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

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

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

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.

Alpha-lipoic acid, apocynin or probiotics influence glutathione status and selected inflammatory parameters in C57/BL6 mice when combined with a low-fat diet

BACKGROUND

The aim of the study was to determine the potential of a low-fat diet (LFD) to protect against oxidative and inflammatory damage in the course of asthma and obesity when combined with antioxidants (alpha-lipoic acid-ALA, apocynin-APO) or a probiotic (P) (Lactobacillus casei).

METHODS

The experiments were carried out on ten groups of male C57/BL6 mice that were fed standard fat (SFD), low-fat (LFD), or high-fat (HFD) diets. Ovalbumin (OVA, administered subcutaneously and by inhalation) was used to sensitize the animals. IL-1α, IL-10, eotaxin-1, leptin, and TNF-α concentrations were examined in blood, while total glutathione (GSHt), reduced glutathione (GSH), oxidized glutathione (GSSG) and -SH groups were measured in lung homogenates.

RESULTS

LFD in combination with the analyzed compounds (APO, P, ALA) significantly decreased the concentration of IL-1α compared to the OVA + HFD group (p < 0.01; p = 0.025; p = 0.002, respectively). Similarly, the treated mice demonstrated lower eotaxin-1 concentrations compared to the HFD group (p < 0.001). Moreover, supplementation of LFD with probiotics significantly increased the concentration of IL-10 vs. controls (p < 0.001) and vs. untreated OVA-sensitized and challenged/obese mice (p < 0.001). Animals administered APO/ALA with LFD displayed a significant decrease in TNF-α concentration compared to OVA + HFD mice (p = 0.013; p = 0.002 respectively). Those treated with ALA displayed significantly improved GSH levels (p = 0.035) compared to OVA + HFD mice.

CONCLUSIONS

Supplementation of the tested compounds with LFD appears to have a positive influence on the glutathione redox status of pulmonary tissues and selected inflammatory parameters in mouse blood.

Neuroprotective Effect of α-Lipoic Acid against Aβ25-35-Induced Damage in BV2 Cells

The prevalence of Alzheimer's disease (AD) is significantly increasing due to the aging world population, and the currently available drug treatments cannot cure or even slow its progression. α-lipoic acid (LA) is a biological factor widely found in spinach and meat and can dissolve in both lipid and aqueous phases. In medicine, LA has been shown to reduce the symptoms of diabetic polyneuropathy, acute kidney injury, cancers, and some metabolism-related diseases. This study to proves that α-lipoic acid (LA) can stabilize the cognitive function of patients with Alzheimer's disease (AD). BV2 cells were divided into control, LA, Aβ_25-35, and LA + Aβ_25-35 groups. Cell growth; IL-6, IL-1β, TNF-α, IFN-γ, SOD, GPx, CAT, ROS, NO, and iNOS secretion; Wnt-related proteins; cell apoptosis; and cell activation were examined. Here, we found that LA could effectively repress apoptosis and changes in the morphology of microglia BV2 cells activated by Aβ_25-35, accompanied by the inhibition of the inflammatory response induced by Aβ_25-35. The Wnt/β-catenin pathway is also involved in preventing Aβ_25-35-induced cytotoxicity in microglia by LA. We found an inhibitory effect of LA on microglia toxicity induced by Aβ_25-35, suggesting that a combination of anti-inflammatory and antioxidant substances may offer a promising approach to the treatment of AD.

Pharmacological evaluation of Thuja occidentalis for the attenuation of neuropathy via AGEs and TNF-α inhibition in diabetic neuropathic rats

When diabetes neuropathy occurs, the oxidative stress caused by chronic hyperglycemia may result in chronic neuronal damage. To mitigate the effects of hyperglycemia-induced neuronal damage, it may be beneficial to address oxidative stress and inflammation in the body. The current study evaluated the neuroprotective efficacy of Thuja occidentalis in streptozotocin (STZ)-nicotinamide (NAD)-induced diabetic neuropathy in male Wistar rats. A single dose of STZ (65 mg/kg, i.p.) was used to induce diabetic neuropathy in Wistar rats. Serum insulin, glucose, hyperalgesia, oxidative stress, inflammatory markers, and histopathology of the sciatic nerve were evaluated for neuropathy. Wistar rats were treated with varying doses of hydroalcoholic extracts of Thuja occidentalis (HAETO) and gabapentin for 30 days. Thuja occidentalis considerably corrected the levels of inflammatory markers and oxidative stress caused by hyperglycemia; also, it led to the restoration of neuronal functions, indicating that it is effective in treating diabetic neuropathy. Furthermore, the molecular docking of thujone at the active pockets of various inflammatory mediators (IL-1β, IL-6, TGF-β1, and TNF-α) has shown good interactions with critical amino acid residues. These findings indicate that the hydroalcoholic extract of Thuja occidentalis effectively inhibits the development of diabetic neuropathy. The hypoglycemic, antioxidant, anti-hyperalgesia, and anti-inflammatory properties of Thuja occidentalis are thought to be responsible for the neuroprotective benefit.

