the levels of glucose, triglycerides, total‐cholesterol, LDL‐cholesterol, and VLDL‐cholesterol in the blood of HFD‐fed and low‐dose STZ‐injected rats were significantly reduced by ALA treatment. Furthermore, ALA treatment significantly increased the serum HDL‐cholesterol levels and tended to inhibit diabetes‐induced weight reduction. Mathematical computational analysis revealed that ALA also significantly improved insulin sensitivity and reduced the risk of atherosclerotic lesions and coronary atherogenesis. This study provides scientific evidence to substantiate the use of ALA to mitigate the glucose and lipid abnormality in metabolic syndrome and T2D.

Irbesartan ameliorates hyperlipidemia and liver steatosis in type 2 diabetic db/db mice via stimulating PPAR-γ, AMPK/Akt/mTOR signaling and autophagy

Irbesartan (Irb), a unique subset of angiotensin II receptor blockers (ARBs) with PPAR-γ activation function, has been reported to play a role in renal dysfunction, glucose metabolism, and abnormal lipid profile in diabetic animal models and humans. However, the underlying mechanisms that improve hyperlipidemia and liver steatosis are unclear. This study investigated the effects of Irb on lipid metabolism and hepatic steatosis using the spontaneous type 2 diabetic db/db mouse model. The results demonstrated body and liver weight, food consumption, lipid content in serum and liver tissue, and liver dysfunction as well as hepatic steatosis were increased in db/db mice compared with db/m mice, whereas the increases were reversed by Irb treatment. Moreover, Irb administration resulted in an increase in LC3BII as well as the LC3BII/I ratio through activating PPAR-γ and p-AMPK and inhibiting p-Akt and p-mTOR, thereby inducing autophagy in the db/db mouse liver. Therefore, our findings suggest that Irb can ameliorate hyperlipidemia and liver steatosis by upregulating the expression of PPAR-γ, activating the AMPK/Akt/mTOR signaling pathway and inducing liver autophagy.

PGC-1α, glucose metabolism and type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a chronic disease characterized by glucose metabolic disturbance. A number of transcription factors and coactivators are involved in this process. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is an important transcription coactivator regulating cellular energy metabolism. Accumulating evidence has indicated that PGC-1α is involved in the regulation of T2DM. Therefore, a better understanding of the roles of PGC-1α may shed light on more efficient therapeutic strategies. Here, we review the most recent progress on PGC-1α and discuss its regulatory network in major glucose metabolic tissues such as the liver, skeletal muscle, pancreas and kidney. The significant associations between PGC-1α polymorphisms and T2DM are also discussed in this review.

α-Lipoic Acids Promote the Protein Synthesis of C2C12 Myotubes by the TLR2/PI3K Signaling Pathway

Skeletal muscle protein turnover is regulated by endocrine hormones, nutrients, and inflammation. α-Lipoic acid (ALA) plays an important role in energy homeostasis. Therefore, the aim of this study was to investigate the effects of ALA on protein synthesis in skeletal muscles and reveal the underlying mechanism. ALA (25 μM) significantly increased the protein synthesis and phosphorylation of Akt, mTOR, and S6 in C2C12 myotubes with attenuated phosphorylation of AMPK, Ikkα/β, and eIF2α. Intraperitoneal injection of 50 mg/kg ALA also produced the same results in mouse gastrocnemius. Both the PI3K (LY294002) and mTOR (rapamycin) inhibitors abolished the effects of ALA on protein synthesis in the C2C12 myotubes. However, AICAR (AMPK agonist) failed to block the activation of mTOR and S6 by ALA. ALA increased TLR2 and MyD88 mRNA expression in the C2C12 myotubes. TLR2 knockdown by siRNA almost eliminated the effects of ALA on protein synthesis and the Akt/mTOR pathway in the C2C12 myotubes. Immunoprecipitation data showed that ALA enhanced the p85 subunit of PI3K binding to MyD88. These findings indicate that ALA induces protein synthesis and the PI3K/Akt signaling pathway by TLR2.

