Resveratrol ameliorates metabolic disorders and muscle wasting in streptozotocin-induced diabetic rats

Metabolic profiling reveals the nutraceutical effect of Gongolaria abies-marina and Rosmarinus officinalis extracts in a type 1 diabetes animal model

Nutraceuticals have gained increasing interest, prompting the need to investigate plant extracts for their beneficial properties and potential side effects. This study aimed to assess the nutraceutical effects of environmentally clean extracts from Rosmarinus officinalis and Gongolaria abies-marina (formerly Cystoseira abies-marina (Phaeophyceae)) on the metabolic profile of streptozotocin-induced diabetic rats. We conducted untargeted LC-QTOF-MS metabolic profiling on six groups of rats: three diabetic groups receiving either a placebo, R. officinalis, or G. abies-marina extracts, and three corresponding control groups. The metabolic analysis revealed significant alterations in the levels of various glycerophospholipids, sterol lipids, and fatty acyls. Both extracts influenced the metabolic profile, partially mitigating diabetes-induced changes. Notably, G. abies-marina extract had a more pronounced impact on the animals' metabolic profiles compared to R. officinalis. In conclusion, our findings suggest that environmentally clean extracts from R. officinalis and G. abies-marina possess nutraceutical potential, as they were able to modulate the metabolic profile in streptozotocin-induced diabetic rats. G. abies-marina extract exhibited a more substantial effect on metabolic alterations induced by diabetes compared to R. officinalis. These results warrant further exploration of these plant extracts for their potential in managing diabetes-related metabolic disturbances.

The Effects of Antioxidants and Pulsed Magnetic Fields on Slow and Fast Skeletal Muscle Atrophy Induced by Streptozotocin: A Preclinical Study

Results

Our findings suggest that antioxidants and PMF may alleviate impaired protein synthesis and degradation pathways in skeletal muscle atrophy. PTS showed a positive effect on the anabolic pathway, while RSV and PMF demonstrated potential for ameliorating the catabolic pathway. Notably, the combination therapy of antioxidants and PMF exhibited a stronger ameliorative effect on skeletal muscle atrophy than either intervention alone.

Conclusion

The present results highlight the benefits of employing a multimodal approach, involving both antioxidant and PMF therapy, for the management of muscle-wasting conditions. These treatments may have potential therapeutic implications for skeletal muscle atrophy.

Resveratrol as a potential protective compound against skeletal muscle insulin resistance

The increasing prevalence of type 2 diabetes has become a major global problem. Insulin resistance has a central role in pathophysiology of type 2 diabetes. Skeletal muscle is responsible for the disposal of most of the glucose under conditions of insulin stimulation, and insulin resistance in skeletal muscle causes dysregulation of glucose homeostasis in the whole body. Despite the current pharmaceutical and non-pharmacological treatment strategies to combat diabetes, there is still a need for new therapeutic agents due to the limitations of the therapeutic agents. Meanwhile, plant polyphenols have attracted the attention of researchers for their use in the treatment of diabetes and have gained popularity. Resveratrol, a stilbenoid polyphenol, exists in various plant sources, and a growing body of evidence suggests its beneficial properties, including antidiabetic activities. The present review aimed to provide a summary of the role of resveratrol in insulin resistance in skeletal muscle and its related mechanisms. To achieve the objectives, by searching the PubMed, Scopus and Web of Science databases, we have summarized the results of all cell culture, animal, and human studies that have investigated the effects of resveratrol in different models on insulin resistance in skeletal muscle.

Proteoglycan Extracted from Ganoderma lucidum Ameliorated Diabetes-Induced Muscle Atrophy via the AMPK/SIRT1 Pathway In Vivo and In Vitro

Muscle atrophy often occurs in type 2 diabetes (T2D) and leads to an increase in physical disability and insulin resistance. However, there are very few studies that have investigated potential natural products used for this condition. In this study, we demonstrated that FYGL (Fudan-Yueyang-G. lucidum), a proteoglycan extracted from Ganoderma lucidum, ameliorated muscle atrophy in rat and mouse models of diabetes. Histopathological analysis of muscle revealed that oral administration of FYGL significantly prevented reduction of the cross-sectional area of muscle fibers and overexpression of muscle atrophic factors in diabetic rats and mice. Muscle RNA-seq analysis in vivo indicated that FYGL regulated genes related to myogenesis, muscle atrophy, and oxidative phosphorylation. Also, FYGL activated AMPK in vivo. Furthermore, the underlying molecular mechanisms were studied in palmitate-induced C2C12 muscle cells using immunofluorescence staining and Western blotting, which revealed that FYGL inhibited muscle atrophy by stimulating ATP production and activating the AMPK/SIRT1 pathway, thus promoting oxidative metabolism. This result rationalized the in vivo findings. These results suggest FYGL as a promising functional food ingredient for the prevention of T2D-induced muscle atrophy.

The effect of endocrine-disrupting chemicals on placental development

Endocrine-disrupting chemicals (EDCs) or endocrine disruptors are substances that are either naturally occurring or artificial and are released into the natural environment. Humans are exposed to EDCs through ingestion, inhalation, and skin contact. Many everyday household items, such as plastic bottles and containers, the liners of metal food cans, detergents, flame retardants, food, gadgets, cosmetics, and pesticides, contain endocrine disruptors. Each hormone has a unique chemical makeup and structural attributes. The way that endocrine hormones connect to receptors is described as a "lock and key" mechanism, with each hormone serving as the key (lock). This mechanism is enabled by the complementary shape of receptors to their hormone, which allows the hormone to activate the receptors. EDCs are described as exogenous chemicals or compounds that have a negative impact on organisms' health by interacting with the functioning of the endocrine system. EDCs are associated with cancer, cardiovascular risk, behavioural disorders, autoimmune abnormalities, and reproductive disorders. EDCs exposure in humans is highly harmful during critical life stages. Nonetheless, the effect of EDCs on the placenta is often underestimated. The placenta is especially sensitive to EDCs due to its abundance of hormone receptors. In this review, we evaluated the most recent data on the effects of EDCs on placental development and function, including heavy metals, plasticizers, pesticides, flame retardants, UV filters and preservatives. The EDCs under evaluation have evidence from human biomonitoring and are found in nature. Additionally, this study indicates important knowledge gaps that will direct future research on the topic.

Resveratrol Ameliorates Hyperglycemic Cultured Cells and Inhibits the Rheb/mTOR Interaction

Resveratrol (RSV) is a natural polyphenol with anti-diabetic effects and has been reported to ameliorate diabetes-induced metabolic disorders through regulating activities of the mTOR signaling pathway. To delineate the effects of RSV treatment on the mTOR signaling pathway, hyperglycemic HepG2 cells were used for the following experiments. Cellular glucose uptake assays showed that high-glucose levels in the culture medium decelerate the glucose uptake of cultured cells. Co-immunoprecipitation showed that high-glucose culture promotes the interaction between mTOR and Rheb-GTP, which is the active form of Rheb. RSV treatment of the cells suppressed this interaction and accelerated the glucose uptake. Western blotting revealed that RSV down-regulated members of the mTOR signaling pathway, namely SREBP1, p70, and S6. Additionally, RSV ameliorated the metabolic disorders, including the decreased levels of AMPK, glycogen synthase, and glucose-6-phosphatase, in hyperglycemic HepG2 cells. These results indicate that RSV inhibits the Rheb/mTOR interaction and ameliorates metabolic disorders associated with high-glucose levels.