Topical application of Aloe gel and/or olive oil combination promotes the wound healing properties of streptozotocin-induced diabetic rats

Diabetic wounds are characterized by a delayed closure rate due to the excess inflammation and the inhibition of angiogenesis. Natural products derived from Aloe vera have shown great promise due to their healing magnificent properties. Olive oil is another natural product with anti-microbial and anti-inflammatory properties that may contribute to the healing process. In the present investigation, we tried to evaluate the efficacy of topical application of Aloe gel and/or olive oil in the enhancement of diabetic wounds using histological and immunohistochemical analysis. Excisional wounds were created on the back skin of streptozotocin-induced diabetic rats. Topical treatments of Aloe gel and/or olive oil were applied separately and in a combination (AVO) daily for experimental groups. Macroscopic and microscopic observations of the excision wounds were monitored at time intervals (3, 6, 9, 14 days) post-wounding. Macroscopic observations of the AVO group exhibited almost complete healing at day 14, while other groups were still in progress. Similarly, immunohistochemical analysis of the AVO group showed a mild expression pattern of NF-κB.. While, the cell proliferation (Ki-67), and angiogenesis (CD34) markers were upregulated. Conclusively, the obtained results showed that the AVO combination effectively improved the healing process in diabetic excisional wounds with significant differences in the healing kinetics compared to wounds that received Aloe gel or olive oil separately.

Supplementation of freezing media with alpha lipoic acid preserves the structural and functional characteristics of sperm against cryodamage in infertile men with asthenoteratozoospermia

The aim of this study was to examine the effects of alpha lipoic acid (ALA) supplementation during semen cryopreservation on the sperm quality, chromatin integrity, oxidative stress, and expression level of BAX, BCL2, HSP70 and iNOS genes in semen samples obtained from infertile men with asthenoteratozoospermia.

METHODS

Twenty freshly ejaculated semen samples were cryopreserved with sperm freezing medium supplemented with 0.00, 0.02, 0.05, 0.1, 0.5, and 1 mmol/mL of ALA. The samples were analyzed according to the WHO guidelines before and after freezing. Sperm ROS production level, DNA fragmentation and cryo-capacitation were assessed using flow cytometry, TUNEL assay and chlortetracycline (CTC) test, respectively. Expression level of stress protein (HSP70), pro-apoptotic Bax, anti-apoptotic Bcl-2, and iNOS genes was assessed by real-time PCR assay.

RESULTS

The effective concentrations of ALA (0.02 and 0.5 mM) significantly improved the motility, viability and morphology of the frozen-thawed sperms compared to the control group treated with 0.00 mM of ALA. During cryopreservation, treatment of semen with 0.02 mM of ALA, as the optimal concentration, significantly decreased DNA fragmentation and oxidative stress level (P < 0.05), protected the acrosome integrity, and led to insignificant reduction in BAX gene expression level and significant increase in expression level of BCL2, HSP70, and iNOS genes compared with control group.

CONCLUSION

Our findings revealed that the adding ALA to semen samples obtained from infertile men with asthenoteratozoospermia plays a significant protective role against cryodamage by preserving the sperm functional parameters.

Alpha-lipoic acid effect on leptin and adiponectin concentrations: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

New evidence suggests that dysregulation of adipocytokines caused by excess adiposity plays an important role in the pathogenesis of various obesity comorbidities. Our aim in this meta-analysis was to determine the effect of alpha-lipoic acid (ALA) supplementation on serum levels of leptin and adiponectin.

METHODS

We searched Scopus, PubMed, Google Scholar, and ISI Web of Science from inception up to July 2019. Mean difference for leptin and adiponectin were calculated by subtracting the change from baseline in each study group. Summary estimates for the overall effect of ALA on serum leptin and adiponectin concentrations were calculated using random effects model. Results were presented as weighted mean difference (WMD) and their 95% confidence intervals (CI). Between-study heterogeneity was examined using the I² statistics.