α-Lipoic acid up-regulates expression of peroxisome proliferator-activated receptor β in skeletal muscle: involvement of the JNK signaling pathway

We hypothesized that α-lipoic acid (α-LA) might interact with the transcriptional control of peroxisome proliferator-activated receptor (PPAR)β in skeletal muscle. Molecular mechanisms were investigated using differentiated C2C12 myotubes treated with α-LA and/or PPARβ agonist GW0742. In vivo studies with 3-mo-old C57Bl6 mice were realized: voluntary wheel running (VWR) training (7 wk), and a 6 wk diet containing (or not) α-LA (0.25% wt/wt). This last condition was combined with (or not) 1 bout of treadmill exercise (18 m/min for 1 h). Using a reporter assay, we demonstrate that α-LA is not an agonist of PPARβ but regulates PPARβ target gene expression through an active PPARβ pathway. GW0742-induced pyruvate dehydrogenase kinase 4 mRNA is potentiated by α-LA. In C2C12, α-LA lowers the activation of the JNK signaling pathway and increases PPARβ mRNA and protein levels (2-fold) to the same extent as with the JNK inhibitor SP600125. Similarly to VWR training effect, PPARβ expression increases (2-fold) in vastus lateralis of animals fed an α-LA-enriched diet. However, α-LA treatment does not further stimulate the adaptive up-regulation of PPARβ observed in response to 1 bout of exercise. We have identified a novel mechanism of regulation of PPARβ expression/action in skeletal muscle with potential physiologic application through the action of α-LA, involving the JNK pathway.

The Role of Organelle Stresses in Diabetes Mellitus and Obesity: Implication for Treatment

The type 2 diabetes pandemic in recent decades is a huge global health threat. This pandemic is primarily attributed to the surplus of nutrients and the increased prevalence of obesity worldwide. In contrast, calorie restriction and weight reduction can drastically prevent type 2 diabetes, indicating a central role of nutrient excess in the development of diabetes. Recently, the molecular links between excessive nutrients, organelle stress, and development of metabolic disease have been extensively studied. Specifically, excessive nutrients trigger endoplasmic reticulum stress and increase the production of mitochondrial reactive oxygen species, leading to activation of stress signaling pathway, inflammatory response, lipogenesis, and pancreatic beta-cell death. Autophagy is required for clearance of hepatic lipid clearance, alleviation of pancreatic beta-cell stress, and white adipocyte differentiation. ROS scavengers, chemical chaperones, and autophagy activators have demonstrated promising effects for the treatment of insulin resistance and diabetes in preclinical models. Further results from clinical trials are eagerly awaited.

Isomeric effects of anti-diabetic α-lipoic acid with γ-cyclodextrin

AIMS

Previous studies reported the anti-diabetic effects of α-lipoic acid (αLA) isomers: racemic-αLA, R-αLA, or S-αLA. Previously, we examined the anti-diabetic effects of αLA administered as a food additive, but were unable to demonstrate the differences among different isomers. In this study, αLAs were complexed with γ-cyclodextrin (γCD) for the stability.We then investigated the anti-diabetic effects of racemic-, R-, and S-αLA/γCDs in KKAy mice.

MAIN METHODS

Male type 2 diabetic KKAy mice were divided into 5 groups, and fed either a high-fat-diet (HFD),HFD supplemented with γCD, or HFD supplemented with racemic-αLA/γCD, R-αLA/γCD, or S-αLA/γCD for 4 weeks. At the end of the feeding period, HbA1c and adiponectin levels were measured, PPARγ2mRNA expression levels were assessed in adipose tissues using real-time PCR, and AMP-activated protein kinase (AMPK) phosphorylation levels were evaluated in the liver by Western blotting.

KEY FINDINGS

The anti-diabetic effects of αLA; the isomeric compounds racemic-, R-, and S-αLA/γCD were investigated using amale type 2 diabetic KKAy mousemodel. Significant differences were observed in HbA1c and plasma adiponectin levels between R-αLA/γCD-treated mice and control mice. PPARγ2 mRNA expression levels were slightly higher in racemic- and R-αLA/γCD-treated mice. Moreover, AMPK phosphorylation levels were elevated in racemic-αLA/γCD- and R-αLA/γCD-treated mice, but remained unchanged in S-αLA/γCD-treated mice.

SIGNIFICANCE

These results suggested that the stereoisomerism mediates a difference in the anti-diabetic effects of racemic-, R-, and S-αLA/γCDs. Furthermore, the anti-diabetic mechanism of αLA/γCD action may be attributed to the activation of AMPK in the liver.