Fibroblasts Drive Metabolic Reprogramming in Pacemaker Cardiomyocytes

BACKGROUND

The sinoatrial node (SAN) is characterized by the microenvironment of pacemaker cardiomyocytes (PCs) encased with fibroblasts. An altered microenvironment leads to rhythm failure. Operable cell or tissue models are either generally lacking or difficult to handle. The biological process behind the milieu of SANs to evoke pacemaker rhythm is unknown. We explored how fibroblasts interact with PCs and regulate metabolic reprogramming and rhythmic activity in the SAN.

METHODS

Tbx18 (T-box transcription factor 18)-induced PCs and fibroblasts were used for cocultures and engineered tissues, which were used as the in vitro models to explore how fibroblasts regulate the functional integrity of SANs. RNA-sequencing, metabolomics, and cellular and molecular techniques were applied to characterize the molecular signals underlying metabolic reprogramming and identify its critical regulators. These pathways were further validated in vivo in rodents and induced human pluripotent stem cell-derived cardiomyocytes.

RESULTS

We observed that rhythmicity in Tbx18-induced PCs was regulated by aerobic glycolysis. Fibroblasts critically activated metabolic reprogramming and aerobic glycolysis within PCs, and, therefore, regulated pacemaker activity in PCs. The metabolic reprogramming was attributed to the exclusive induction of Aldoc (aldolase c) within PCs after fibroblast-PC integration. Fibroblasts activated the integrin-dependent mitogen-activated protein kinase-E2F1 signal through cell-cell contact and turned on Aldoc expression in PCs. Interruption of fibroblast-PC interaction or Aldoc knockdown nullified electrical activity. Engineered Tbx18-PC tissue sheets were generated to recapitulate the microenvironment within SANs. Aldoc-driven rhythmic machinery could be replicated within tissue sheets. Similar machinery was faithfully validated in de novo PCs of adult mice and rats, and in human PCs derived from induced pluripotent stem cells.

CONCLUSIONS

Fibroblasts drive Aldoc-mediated metabolic reprogramming and rhythmic regulation in SANs. This work details the cellular machinery behind the complex milieu of vertebrate SANs and opens a new direction for future therapy.

Oxidative Stress, Inflammation and Connexin Hemichannels in Muscular Dystrophies

Muscular dystrophies (MDs) are a heterogeneous group of congenital neuromuscular disorders whose clinical signs include myalgia, skeletal muscle weakness, hypotonia, and atrophy that leads to progressive muscle disability and loss of ambulation. MDs can also affect cardiac and respiratory muscles, impairing life-expectancy. MDs in clude Duchenne muscular dystrophy, Emery-Dreifuss muscular dystrophy, facioscapulohumeral muscular dystrophy and limb-girdle muscular dystrophy. These and other MDs are caused by mutations in genes that encode proteins responsible for the structure and function of skeletal muscles, such as components of the dystrophin-glycoprotein-complex that connect the sarcomeric-actin with the extracellular matrix, allowing contractile force transmission and providing stability during muscle contraction. Consequently, in dystrophic conditions in which such proteins are affected, muscle integrity is disrupted, leading to local inflammatory responses, oxidative stress, Ca²⁺-dyshomeostasis and muscle degeneration. In this scenario, dysregulation of connexin hemichannels seem to be an early disruptor of the homeostasis that further plays a relevant role in these processes. The interaction between all these elements constitutes a positive feedback loop that contributes to the worsening of the diseases. Thus, we discuss here the interplay between inflammation, oxidative stress and connexin hemichannels in the progression of MDs and their potential as therapeutic targets.

Uremic Sarcopenia

"Uremic sarcopenia" refers to a progressive decrease in muscle mass, strength, and function despite normal skeletal muscle physiology in patients with chronic kidney disease (CKD). Sarcopenia involves multiple risk factors, comprising immunological changes, hormonal, metabolic acidosis, reduced protein intake, and physical inactivity. All these risk factors, along with complex pathophysiological mechanisms including ubiquitin, insulin/IGF-1, myostatin, and indoxyl sulfate, activate downstream pathways that ultimately increase muscle degradation while reducing muscle regeneration. Uremic sarcopenia not only affects the quality of life but also increases the risk of morbidity and mortality in patients with CKD. Of all the treatment modalities, aerobic and resistance exercise have shown prevention and reduced rate of muscle degeneration. A variety of pharmacological agents have been tried to target different steps in the known pathogenetic pathways, including the use of androgens and anabolic steroids, correction of vitamin D deficiency, use of growth hormone supplementation, and suppression of the ubiquitin pathway. Though some of these techniques have had beneficial results in animal experiments, human trials are still sparse. This review article relates to recent publications that describe the abnormalities in skeletal muscle that primarily leads to muscle wasting and its consequences in patients with CKD.

Polyphenols as Caloric Restriction Mimetics Regulating Mitochondrial Biogenesis and Mitophagy

The tight coordination between mitochondrial biogenesis and mitophagy can be dysregulated during aging, critically influencing whole-body metabolism, health, and lifespan. To date, caloric restriction (CR) appears to be the most effective intervention strategy to improve mitochondrial turnover in aging organisms. The development of pharmacological mimetics of CR has gained attention as an attractive and potentially feasible approach to mimic the CR phenotype. Polyphenols, ubiquitously present in fruits and vegetables, have emerged as well-tolerated CR mimetics that target mitochondrial turnover. Here, we discuss the molecular mechanisms that orchestrate mitochondrial biogenesis and mitophagy, and we summarize the current knowledge of how CR promotes mitochondrial maintenance and to what extent different polyphenols may mimic CR and coordinate mitochondrial biogenesis and clearance.

Efficacy and Safety of Resveratrol in Type 1 Diabetes Patients: A Two-Month Preliminary Exploratory Trial

Resveratrol has been reported to be beneficial against diabetes complications. The objective of this study was to evaluate the efficacy of resveratrol in decreasing hyperglycemia in patients with type 1 diabetes (T1D) by a preliminary investigation designed as an exploratory clinical trial. Thirteen patients with T1D from both the sexes participated in this trial. All patients received resveratrol in 500 mg capsules, twice daily for 60 days. Bodyweight, fasting blood sugar (FBS), hemoglobin A1c (HbA1c), insulin, homeostasis model of assessment for insulin resistance (HOMA-IR), homeostasis model of assessment for β-cell function (HOMA-β), and markers of liver and kidney damage, inflammation, and oxidative stress were measured before the intervention, at 30 days and at 60 days. Resveratrol supplementation for 60 days significantly decreased FBS and HbA1c in comparison with the baseline values. Resveratrol treatment also resulted in a decrease in the level of a marker for oxidative stress, malondialdehyde, and an increase in total antioxidant capacity in T1D patients. Insulin, HOMA-IR, HOMA-β, and markers of liver and kidney function and inflammation were not significantly affected by resveratrol treatment. Overall, the results showed that 60 days of resveratrol supplementation exerted strong antidiabetic and antioxidant effects in patients with T1D.