RESULT

Eight studies were included in systematic review and seven studies in meta-analysis. The overall effect suggested a significant decrement in serum leptin concentrations (WMD = - 3.63; 95% CI, - 5.63, - 1.64 μg/ml; I² = 80.7%) and a significant increase in serum levels of adiponectin (WMD = 1.98 μg/ml; 95% CI, 0.92, 3.04; I² = 95.7%). Subgroup analyses based on age showed a significant reduction in leptin levels only in younger adults, and subgroup analysis based on duration indicated in studies with a duration of more than 8 weeks adiponectin levels increased significantly and leptin levels decreased significantly.

CONCLUSION

Our results revealed ALA decreased leptin and increased adiponectin especially in studies lasted more than 8 weeks. We still need more studies with different ALA dose, intervention duration, and separately on male and female.

Morphofunctional condition of the pancreatic insular apparatus in old rats with alloxan-induced diabetes and its correction with lipoic acid

The concentration of glucose and glycosylated hemoglobin in the blood of animals increases as a result of physiological aging. This is due to damage to the pancreatic insular apparatus and a decrease in the number and functioning of active β-cells. The development of alloxan-induced diabetes in old rats is characterized by a decrease in the number of islets of Langerhans, an enlargement of the preserved islets, and a sharp decrease in the number of active endocrine cells. The injection of lipoic acid partially corrected the morphofunctional condition of the islets of Langerhans and the biochemical values of the animals’ peripheral blood.

Perspectives on the use of lipoic acid in the support of disease treatment*

Lipoic acid (LA) is a natural compound present in food and used as a dietary supplement. LA is endogenously synthetized in small amounts from octanoid acid in the mitochondria. This compound occurs naturally in vegetables such as spinach, broccoli and in animal tissues, in the kidneys, heart and liver. It has been shown that LA is a cofactor in the multienzyme complexes that are responsible for oxidative decarboxylation of α- ketoacids. LA and its reduced form, dihydrolipoic acid (DHLA), have many biological functions leading to a wide variety of actions such as anti-inflammation and antioxidant protection, scavenging of reactive oxygen species, regenerating other antioxidant agents, such as vitamins C and E, and cytosolic glutathione, chelating the transitional metal ions (e.g. iron and copper), and modulating the signal transduction of nuclear factor. Many authors regard LA as a potentially useful agent in the treatment and/or prevention of many diseases such as diabetes mellitus, overweight, obesity, hypertension, heart diseases, inflammation. This review concentrates on the role of LA in the treatment of diabetes mellitus, obesity, inflammation and blood pressure regulation. LA can be considered as a potentially useful drug in treatment of many diseases, particularly those related to excessive production of free radicals.

Metabolic effects of α-lipoic acid supplementation in pre-diabetics: a randomized, placebo-controlled pilot study

Supplementation of health promoting nutraceuticals may be an effective adjunct strategy with other lifestyle and drug approaches to impede disease progression in prediabetic subjects. α-Lipoic acid, a naturally occurring short-chain fatty acid, has been extensively evaluated for its antioxidant and glycemic control properties but has rarely been investigated as a lipid-lowering strategy. We conducted a pilot study to examine the effects of α-lipoic acid supplementation on glycemic control and lipid profile in pre-diabetic, overweight/obese adults. The study was designed as a free-living, randomized, two-phase, placebo-controlled cross-over study with 12 pre-diabetic, dyslipidemic subjects. Eligible subjects completed two thirty-day phases (in random order) consisting of a placebo (600 mg cellulose per day) and α-lipoic acid treatment (600 mg day^-1). Although no change (p < 0.05) in serum glucose was observed, α-lipoic acid-supplemented subjects demonstrated reduced fasting serum insulin (p = 0.04) and HOMA-IR (p = 0.07) compared with the placebo group. However, no change (p > 0.05) in serum lipids (including total cholesterol, LDL-C, HDL-C, triglycerides, LDL-C/HDL-C, and TC/HDL-C) were observed. Study results suggest that α-lipoic acid supplementation may be a useful strategy to improve insulin sensitivity in pre-diabetic subjects but is not effective in modulating serum lipids.