Circulating irisin and glucose metabolism in overweight/obese women: effects of α-lipoic acid and eicosapentaenoic acid

Irisin is a myokine/adipokine with potential role in obesity and diabetes. The objectives of the present study were to analyse the relationship between irisin and glucose metabolism at baseline and during an oral glucose tolerance test (OGTT) and to determine the effects of eicosapentaenoic acid (EPA) and/or α-lipoic acid treatment on irisin production in cultured human adipocytes and in vivo in healthy overweight/obese women following a weight loss program. Seventy-three overweight/obese women followed a 30% energy-restricted diet supplemented without (control) or with EPA (1.3 g/day), α-lipoic acid (0.3 g/day) or both EPA + α-lipoic acid (1.3 + 0.3 g/day) during 10 weeks. An OGTT was performed at baseline. Moreover, human adipocytes were treated with EPA (100-200 μM) or α-lipoic acid (100-250 μM) during 24 h. At baseline plasma, irisin circulating levels were positively associated with glucose levels; however, serum irisin concentrations were not affected by the increment in blood glucose or insulin during the OGTT. Treatment with α-lipoic acid (250 μM) upregulated Fndc5 messenger RNA (mRNA) and irisin secretion in cultured adipocytes. In overweight/obese women, irisin circulating levels decreased significantly after weight loss in all groups, while no additional differences were induced by EPA or α-lipoic acid supplementation. Moreover, plasma irisin levels were positively associated with higher glucose concentrations at beginning and at endpoint of the study. The data from the OGTT suggest that glucose is not a direct contributing factor of irisin release. The higher irisin levels observed in overweight/obese conditions could be a protective response of organism to early glucose impairments.

Effects of α-lipoic acid and eicosapentaenoic acid in overweight and obese women during weight loss

OBJECTIVE

To evaluate the potential body weight-lowering effects of dietary supplementation with eicosapentaenoic acid (EPA) and α-lipoic acid separately or combined in healthy overweight/obese women following a hypocaloric diet.

METHODS

This is a short-term double-blind placebo-controlled study with parallel design that lasted 10 weeks. Of the randomized participants, 97 women received the allocated treatment [Control, EPA (1.3 g/d), α-lipoic acid (0.3 g/d), and EPA+α-lipoic acid (1.3 g/d+0.3 g/d)], and 77 volunteers completed the study. All groups followed an energy-restricted diet of 30% less than total energy expenditure. Body weight, anthropometric measurements, body composition, resting energy expenditure, blood pressure, serum glucose, and insulin and lipid profile, as well as leptin and ghrelin levels, were assessed at baseline and after nutritional intervention.

RESULTS

Body weight loss was significantly higher (P<0.05) in those groups supplemented with α-lipoic acid. EPA supplementation significantly attenuated (P<0.001) the decrease in leptin levels that occurs during weight loss. Body weight loss improved lipid and glucose metabolism parameters but without significant differences between groups.

CONCLUSIONS

The intervention suggests that α-lipoic acid supplementation alone or in combination with EPA may help to promote body weight loss in healthy overweight/obese women following energy-restricted diets.

The PI3K/Akt signaling pathway mediates the high glucose-induced expression of extracellular matrix molecules in human retinal pigment epithelial cells

Prolonged hyperglycemia is an important risk factor of the pathogenesis of diabetic retinopathy (DR). Extracellular matrix molecules, such as fibronectin, collagen IV, and laminin, are associated with fibrotic membranes. In this study, we investigated the expression of fibronectin, collagen IV, and laminin in RPE cells under high glucose conditions. Furthermore, we also detected the phosphorylation of protein kinase B (Akt) under high glucose conditions in RPE cells. Our results showed that high glucose upregulated fibronectin, collagen IV, and laminin expression, and activated Akt in RPE cells. We also found that pretreatment with LY294002 (an inhibitor of phosphatidylinositol 3-kinase) abolished high glucose-induced expression of fibronectin, collagen IV, and laminin in RPE cells. Thus, high glucose induced the expression of fibronectin, collagen IV, and laminin through PI3K/Akt signaling pathway in RPE cells, and the PI3K/Akt signaling pathway may contribute to the formation of fibrotic membrane during the development of DR.

Alpha-lipoic acid supplementation reduces mTORC1 signaling in skeletal muscle from high fat fed, obese Zucker rats

The mammalian target of rapamycin (mTOR) signaling pathway is hyperactive in liver, adipose and skeletal muscle tissues of obese rodents. Alpha-lipoic acid (αLA) has been well accepted as a weight-loss treatment, though there are limited studies on its effect on mTOR signaling in high-fat fed, obese rodents. Therefore, the goal of this study was to determine mTOR signaling and oxidative protein alterations in skeletal muscle of high-fat fed, obese rats after αLA supplementation. Phosphorylation of the mTOR substrate, eukaryotic initiation factor (eIF) 4E-binding protein 1 (4E-BP1) and eIF4B were significantly reduced (p < 0.05) in muscle from αLA supplemented rats. Activation of AMP-activated protein kinase (AMPK), an mTOR inhibitory kinase, was higher (p < 0.05) in the αLA group. Protein expression of markers of oxidative metabolism, acetyl CoA carboxylase (ACC), cytochrome c oxidase IV (COX IV), peroxisome proliferator-activated receptor (PPAR), and PPAR gamma coactivator 1-alpha (PGC-1α) were significantly higher (p < 0.05) after αLA supplementation compared to non-supplemented group. Our findings show that αLA supplementation limits the negative ramifications of consuming a high fat diet on skeletal muscle markers of oxidative metabolism and mTORC1 signaling.