The Effect of Resveratrol Supplementation on Cardio-Metabolic Risk Factors in Patients with Type 2 Diabetes: A Randomized, Double-Blind Controlled Trial

The aim of the present randomized controlled trial was to evaluate the effect of a micronized resveratrol supplement on glycemic status, lipid profile, and body composition in patients with type 2 diabetes mellitus (T2DM). A total of 71 overweight patients with T2DM (body mass index ranged 25-30) were randomly assigned to receive 1000 mg/day trans-resveratrol or placebo (methyl cellulose) for 8 weeks. Anthropometric indices and biochemical indices including lipid and glycemic profile were measured before and after the intervention. In adjusted model (age, sex, and baseline body mass index), resveratrol decreased fasting blood sugar (-7.97±13.6 mg/dL, p=0.05) and increased high density lipoprotein (3.62±8.75 mg/dL, p=0.01) levels compared with placebo. Moreover, the mean difference in insulin levels reached significance (-0.97±1.91, μIU/mL, p= 0.02). However, no significant differences were observed for anthropometric measures. It was found that 8-week resveratrol supplementation produced useful effects on some cardio-metabolic parameters in patients with T2DM. More studies are needed to confirm these findings.

Cachexia/Protein energy wasting syndrome in CKD: Causation and treatment

Cachexia is a multifactorial syndrome defined by significant body weight loss, fat and muscle mass reduction, and increased protein catabolism. Protein energy wasting (PEW) is characterized as a syndrome of adverse changes in nutrition and body composition being highly prevalent in patients with CKD, especially in those undergoing dialysis, and it is associated with high morbidity and mortality in this population. Multiple mechanisms are involved in the genesis of these adverse nutritional changes in CKD patients. There is no obvious distinction between PEW and cachexia from a pathophysiologic standpoint and should be considered as part of the spectrum of the same nutritional disorder in CKD with similar management approaches for prevention and treatment based on current understanding. A plethora of factors can affect the nutritional status of CKD patients requiring a combination of therapeutic approaches to prevent or reverse protein and energy depletion. At present, there is no effective pharmacologic intervention that prevents or attenuates muscle atrophy in catabolic conditions like CKD. Prevention and treatment of uremic muscle wasting involve optimal nutritional support, correction of acidosis, and physical exercise. There has been emerging consistent evidence that active treatment, perhaps by combining nutritional interventions and resistance exercise, may be able to improve but not totally reverse or prevent the supervening muscle wasting and weakness. Active research into more direct pharmacological treatment based on basic mechanistic research is much needed for this unmet medical need in patients with CKD.

Resveratrol: A miraculous natural compound for diseases treatment

Resveratrol (3, 5, 4'-trihydroxystilbene) is a nonflavonoid polyphenol that naturally occurs as phytoalexin. It is produced by plant sources such as grapes, apples, blueberries, plums, and peanut. This compound has critical roles in human health and is well known for its diverse biological activities such as antioxidant and anti-inflammatory properties. Nowadays, due to rising incidence of different diseases such as cancer and diabetes, efforts to find novel and effective disease-protective agents have led to the identification of plant-derived compounds such as resveratrol. Furthermore, several in vitro and in vivo studies have revealed the effectiveness of resveratrol in various diseases such as diabetes mellitus, cardiovascular disease, metabolic syndrome, obesity, inflammatory, neurodegenerative, and age-related diseases. This review presents an overview of currently available studies on preventive properties and essential molecular mechanisms involved in various diseases.

Preventative effects of resveratrol and estradiol on streptozotocin-induced diabetes in ovariectomized mice and the related mechanisms

Resveratrol, a non-flavonoid polyphenolic compound, is structurally and functionally similar to estrogen and has drawn great attention for its potentially beneficial effects on diabetes. However, it is not known whether it shares the same protective effect against diabetes as estrogen and the underlying mechanisms. The aim of the present study was to investigate the protective effects of phytoestrogen resveratrol and exogenous 17β-estradiol against streptozotocin (STZ)-induced type 1 diabetes. Female mice were ovariectomized (OVX) and chronically injected with different concentrations of resveratrol (0.1, 1 or 10 mg/kg) and 17β-estradiol (0.01, 0.1 or 1 mg/kg) subcutaneously for 4 weeks, and the levels of blood glucose, plasma insulin, plasma antioxidant capacity, the changes of pancreatic islet cells and the expressions of glucose transporter 4 (GLUT4), insulin receptor substrate 1 (IRS-1) and phosphorylation of extracellular signal-regulated kinase (p-ERK) were detected. Resveratrol and 17β-estradiol significantly inhibited the increase of the blood glucose level and the rise of plasma malondialdehyde in STZ-induced diabetic mice, improved the levels of plasma antioxidant capacity and plasma insulin, protected the pancreatic islet cells, and increased the expressions of GLUT4 and IRS-1, but decreased p-ERK expression in skeletal muscle and myocardial tissue. The results suggest that resveratrol or 17β-estradiol shows obvious protection against STZ-induced diabetes in OVX mice, the mechanisms probably involve their ameliorating antioxidant activities and islet function, promoting muscle glucose uptake and inhibiting the expression of p-ERK.

Dietary Leucine Supplement Ameliorates Hepatic Steatosis and Diabetic Nephropathy in db/db Mice

Dietary leucine supplementation has been explored for the therapeutic intervention of obesity and obesity-induced metabolic dysfunctions. In this study, we aim to examine the effects of dietary leucine supplementation in db/db mice. Mice were treated with or without leucine (1.5% w/v) in drinking water for 12 weeks. The leucine supplement was found to reduce insulin resistance and hepatic steatosis in db/db mice. Using Nuclear Magnetic Resonance (NMR)-based lipidomics, we found that the reduction of hepatic triglyceride synthesis was correlated with attenuated development of fatty liver. In addition, diabetic nephropathy (DN) was also ameliorated by leucine. Using liquid chromatography–time-of-flight mass spectrometry (LC-TOF MS)-based urine metabolomics analysis, we found that the disturbance of the tricarboxylic acid (TCA) cycle was reversed by leucine. The beneficial effects of leucine were probably due to AMP-activated protein kinase (AMPK) activation in the liver and kidneys of db/db mice. Thus, dietary leucine supplementation may potentially be a nutritional intervention to attenuate hepatic steatosis and early DN in type II diabetes.

Activation of AMPK in Human Placental Explants Impairs Mitochondrial Function and Cellular Metabolism

OBJECTIVE

Adenosine monophosphate-activated protein kinase (AMPK) is a cellular energy sensor whose phosphorylation increases energy production. We sought to evaluate the placenta-specific effect of AMPK activation on the handling of nutrients required for fetal development.

METHODS

Explants were isolated from term placenta of 29 women (pregravid body mass index: 29.1 ± 9.9 kg/m²) and incubated for 24 hours with 0 to 100 µmol/L resveratrol or 0 to 1 mmol/L of 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR). Following treatment, uptake and metabolism of radiolabeled fatty acids and glucose were measured. Phosphorylation of AMPK was measured by Western blotting. Adenosine diphosphate (ATP) production was assessed using the mitochondrial ToxGlo assay kit. P < .05 was considered statistically significant.

RESULTS

Resveratrol and AICAR increased AMPK phosphorylation in human placental explants. Exposure to resveratrol decreased the uptake of polyunsaturated fatty acids, arachidonic acid, and docosahexaenoic acid at 100 µmol/L ( P < .0001). Fatty acid oxidation was decreased by 100 µmol/L ( P < .05) resveratrol, while esterification was unchanged. Resveratrol decreased glucose uptake at the 50 and 100 µmol/L doses ( P < .05). Glycolysis was not significantly affected. AICAR had similar effects, decreasing fatty acid uptake and glycolysis ( P < .05). Production of ATP declined at doses found to decrease nutrient metabolism ( P < .05).