Oral α-lipoic acid supplementation in patients with non-alcoholic fatty liver disease: effects on adipokines and liver histology features

Considering the importance of adipokines in the pathophysiology of non-alcoholic fatty liver disease (NAFLD), and due to the possible beneficial effects of α-lipoic acid (α-LA) on these adipose-derived hormones, this study aimed to investigate the effect of α-LA supplementation on adipokines and liver steatosis in obese patients with NAFLD. In a double-blind, placebo-controlled randomized clinical trial with two parallel groups, fifty patients with NAFLD were randomized to receive daily supplementation with either two capsules of α-LA (each capsule containing 600 mg α-LA) or two placebo capsules, daily for 12 weeks. At the baseline, all participants received consultation on how to implement a healthy diet into their daily lives. Anthropometric measures, dietary intakes, liver enzymes and adipokines were assessed at the baseline and after 12 weeks of intervention. A significant reduction was observed in the serum levels of insulin (P = 0.024) and leptin (P = 0.019) in the α-LA group compared to the placebo group, but changes in anthropometric and body composition measures, serum glucose (FSG), resistin, irisin and liver enzymes did not differ between the groups. α-LA supplementation resulted in a statistically significant elevation in the quantitative insulin sensitivity check index (QUICKI) (P = 0.033), serum levels of adiponectin (P = 0.008) and adiponectin-to-leptin ratio (P = 0.007) compared to the placebo. The liver steatosis intensity improved significantly. Nonetheless, no significant differences were observed between the study groups in the liver steatosis intensity, at the end of the study. According to the results, α-LA supplementation for 12 weeks improved insulin resistance, serum levels of insulin, adiponectin and leptin without changing anthropometric measures, serum liver enzymes, resistin and irisin.

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.

α-lipoic acid attenuates spatial learning and memory impairment induced by hepatectomy

The aim of the present study was to compare the effects of α-lipoic acid (ALA) on postoperative cognitive dysfunction (POCD) between wild type (WT) and leptin receptor-deficient (db/db) mice and to elucidate the underlying mechanism of treatment with ALA. The present study compared the effects of ALA on spatial learning and memory of WT and db/db mice using a Morris water maze following hepatectomy. The expression levels of proteins, including cyclin-dependent kinase 5 (Cdk5), tau, phosphorylated tau and amyloid β (Aβ) were measured in the hippocampus. Surgery impaired postoperative cognitive function in both WT and db/db mice. Furthermore, the expression levels of Cdk5 and Aβ, and the phosphorylation of tau in the hippocampus increased after the surgery in both WT and db/db mice. The ultrastructure of hippocampal neurons and synapses was analyzed by transmission electron microscopy and the results revealed that surgery damaged the structure of neurons and synapses in both WT and db/db mice. Treatment with ALA protected the postoperative cognitive function and the structure of hippocampal neurons and synapses, and prevented the increase in protein expression levels of Cdk5 and Aβ, and the phosphorylation of tau in the hippocampus of WT but not db/db mice. The results of the present study suggest that ALA may be used for the treatment of POCD. The molecular mechanisms underlying the activity of ALA require further investigation.

THE EFFECT OF SHORT TERM ALPHA LIPOIC ACID ADMINISTRATION ON ADIPONECTIN AND BODY WEIGHT IN TYPE 2 DIABETES MELLITUS PATIENTS

Background

Alpha lipoic acid (ALA) acts as essential co-factor for mitochondrion respiratory enzymes. It has an increasing importance in diabetic neuropathy treatment. Its positive effects on weight gain and metabolic parameters have also been discussed. In this study, we aimed to search for the effect of ALA on weight, appetite, adiponectin and metabolic parameters in type 2 diabetes mellitus patients.

Methods

This study is designed as a randomised, double-blind, placebo controlled, prospective study. 23 type 2 diabetes mellitus patients with peripheral neuropathy (6 normal weight, 17 obese) and 21 normal weight control group were included in the study. Patients were given 600mg/day oral ALA for 6 weeks, added to their routine therapy. Body mass index (BMI), adiponectin, fasting plasma glucose, HbA1C, lipid parameters and CRP levels were tested before and after ALA treatment. Results were evaluated using SPSS 15.0 for Windows.

Results

Adiponectin levels were statistically significantly lower and CRP levels were higher in diabetes group when compared to control group. Although ALA treatment caused a slight weight loss, it was not statistically significant. Appetite scores were decreased in the diabetes group but it did not cause statistically significant weight loss. There was no significant change in metabolic parameters or adiponectin after the treatment.