Unraveling biochemical pathways affected by mitochondrial dysfunctions using metabolomic approaches

Mitochondrial dysfunction(s) (MDs) can be defined as alterations in the mitochondria, including mitochondrial uncoupling, mitochondrial depolarization, inhibition of the mitochondrial respiratory chain, mitochondrial network fragmentation, mitochondrial or nuclear DNA mutations and the mitochondrial accumulation of protein aggregates. All these MDs are known to alter the capacity of ATP production and are observed in several pathological states/diseases, including cancer, obesity, muscle and neurological disorders. The induction of MDs can also alter the secretion of several metabolites, reactive oxygen species production and modify several cell-signalling pathways to resolve the mitochondrial dysfunction or ultimately trigger cell death. Many metabolites, such as fatty acids and derived compounds, could be secreted into the blood stream by cells suffering from mitochondrial alterations. In this review, we summarize how a mitochondrial uncoupling can modify metabolites, the signalling pathways and transcription factors involved in this process. We describe how to identify the causes or consequences of mitochondrial dysfunction using metabolomics (liquid and gas chromatography associated with mass spectrometry analysis, NMR spectroscopy) in the obesity and insulin resistance thematic.

Antidiabetic effect of the α-lipoic acid γ-cyclodextrin complex

In recent years, the number of patients suffering from diabetes mellitus has been increasing worldwide. In particular, type 2 diabetes mellitus, a lifestyle-related disease, is recognized as a serious disease with various complications. Many types of pharmaceutics or specific health foods have been used for the management of diabetes mellitus. At the same time, the relationship between diabetes mellitus and α-lipoic acid has been recognized for many years. In this study, we found that the α-lipoic acid γ-cyclodextrin complex exhibited an HbA_1c lowering effect for treating type 2 diabetes mellitus in animal models. Moreover, in this study, we investigated the activation of phosphorylation of AMP-activated protein kinase, which plays a role in cellular energy homeostasis, in the liver of KKA^y mice by using α-lipoic acid and the α-lipoic acid γ-cyclodextrin complex. Our results show that the α-lipoic acid γ-cyclodextrin complex strongly induced the phosphorylation of AMP-activated protein kinase. Thus, we concluded that intake of the α-lipoic acid γ-cyclodextrin complex exerted an antidiabetic effect by suppressing the elevation of postprandial hyperglycemia as well as doing exercise.

Alpha-lipoic acid as a pleiotropic compound with potential therapeutic use in diabetes and other chronic diseases

Alpha-lipoic acid is a naturally occurring substance, essential for the function of different enzymes that take part in mitochondria's oxidative metabolism. It is believed that alpha-lipoic acid or its reduced form, dihydrolipoic acid have many biochemical functions acting as biological antioxidants, as metal chelators, reducers of the oxidized forms of other antioxidant agents such as vitamin C and E, and modulator of the signaling transduction of several pathways. These above-mentioned actions have been shown in experimental studies emphasizing the use of alpha-lipoic acid as a potential therapeutic agent for many chronic diseases with great epidemiological as well economic and social impact such as brain diseases and cognitive dysfunctions like Alzheimer disease, obesity, nonalcoholic fatty liver disease, burning mouth syndrome, cardiovascular disease, hypertension, some types of cancer, glaucoma and osteoporosis. Many conflicting data have been found concerning the clinical use of alpha-lipoic acid in the treatment of diabetes and of diabetes-related chronic complications such as retinopathy, nephropathy, neuropathy, wound healing and diabetic cardiovascular autonomic neuropathy. The most frequent clinical condition in which alpha-lipoic acid has been studied was in the management of diabetic peripheral neuropathy in patients with type 1 as well type 2 diabetes. Considering that oxidative stress, a imbalance between pro and antioxidants with excessive production of reactive oxygen species, is a factor in the development of many diseases and that alpha-lipoic acid, a natural thiol antioxidant, has been shown to have beneficial effects on oxidative stress parameters in various tissues we wrote this article in order to make an up-to-date review of current thinking regarding alpha-lipoic acid and its use as an antioxidant drug therapy for a myriad of diseases that could have potential benefits from its use.