CONCLUSIONS

Activation of AMPK in the human placenta leads to global downregulation of metabolism, with mitotoxicity induced at the doses of resveratrol and AICAR used to activate AMPK. Although activation of this pathway has positive metabolic effects on other tissues, in the placenta there is potential for harm, as inadequate placental delivery of critical nutrients may compromise fetal development.

Linalyl acetate restores endothelial dysfunction and hemodynamic alterations in diabetic rats exposed to chronic immobilization stress

Although stress is one of the risk factors of diabetes, few studies have assessed the effects of stress on diabetic rats. This study, therefore, analyzed differences in cardiovascular-related factors among control, nonstressed diabetic, and stressed diabetic rats as well as assessed the effects of linalyl acetate (LA) on stressed diabetic rats. Male Sprague-Dawley rats were subjected to immobilization stress throughout the experimental period, and diabetes was induced on day 15 by a single injection of streptozotocin. After confirming the induction of diabetes, stressed diabetic rats were administered LA (10 or 100 mg/kg) or metformin (500 mg/kg) for the last 7 days. Compared with nonstressed diabetic rats, stressed diabetic rats had significantly lower body weight, body fat percentage, ACh-induced vasorelaxation, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and NF-κB expression as well as increased serum nitrite concentration. Although metformin increased serum insulin concentration significantly, 100 mg/kg LA showed only an increasing tendency. However, treatment with 100 mg/kg LA not only reduced serum glucose and NF-κB expression, but also restored ACh-induced vasorelaxation, SBP, DBP, HR, AMP-activated protein kinase expression, and serum nitrite almost to control levels. Importantly, 100 mg/kg LA was more effective than metformin in ameliorating serum glucose, endothelial nitric oxide synthase expression, HR, and serum nitrite. These findings suggest that chronic stress can aggravate endothelial dysfunction and hemodynamic alterations in diabetes and that LA may have potent therapeutic efficacy in diabetic patients with cardiovascular disease complications or chronic stress.

NEW & NOTEWORTHY To our knowledge, this is the first study to assess the effects of linalyl acetate (LA) on cardiovascular-related factors in diabetic rats exposed to chronic stress. Treatment with LA restored acetylcholine-induced vasorelaxation, blood pressure, heart rate, and AMP-activated protein kinase and serum nitrite levels. The present results suggest that LA may have potent therapeutic efficacy in diabetic patients with complications of cardiovascular disease or chronic stress.

Resveratrol Improves Muscle Atrophy by Modulating Mitochondrial Quality Control in STZ-Induced Diabetic Mice

SCOPE

In this study, we aim to determine the effects of resveratrol (RSV) on muscle atrophy in streptozocin-induced diabetic mice and to explore mitochondrial quality control (MQC) as a possible mechanism.

METHODS AND RESULTS

The experimental mice were fed either a control diet or an identical diet containing 0.04% RSV for 8 weeks. Examinations were subsequently carried out, including the effects of RSV on muscle atrophy and muscle function, as well as on the signaling pathways related to protein degradation and MQC processes. The results show that RSV supplementation improves muscle atrophy and muscle function, attenuates the increase in ubiquitin and muscle RING-finger protein-1 (MuRF-1), and simultaneously attenuates LC3-II and cleaved caspase-3 in the skeletal muscle of diabetic mice. Moreover, RSV treatment of diabetic mice results in an increase in mitochondrial biogenesis and inhibition of the activation of mitophagy in skeletal muscle. RSV also protects skeletal muscle against excess mitochondrial fusion and fission in the diabetic mice.

CONCLUSION

The results suggest that RSV ameliorates diabetes-induced skeletal muscle atrophy by modulating MQC.

Identifying diseases-related metabolites using random walk

Background

Metabolites disrupted by abnormal state of human body are deemed as the effect of diseases. In comparison with the cause of diseases like genes, these markers are easier to be captured for the prevention and diagnosis of metabolic diseases. Currently, a large number of metabolic markers of diseases need to be explored, which drive us to do this work.

Methods

The existing metabolite-disease associations were extracted from Human Metabolome Database (HMDB) using a text mining tool NCBO annotator as priori knowledge. Next we calculated the similarity of a pair-wise metabolites based on the similarity of disease sets of them. Then, all the similarities of metabolite pairs were utilized for constructing a weighted metabolite association network (WMAN). Subsequently, the network was utilized for predicting novel metabolic markers of diseases using random walk.

Results

Totally, 604 metabolites and 228 diseases were extracted from HMDB. From 604 metabolites, 453 metabolites are selected to construct the WMAN, where each metabolite is deemed as a node, and the similarity of two metabolites as the weight of the edge linking them. The performance of the network is validated using the leave one out method. As a result, the high area under the receiver operating characteristic curve (AUC) (0.7048) is achieved. The further case studies for identifying novel metabolites of diabetes mellitus were validated in the recent studies.

Conclusion

In this paper, we presented a novel method for prioritizing metabolite-disease pairs. The superior performance validates its reliability for exploring novel metabolic markers of diseases.

Novel treatment strategies for chronic kidney disease: insights from the animal kingdom

Many of the >2 million animal species that inhabit Earth have developed survival mechanisms that aid in the prevention of obesity, kidney disease, starvation, dehydration and vascular ageing; however, some animals remain susceptible to these complications. Domestic and captive wild felids, for example, show susceptibility to chronic kidney disease (CKD), potentially linked to the high protein intake of these animals. By contrast, naked mole rats are a model of longevity and are protected from extreme environmental conditions through mechanisms that provide resistance to oxidative stress. Biomimetic studies suggest that the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) offers protection in extreme environmental conditions and promotes longevity in the animal kingdom. Similarly, during months of fasting, immobilization and anuria, hibernating bears are protected from muscle wasting, azotaemia, thrombotic complications, organ damage and osteoporosis - features that are often associated with CKD. Improved understanding of the susceptibility and protective mechanisms of these animals and others could provide insights into novel strategies to prevent and treat several human diseases, such as CKD and ageing-associated complications. An integrated collaboration between nephrologists and experts from other fields, such as veterinarians, zoologists, biologists, anthropologists and ecologists, could introduce a novel approach for improving human health and help nephrologists to find novel treatment strategies for CKD.

Resveratrol attenuates skeletal muscle atrophy induced by chronic kidney disease via MuRF1 signaling pathway

Skeletal muscle atrophy is an important clinical characteristic of chronic kidney disease (CKD); however, at present, the therapeutic approaches to muscle atrophy induced by CKD are still at an early stage of development. Resveratrol is used to attenuate muscle atrophy in other experimental models, but the effects on a CKD model are largely unknown. Here, we showed that resveratrol prevented an increase in MuRF1 expression and attenuated muscle atrophy in vivo model of CKD. We also found that phosphorylation of NF-κB was inhibited at the same time. Dexamethasone-induced MuRF1 upregulation was significantly attenuated in C2C12 myotubes by resveratrol in vitro, but this effect on C2C12 myotubes was abrogated by a knockdown of NF-κB, suggesting that the beneficial effect of resveratrol was NF-κB dependent. Our findings provide novel information about the ability of resveratrol to prevent or treat muscle atrophy induced by CKD.