Conclusions

600mg/dL ALA treatment for 6 weeks did not favor for metabolic parameters in type 2 diabetes patients. This result might be due to the dose or the duration of the treatment, genetic predisposition or dietery habits. Trial of higher doses for long terms might be needed for recovery.

Phospholipid complex enriched micelles: A novel drug delivery approach for promoting the antidiabetic effect of repaglinide

To enhance the oral antidiabetic effect of repaglinide (RG), a newly emerging approach, based on the combination of phospholipid complexation and micelle techniques, was employed. Repaglinide-phospholipid complex (RG-PLC) was prepared by the solvent-evaporation method then characterized using Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XPRD). The results revealed obvious disappearance of the characteristic peaks of the prepared RG-PLCs confirming the formation of drug-phospholipid complex. RG-PLC enriched micelles (RG-PLC-Ms) were prepared by the solvent-evaporation technique employing poloxamer 188 as surfactant. The prepared RG-PLC-Ms showed high drug encapsulation efficiencies (93.81-99.38%), with nanometric particle diameters (500.61-665.32nm) of monodisperse distribution and high stability (Zeta potential < -29.8mV). The in vitro release of RG from RG-PLC-Ms was pH-dependant according to the release media. A higher release pattern was reported in pH=1.2 compared to a more retarded release in pH=6.8 owing to two different kinetics of drug release. Oral antidiabetic effect of two optimized RG-PLC-M formulations was evaluated in an alloxan-induced diabetic rat model for 7-day treatment protocol. The two investigated formulations depicted normal blood glucose, serum malondialdehyde and insulin levels as well as an improved lipid profile, at the end of daily oral treatment, in contrast to RG marketed tablets implying enhanced antidiabetic effect of the drug. Hence, phospholipid-complex enriched micelles approach holds a promising potential for promoting the antidiabetic effect of RG.

Evaluation of Trigonella foenum-graecum extract in combination with swimming exercise compared to glibenclamide consumption on type 2 Diabetic rodents

Background/objective

The purpose of the present study was to evaluate the effect of fenugreek seed extract in combination with swimming exercise compared to glibenclamide consumption on type 2 diabetic rats.

Design

The acute toxicity test was carried out to choose the safe doses and identify the toxicity effects of the fenugreek seed extract. To investigate the hypoglycemic effect of the extract and its effect in combination with swimming training, 80 Wistar Kyoto male streptozotocin-induced diabetic rats were divided randomly into eight groups: diabetic control (C); fenugreek seed extract 0.8 g/kg (F1); fenugreek extract 1.6 g/kg (F2); swimming training (S); swimming training plus fenugreek extract 0.8 g/kg (SF1); swimming training plus fenugreek extract 1.6 g/kg (SF2); glibenclamide (G) and swimming training plus glibenclamide (SG). The rats were orally administrated with the treatments once a day with the respective treatment, and the training groups were subjected to swimming training every day for 60 min. Fasting blood samples were collected to measure fasting blood glucose, lipid profile, adiponectin, leptin, and insulin concentrations.

Results

The results obtained from acute toxicity study showed no toxicity effect of fenugreek seed extract on the tested dose. Biochemical analysis showed significant improvements in all of the groups compared to the control group (p<0.05). Plasma insulin concentration and insulin resistance (HOMA-IR) was significantly reduced in treated groups compared with the diabetic control group. Plasma leptin were significantly decreased in treated groups compared with the control group; while adiponectin had markedly increased (p<0.05).

Conclusion

The findings suggest that fenugreek seed consuming, alongside swimming exercise, has a strong therapeutic effect on the improvement of diabetic parameters.

Alpha-lipoic acid reduces LDL-particle number and PCSK9 concentrations in high-fat fed obese Zucker rats