Resveratrol improves glycemic control in insulin-treated diabetic rats: participation of the hepatic territory

BACKGROUND

Resveratrol is a natural polyphenol that has been proposed to improve glycemic control in diabetes, by mechanisms that involve improvement in insulin secretion and activity. In type 1 diabetes (T1D), in which insulin therapy is obligatory, resveratrol treatment has never been investigated. The present study aimed to evaluate resveratrol as an adjunctive agent to insulin therapy in a T1D-like experimental model.

METHODS

Rats were rendered diabetic by streptozotocin (STZ) treatment. Twenty days later, four groups of animals were studied: non-diabetic (ND); diabetic treated with placebo (DP); diabetic treated with insulin (DI) and diabetic treated with insulin plus resveratrol (DIR). After 30 days of treatment, 24-hour urine was collected; then, blood, soleus muscle, proximal small intestine, renal cortex and liver were sampled. Specific glucose transporter proteins were analyzed (Western blotting) in each territory of interest. Solute carrier family 2 member 2 (Slc2a2), phosphoenolpyruvate carboxykinase (Pck1) and glucose-6-phosphatase catalytic subunit (G6pc) mRNAs (qPCR), glycogen storage and sirtuin 1 (SIRT1) activity were analyzed in liver.

RESULTS

Diabetes induction increased blood glucose, plasma fructosamine concentrations, and glycosuria. Insulin therapy partially recovered the glycemic control; however, resveratrol as adjunctive therapy additionally improved glycemic control and restored plasma fructosamine concentration to values of non-diabetic rats. Resveratrol did not alter the expression of the glucose transporters GLUT2 and SGLT1 in the intestine, GLUT2 and SGLT2 in kidney and GLUT4 in soleus, suggesting that fluxes of glucose in these territories were unaltered. Differently, in liver, resveratrol promoted a reduction in Slc2a2, Pck1, and G6pc mRNAs, as well as in GLUT2 protein (P < 0.05, DIR vs. DI); besides, it increased (P < 0.01, DIR vs. DI) the hepatic glycogen content, and SIRT1 protein.

CONCLUSIONS

Resveratrol is able to improve glycemic control in insulin-treated T1D-like rats. This effect seems not to involve changes in glucose fluxes in the small intestine, renal proximal tubule, and soleus skeletal muscle; but to be related to several changes in the liver, where downregulation of Slc2a2/GLUT2, Pck1, and G6pc expression was observed, favoring reduction of glucose production and efflux. Besides, resveratrol increased SIRT1 nuclear protein content in liver, which may be related to the observed gene expression regulations.

Dietary supplementation with shiikuwasha extract attenuates dexamethasone-induced skeletal muscle atrophy in aged rats

Background

Skeletal muscle atrophy is caused by a variety of diseases and conditions. In particular, skeletal muscle atrophy in the elderly contributes to a loss of independence with advanced age and increases the risk of falling. However, the effect of food consumed on a daily basis on skeletal muscle atrophy has been the focus of little research. In this study, the effects of dietary supplementation with shiikuwasha extract or grape extract on dexamethasone-induced skeletal muscle atrophy were evaluated in aged rats.

Methods

Aged male rats (15-month-old) were fed a diet supplemented with either 1 % shiikuwasha extract or 1 % grape extract for 19 days. During the last 5 days of the feeding period, rats were injected with dexamethasone to induce muscle atrophy.

Results

Body weight and hind-limb muscle weight were significantly decreased by dexamethasone treatment. The supplementation of shiikuwasha extract showed no effect on body weight loss, but markedly attenuated tibialis anterior muscle weight loss induced by dexamethasone. On the other hand, grape extract did not affect muscle weight loss. Furthermore, shiikuwasha extract significantly reduced dexamethasone-induced expression of atrogin-1 and MuRF1 mRNA, but did not reduce LC3B-II protein levels.

Conclusion

These results suggest that shiikuwasha extract may partially inhibit the activation of the ubiquitin–proteasome system and may consequently attenuate skeletal muscle atrophy induced by dexamethasone in aged rats.

High-fructose and high-fat feeding correspondingly lead to the development of lysoPC-associated apoptotic cardiomyopathy and adrenergic signaling-related cardiac hypertrophy

BACKGROUND

The heart is a highly adaptive organ that demonstrates remarkable structural, functional, and metabolic remodeling in response to physiological and pathological stimuli. We hypothesize that the heart undergoes differential adaptations in high-fat and high-fructose diet, resulting in a distinct phenotype.

METHODS

High-fat and high-fructose diet-induced obese and non-obese insulin resistance (IR) rat models were used to understand how the heart adapts to long-term (12-week) overnutrition.

RESULTS

Rats fed the high-fat diet developed obese IR, whereas high-fructose diet developed non-obese IR. Obese IR rats developed fibrotic hypertrophy with impairment of preload-independent contractility. The sympathetic and renin-angiotensin-aldosterone (RAA) systems and myocardial adrenergic signaling were activated in obese IR rats. Non-obese IR rats developed apoptotic cardiomyopathy with severe systolic dysfunction. Myocardial calcium cycling regulatory proteins (CCRPs) were dysregulated in non-obese IR rats; specifically, troponin I protein expression was downregulated. Moreover, compared with the controls, lipidomics analysis revealed substantial differences in lipid metabolites in non-obese IR and obese IR rats. The overproduction of lysophosphatidylcholine (lysoPC) and fatty acids was observed in non-obese IR rat hearts. A strong correlation was observed between the myocardial lysoPC and plasma troponin I levels. Treatment of cardiomyocytes with lysoPC resulted in cell death in a dose- and time-dependent manner. The overproduction of myocardial lysoPCs was associated with circulating sPLA2 levels.

CONCLUSION

Obese IR rats developed severe fibrotic hypertrophy with the activation of adrenergic signaling and sympathetic and RAA systems. The sPLA2-lysoPC may play a crucial role in the induction of apoptotic cardiomyopathy in high fructose-induced non-obese IR rats.

Resveratrol shows neuronal and vascular-protective effects in older, obese, streptozotocin-induced diabetic rats

Diabetes-induced CVD is the most significant complication of prolonged hyperglycaemia. The aim of this study was to determine whether resveratrol, a polyphenol antioxidant compound, when administered at a dose that can be reasonably obtained through supplementation could prevent the development of cardiovascular complications in older, obese, diabetic rats. Diabetes was induced in 6-month old, obese, male Wistar rats via a single intravenous dose of streptozotocin (65 mg/kg). Randomly selected animals were administered resveratrol (2 mg/kg) via oral gavage daily for 8 weeks. Body weights, blood glucose levels, food intake and water consumption were monitored, and assessments of vascular reactivity, tactile allodynia and left ventricular function were performed. Resveratrol therapy significantly improved tactile allodynia and vascular contractile functionality in diabetic rats (P<0·05). There were no significant changes in standardised vasorelaxation responses, plasma glucose concentrations, water consumption, body weight, left ventricular hypertrophy, kidney hypertrophy, heart rate or left ventricular compliance with resveratrol administration. Resveratrol-mediated improvements in vascular and nerve function in old, obese, diabetic rats were associated with its reported antioxidant effects. Resveratrol did not improve cardiac function nor mitigate the classic clinical symptoms of diabetes mellitus (i.e. hyperglycaemia, polydypsia and a failure to thrive). This suggests that supplementation with resveratrol at a dose achievable with commercially available supplements would not produce significant cardioprotective effects in people with diabetes mellitus.