We characterized the hypolipidemic effects of alpha-lipoic acid (LA, R-form) and examined the associated molecular mechanisms in a high fat fed Zucker rat model. Rats (n = 8) were assigned to a high fat (HF) diet or the HF diet with 0.25% LA (HF-LA) for 30 days and pair fed to remove confounding effects associated with the anorectic properties of LA. Compared with the HF controls, the HF-LA group was protected against diet-induced obesity (102.5±3.1 vs. 121.5±3.6,% change BW) and hypercholesterolemia with a reduction in total-C (−21%), non-HDL-C (−25%), LDL-C (−16%), and total LDL particle number (−46%) and an increase in total HDL particles (∼22%). This cholesterol-lowering response was associated with a reduction in plasma PCSK9 concentration (−70%) and an increase in hepatic LDLr receptor protein abundance (2 fold of HF). Compared with the HF-fed animals, livers of LA-supplemented animals were protected against TG accumulation (−46%), likely through multiple mechanisms including: a suppressed lipogenic response (down-regulation of hepatic acetyl-CoA carboxylase and fatty acid synthase expression); enhanced hepatic fat oxidation (increased carnitine palmitoyltransferase Iα expression); and enhanced VLDL export (increased hepatic diacylglycerol acyltransferase and microsomal triglyceride transfer protein expression and elevated plasma VLDL particle number). Study results also support an enhanced fatty acid uptake (2.8 fold increase in total lipase activity) and oxidation (increased CPT1β protein abundance) in muscle tissue in LA-supplemented animals compared with the HF group. In summary, in the absence of a change in caloric intake, LA was effective in protecting against hypercholesterolemia and hepatic fat accumulation under conditions of strong genetic and dietary predisposition toward obesity and dyslipidemia.

The effect of dietary α-lipoic acid, betaine,l-carnitine, and swimming on the obesity of mice induced by a high-fat diet

We evaluate the effect of supplementation, at 300 mg kg⁻¹body weight (BW), with the antioxidants α-lipoic acid (AL), betaine (BT),l-carnitine (LC), and the combination of these and exercise on obesity induced by a 9 week high-fat diet (HFD) in mice.

The Effect of Lipoic Acid Therapy on Cognitive Functioning in Patients with Alzheimer's Disease

Diabetes mellitus (DM) is an important risk factor for Alzheimer's disease (AD). Most diabetic patients have insulin resistance (IR) that is associated with compensatory hyperinsulinemia, one of the mechanisms suggested for increased AD risk in patients with DM. Alpha-lipoic acid (ALA) is a disulfide molecule with antioxidant properties that has positive effects on glucose metabolism and IR. This study evaluated the effect of ALA treatment (600 mg/day) on cognitive performances in AD patients with and without DM. One hundred and twenty-six patients with AD were divided into two groups, according to DM presence (group A) or absence (group B). Cognitive functions were assessed by MMSE, Alzheimer's Disease Assessment Scale-cognitive (ADAS-Cog), Clinician's Interview-Based Impression of Severity (CIBIC), Clinical Dementia Rating (CDR), and Alzheimer's Disease Functional and Change Scale (ADFACS). IR was assessed by HOMA index. At the end of the study, MMSE scores showed a significant improvement in 43% patients of group A (26 subjects) and 23% of group B (15 subjects), compared to baseline (P = .001). Also ADAS-Cog, CIBIC, and ADFACS scores showed a significant improvement in group A versus group B. IR was higher in group A. Our study suggests that ALA therapy could be effective in slowing cognitive decline in patients with AD and IR.

α-Lipoic acid reduced weight gain and improved the lipid profile in rats fed with high fat diet

The purpose of this study was to investigate the effects of α-lipoic acid on body weight and lipid profiles in Sprague-Dawley rats fed a high fat diet (HFD). After 4 weeks of feeding, rats on the HFD were divided into three groups by randomized block design; the first group received the high-fat-diet (n = 10), and the second group received the HFD administered with 0.25% α-lipoic acid (0.25LA), and the third group received the high-fat diet with 0.5% α-lipoic acid (0.5LA). The high fat diet with α-lipoic acid supplemented groups had significantly inhibited body weight gain, compared to that in the HFD group (P < 0.05). Organ weights of rats were also significantly reduced in liver, kidney, spleen, and visible fat tissues in rats supplemented with α-lipoic acid (P < 0.05). Significant differences in plasma lipid profiles, such as total lipids, total cholesterol, triglycerides, low-density lipoprotein, and high-density lipoprotein, were observed between the HFD and 0.5LA groups. The atherogenic index and the plasma high density lipoprotein-cholesterol/total cholesterol ratio improved significantly with α-lipoic acid supplementation in a dose-dependent manner (P < 0.05). Total hepatic cholesterol and total lipid concentration decreased significantly in high fat fed rats supplemented with α-lipoic acid in a dose-dependent manner (P < 0.05), whereas liver triglyceride content was not affected. In conclusion, α-lipoic acid supplementation had a positive effect on weight gain and plasma and liver lipid profiles in rats.