Resveratrol and the mitochondria: From triggering the intrinsic apoptotic pathway to inducing mitochondrial biogenesis, a mechanistic view

BACKGROUND

Mitochondria, the power plants of the cell, are known as a cross-road of different cellular signaling pathways. These cytoplasmic double-membraned organelles play a pivotal role in energy metabolism and regulate calcium flux in the cells. It is well known that mitochondrial dysfunction is associated with different diseases such as neurodegeneration and cancer. A growing body of literature has shown that polyphenolic compounds exert direct effects on mitochondrial ultra-structure and function. Resveratrol is known as one of the most common bioactive constituents of red wine, which improves mitochondrial functions under in vitro and in vivo conditions.

SCOPE OF REVIEW

This paper aims to review the molecular pathways underlying the beneficial effects of resveratrol on mitochondrial structure and functions. In addition, we discuss the chemistry and main sources of resveratrol.

MAJOR CONCLUSIONS

Resveratrol represents the promising effects on mitochondria in different experimental models. However, there are several reports on the detrimental effects elicited by resveratrol on mitochondria.

GENERAL SIGNIFICANCE

An understanding of the chemistry and source of resveratrol, its bioavailability and the promising effects on mitochondria brings a new hope to therapy of mitochondrial dysfunction-related diseases.

Antidiabetic Effects of Resveratrol: The Way Forward in Its Clinical Utility

Despite recent advances in the understanding and management of diabetes mellitus, the prevalence of the disease is increasing unabatedly with resulting disabling and life-reducing consequences to the global human population. The limitations and side effects associated with current antidiabetic therapies have necessitated the search for novel therapeutic agents. Due to the multipathogenicity of diabetes mellitus, plant-derived compounds with proven multiple pharmacological actions have been postulated to "hold the key" in the search for an affordable, efficacious, and safer therapeutic agent in the treatment of the disease and associated complications. Resveratrol, a phytoalexin present in few plant species, has demonstrated beneficial antidiabetic effects in animals and humans through diverse mechanisms and multiple molecular targets. However, despite the enthusiasm and widespread successes achieved with the use of resveratrol in animal models of diabetes mellitus, there are extremely limited clinical data to confirm the antidiabetic qualities of resveratrol. This review presents an update on the mechanisms of action and protection of resveratrol in diabetes mellitus, highlights challenges in its clinical utility, and suggests the way forward in translating the promising preclinical data to a possible antidiabetic drug in the near future.

Plasma metabolite profiles following trauma-hemorrhage: effect of posttreatment with resveratrol

Resveratrol (RSV) has been shown to inhibit the inflammatory reaction and ameliorate the organ damage resulting from trauma-hemorrhage (TH). However, the effects of RSV on the metabolomic profiles under these conditions remain unclear. The aim of this study was to determine the metabolomic profiles of plasma in TH rats and to evaluate the therapeutic effects of RSV using high-performance liquid chromatography-mass spectrometry. Thirty male Sprague-Dawley rats were divided into sham operation (n = 10), sham-operation plus RSV treatment (n = 10), TH (n = 10), and TH plus RSV treatment (n = 10) groups. Plasma samples were obtained at 24 h after surgery. Electrospray ionization-tandem mass spectrometry was used to characterize the plasma metabolomes. The systemic analyses of plasma metabolomes and their targets were determined using a number of computational approaches, including principal component analysis, partial least squares discriminant analysis, and heat map analysis. Using these methods, the effects of RSV on the metabolomic profiles in animals that underwent trauma-hemorrhagic injury were determined. These approaches allowed a clear discrimination of the pathophysiological characteristics among the groups. The results demonstrate RSV treatment significantly reduced the metabolic derangements caused by TH. Compared with the sham-operated rats, the plasma levels of carnitine in the TH rats were relatively lower, but the levels of acetylcarnitine and butyrylcarnitine were higher, suggesting that RSV ameliorated the deranged carnitine metabolism in TH rats. There was a statistically significant increase in carnitine. In addition, RSV treatment reduced ketoacidosis and protein degradation, as evidenced by the attenuation of the elevated plasma branched-chain amino acid levels in the TH rats. Our study showed that the alterations of the metabolomic profiles in the rats subjected to trauma-hemorrhagic shock were attenuated by RSV treatment. In view of the metabolomic evidence, we conclude that RSV exerts beneficial effects in trauma-hemorrhagic shock injury and that these effects are partially mediated by improving energy metabolism and reducing protein degradation.

Properties of Resveratrol: In Vitro and In Vivo Studies about Metabolism, Bioavailability, and Biological Effects in Animal Models and Humans

Plants containing resveratrol have been used effectively in traditional medicine for over 2000 years. It can be found in some plants, fruits, and derivatives, such as red wine. Therefore, it can be administered by either consuming these natural products or intaking nutraceutical pills. Resveratrol exhibits a wide range of beneficial properties, and this may be due to its molecular structure, which endow resveratrol with the ability to bind to many biomolecules. Among these properties its activity as an anticancer agent, a platelet antiaggregation agent, and an antioxidant, as well as its antiaging, antifrailty, anti-inflammatory, antiallergenic, and so forth activities, is worth highlighting. These beneficial biological properties have been extensively studied in humans and animal models, both in vitro and in vivo. The issue of bioavailability of resveratrol is of paramount importance and is determined by its rapid elimination and the fact that its absorption is highly effective, but the first hepatic step leaves little free resveratrol. Clarifying aspects like stability and pharmacokinetics of resveratrol metabolites would be fundamental to understand and apply the therapeutic properties of resveratrol.

Muscle wasting in end-stage renal disease promulgates premature death: established, emerging and potential novel treatment strategies

Muscle wasting (or sarcopenia) is a common feature of the uremic phenotype and predisposes this vulnerable patient population to increased risk of comorbid complications, poor quality of life, frailty and premature death. The old age of dialysis patients is in addition a likely contributor to loss of muscle mass. As recent evidence suggests that assessment of muscle strength (i.e. function) is a better predictor of outcome and comorbidities than muscle mass, this opens new screening, assessment and therapeutic opportunities. Among established treatment strategies, the benefit of resistance exercise and endurance training are increasingly recognized among nephrologists as being effective and should be promoted in sedentary chronic kidney disease patients. Testosterone and growth hormone replacement appear as the most promising among emerging treatments strategies for muscle wasting. As treatment of muscle wasting is difficult and seldom successful in this often old, frail, sedentary and exercise-hesitant patient group, novel treatment strategies are urgently needed. In this review, we summarize recent studies on stimulation of mitochondrial biogenesis, myogenic stem (satellite) cells and manipulation of transforming growth factor family members, all of which hold promise for more effective therapies to target muscle mass loss and function in the future.

Resveratrol-Dependent Down-regulation of Receptor for Advanced Glycation End-products and Oxidative Stress in Kidney of Rats With Diabetes

BACKGROUND

Millions of people in the world have diabetes mellitus and its prevalence is growing. Oxidative stress, advanced glycation end-products (AGEs) and receptor for advanced glycation end-products (RAGE) play key role in the pathogenesis of diabetes. New and safe strategies of remedy are needed for this disease.

OBJECTIVES

We hypothesized that resveratrol may exert a renal protective effect on diabetic rats.

MATERIALS AND METHODS

Male rats with diabetes were treated with or without resveratrol as 1, 5, 10 mg/kg of body weight for 30 days. The total AGEs and malondialdehyde levels in kidney tissues were determined by spectrofluorimetric method and the insulin level was assayed using ELISA. The total antioxidant capacity contents in kidney and the glucose in plasma were measured by a colorimetric assay. The expression of RAGE was assayed in kidneys of all animals using quantitative PCR.

RESULTS

In resveratrol-treated rats with diabetes, malondialdehyde levels, plasma glucose and expression of RAGE were significantly reduced compared with the untreated group. Moreover, the total antioxidant and insulin levels significantly increased in treated rats. There was no significant difference in the AGEs contents among all the groups.

CONCLUSIONS

These results revealed that resveratrol has beneficial effects on kidney by extenuating the oxidative stress and down-regulation of RAGE expression.

The pharmacology of resveratrol in animals and humans

In addition to thousands of research papers related to resveratrol (RSV), approximately 300 review articles have been published. Earlier research tended to focus on pharmacological activities of RSV related to cardiovascular systems, inflammation, and carcinogenesis/cancer development. More recently, the horizon has been broadened by exploring the potential effect of RSV on the aging process, diabetes, neurological dysfunction, etc. Herein, we primarily focus on the in vivo pharmacological effects of RSV reported over the past 5 years (2009-2014). In addition, recent clinical intervention studies performed with resveratrol are summarized. Some discrepancies exist between in vivo studies with animals and clinical studies, or between clinical studies, which are likely due to disparate doses of RSV, experimental settings, and subject variation. Nevertheless, many positive indications have been reported with mammals, so it is reasonable to advocate for the conduct of more definitive clinical studies. Since the safety profile is pristine, an added advantage is the use of RSV as a dietary supplement. This article is part of a Special Issue entitled: Resveratrol: Challenges in translating pre-clinical findings to improved patient outcomes.

Metabolomic profiling in cattle experimentally infected with Mycobacterium avium subsp. paratuberculosis

The sensitivity of current diagnostics for Johne's disease, a slow, progressing enteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), is too low to reliably detect all infected animals in the subclinical stage. The objective was to identify individual metabolites or metabolite profiles that could be used as biomarkers of early MAP infection in ruminants. In a monthly follow-up for 17 months, calves infected at 2 weeks of age were compared with aged-matched controls. Sera from all animals were analyzed by 1H nuclear magnetic resonance spectrometry. Spectra were acquired, processed, and quantified for analysis. The concentration of many metabolites changed over time in all calves, but some metabolites only changed over time in either infected or non-infected groups and the change in others was impacted by the infection. Hierarchical multivariate statistical analysis achieved best separation between groups between 300 and 400 days after infection. Therefore, a cross-sectional comparison between 1-year-old calves experimentally infected at various ages with either a high- or a low-dose and age-matched non-infected controls was performed. Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS DA) yielded distinct separation of non-infected from infected cattle, regardless of dose and time (3, 6, 9 or 12 months) after infection. Receiver Operating Curves demonstrated that constructed models were high quality. Increased isobutyrate in the infected cattle was the most important agreement between the longitudinal and cross-sectional analysis. In general, high- and low-dose cattle responded similarly to infection. Differences in acetone, citrate, glycerol and iso-butyrate concentrations indicated energy shortages and increased fat metabolism in infected cattle, whereas changes in urea and several amino acids (AA), including the branched chain AA, indicated increased protein turnover. In conclusion, metabolomics was a sensitive method for detecting MAP infection much sooner than with current diagnostic methods, with individual metabolites significantly distinguishing infected from non-infected cattle.

Resveratrol and diabetes: from animal to human studies

Diabetes mellitus is a serious disease affecting about 5% of people worldwide. Diabetes is characterized by hyperglycemia and impairment in insulin secretion and/or action. Moreover, diabetes is associated with metabolic abnormalities and serious complications. Resveratrol is a natural, biologically active polyphenol present in different plant species and known to have numerous health-promoting effects in both animals and humans. Anti-diabetic action of resveratrol has been extensively studied in animal models and in diabetic humans. In animals with experimental diabetes, resveratrol has been demonstrated to induce beneficial effects that ameliorate diabetes. Resveratrol, among others, improves glucose homeostasis, decreases insulin resistance, protects pancreatic β-cells, improves insulin secretion and ameliorates metabolic disorders. Effects induced by resveratrol are strongly related to the capability of this compound to increase expression/activity of AMPK and SIRT1 in various tissues of diabetic subjects. Moreover, anti-oxidant and anti-inflammatory effects of resveratrol were shown to be also involved in its action in diabetic animals. Preliminary clinical trials show that resveratrol is also effective in type 2 diabetic patients. Resveratrol may, among others, improve glycemic control and decrease insulin resistance. These results show that resveratrol holds great potential to treat diabetes and would be useful to support conventional therapy. This article is part of a Special Issue entitled: Resveratrol: Challenges in translating pre-clincial findigns to improved patient outcomes.

Cardiac energy metabolism and oxidative stress biomarkers in diabetic rat treated with resveratrol

Resveratrol (RSV), polyphenol from grape, was studied to evaluate its effects on calorimetric parameters, energy metabolism, and antioxidants in the myocardium of diabetic rats. The animals were randomly divided into four groups (n = 8): C (control group): normal rats; C-RSV: normal rats receiving RSV; DM: diabetic rats; and DM-RSV: diabetics rats receiving RSV. Type 1 diabetes mellitus was induced with administration of streptozotocin (STZ; 60 mg⁻¹ body weight, single dose, i.p.). After 48 hours of STZ administration, the animals received RSV (1.0 mg/kg/day) for gavage for 30 days. Food, water, and energy intake were higher in the DM group, while administration of RSV caused decreases (p<0.05) in these parameters. The glycemia decreased and higher final body weight increased in DM-RSV when compared with the DM group. The diabetic rats showed higher serum-free fatty acid, which was normalized with RSV. Oxygen consumption (VO₂) and carbon dioxide production (VCO₂) decreased (p<0.05) in the DM group. This was accompanied by reductions in RQ. The C-RSV group showed higher VO₂ and VCO₂ values. Pyruvate dehydrogenase activity was lower in the DM group and normalizes with RSV. The DM group exhibited higher myocardial β-hydroxyacyl coenzyme-A dehydrogenase and citrate synthase activity, and RSV decreased the activity of these enzymes. The DM group had higher cardiac lactate dehydrogenase compared to the DM-RSV group. Myocardial protein carbonyl was increased in the DM group. RSV increased reduced glutathione in the cardiac tissue of diabetic animals. The glutathione reductase activity was higher in the DM-RSV group compared to the DM group. In conclusion, diabetes is accompanied by cardiac energy metabolism dysfunction and change in the biomarkers of oxidative stress. The cardioprotective effect may be mediated through RVS's ability to normalize free fatty acid oxidation, enhance utilization glucose, and control the biomarkers' level of oxidative stress under diabetic conditions.

Serum glycine is associated with regional body fat and insulin resistance in functionally-limited older adults

BACKGROUND

Metabolic profiling may provide insight into biologic mechanisms related to age-related increases in regional adiposity and insulin resistance.

OBJECTIVES

The objectives of the current study were to characterize the association between mid-thigh intermuscular and subcutaneous adipose tissue (IMAT, SCAT, respectively) and, abdominal adiposity with the serum metabolite profile, to identify significant metabolites as further associated with the homeostasis model assessment of insulin resistance (HOMA-IR), and, to develop a HOMA-IR associated metabolite predictor set representative of regional adiposity, in 73 functionally-limited (short physical performance battery ≤10; SPPB) older adults (age range, 70-85 y).

METHODS

Fasting levels of 181 total metabolites, including amino acids, fatty acids and acylcarnitines were measured with use of an untargeted mass spectrometry-based metabolomic approach. Multivariable-adjusted linear regression was used in all analyses.

RESULTS

Thirty-two, seven and one metabolite(s) were found to be associated with IMAT, abdominal adiposity and, SCAT, respectively, including the amino acid glycine, which was positively associated with SCAT and, negatively associated with both IMAT and abdominal adiposity. Glycine and four metabolites found to be significantly associated with regional adiposity were additionally associated with HOMA-IR. Separate stepwise regression models identified glycine as a HOMA-IR associated marker of both IMAT (model R(2) = 0.51, p<0.0001) and abdominal adiposity (model R(2) = 0.41, p<0.0001).

CONCLUSION

Our findings for a positive association between glycine with SCAT but, a negative association between glycine with IMAT and abdominal adiposity supports the hypothesis that SCAT metabolic processes are different from that found in other fat depots. In addition, because of the significant associations found between glycine with HOMA-IR, IMAT, SCAT and abdominal adiposity, our results suggest glycine as a serum biomarker of both insulin sensitivity and regional fat mass in functionally-limited older adults.

Resveratrol: why is it a promising therapy for chronic kidney disease patients?

Resveratrol, a phenolic compound found in various plants, including grapes, berries, and peanuts, shows promise for the treatment of cancer, aging, type 2 diabetes, and cardiovascular diseases. Resveratrol can promote transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) activation, increase the expression level of SIRT-1, which is a sirtuin family protein, and reduce mTOR pathway signaling. This compound has anti-inflammatory properties in that it inhibits or antagonizes the nuclear factor-κB (NF-κB) activity, which is a redox-sensitive transcription factor that coordinates the inflammatory response. Inflammation and oxidative stress, which are common features in patients with chronic kidney disease (CKD), are interrelated and associated with cardiovascular disease and the progression of CKD itself. Because of the modulation of the mechanisms involved in the inflammatory-oxidative stress cycle, resveratrol could play an important role in controlling CKD-related metabolic derangements. Although resveratrol supplementation in theory is a promising therapy in this patient group, there are no studies evaluating its effects. Thus, the present review aims to describe the role of resveratrol in inflammation and oxidative stress modulation and its possible benefits to patients with CKD.

Sesquiterpene lactones and their derivatives inhibit high glucose-induced NF-κB activation and MCP-1 and TGF-β1 expression in rat mesangial cells

Diabetic nephropathy (DN) is one of the most common and serious chronic complications of diabetes mellitus, however, no efficient clinical drugs exist for the treatment of DN. We selected and synthesized several sesquiterpene lactones (SLs), and then used the MTT assay to detect rat mesangial cells (MCs) proliferation, ELISA to measure the expression level of monocyte chemoattractant protein-1 (MCP-1), transforming growth factor beta (TGF-β1) and fibronectin(FN), real-time fluorescent quantitative PCR analysis to measure the MCP-1 and TGF-β1 gene expression, western blot to detect the level of IκBα protein and EMSA to measure the activation of nuclear factor kappa B (NF-κB). We discovered that SLs, including parthenolide (PTL), micheliolide (MCL), arglabin, and isoalantolactone (IAL), as well as several synthetic analogs of these molecules, could effectively attenuate the high glucose-stimulated activation of NF-κB, the degradation of IκBα, and the expression of MCP-1, TGF-β1 and FN in rat mesangial cells (MCs). These findings suggest that SLs and their derivatives have potential as candidate drugs for the treatment of DN.

Nicotinuric acid: a potential marker of metabolic syndrome through a metabolomics-based approach

OBJECTIVE

Metabolic syndrome is a multiplex disorder and puts patients on the road to type 2 diabetes and atherosclerotic cardiovascular diseases. However, a surrogate biomarker in plasma or urine in fully reflecting features of metabolic syndrome has not been explored.

RESEARCH DESIGN AND METHODS

Urine metabolomics has potential utility in metabolic profiling because urine metabolites analysis reflects global outflux of metabolic change. Accordingly, we collected data on subjects (n = 99) with overweight, dyslipidemia, hypertension or impaired glucose tolerance and took a metabolomics approach to analyze the metabolites of urine revealed in metabolic syndrome by high-performance liquid chromatography-time-of-flight mass spectrometry and elicit potential biomarkers to picture metabolic syndrome.

RESULTS

Our results revealed that the urine nicotinuric acid value of subjects with diabetes (HbA1c ≥ 6.5% or those receiving diabetes medications) (n = 25) was higher than subjects without diabetes (n = 37) (221 ± 31 vs. 152 ± 13 × 10(3) mAU, P = 0.0268). Moreover, urinary nicotinuric acid level was positively correlated with body mass index, blood pressure, total cholesterol, low-density lipoprotein cholesterol, triacylglycerol and high sensitivity C-reactive protein, but negatively correlated with high-density lipoprotein cholesterol.

CONCLUSIONS

This is the first study, to our knowledge, to propose that nicotinuric acid represents an important pathogenic mechanism in process from metabolic syndrome to diabetes and atherosclerotic cardiovascular disease.

The Tellurium compound, AS101, increases SIRT1 level and activity and prevents type 2 diabetes

The histone deacetylase, SIRT1, plays a major role in glucose regulation and lipid metabolism. Ammonium Trichloro (dioxoethylene-o,o') Tellurate, AS101, is a potent in vitro and in vivo immunomodulator, with several potential therapeutic applications. AS101 administration resulted in upregulation of SIRT1 protein expression and activity. These effects were associated with decreased levels of serum insulin like growth factor-1 (IGF-1) and of insulin. The properties of AS101 prompted us to investigate its potential therapeutic role in rats with type 2 diabetes (T2D). T2D was induced by a high fat diet combined with a low dose of Streptozotocin (STZ). Treatment with AS101 before manifestation of hyperglycemia, resulted in increased insulin sensitivity, and decreased blood glucose levels, and prevented symptoms of diabetes including defective glucose clearance, fatty liver, and abnormal distribution of insulin-producing beta cells in the pancreas. Treatment after disease emergence resulted in partial restoration of normal glucose homeostasis. Diabetic rats showed a reduction in liver SIRT1 levels. In both treatment regimens the reduction in SIRT1 levels in the liver were blocked by AS101 consumption. Together, these findings demonstrate the therapeutic potential of AS101 for treating T2D, and for reversing impaired fat and glucose metabolism.

Chronic kidney disease: a clinical model of premature aging

Premature aging is a process associated with a progressive accumulation of deleterious changes over time, an impairment of physiologic functions, and an increase in the risk of disease and death. Regardless of genetic background, aging can be accelerated by the lifestyle choices and environmental conditions to which our genes are exposed. Chronic kidney disease is a common condition that promotes cellular senescence and premature aging through toxic alterations in the internal milieu. This occurs through several mechanisms, including DNA and mitochondria damage, increased reactive oxygen species generation, persistent inflammation, stem cell exhaustion, phosphate toxicity, decreased klotho expression, and telomere attrition. Because recent evidence suggests that both increased local signaling of growth factors (through the nutrient-sensing mammalian target of rapamycin) and decreased klotho expression are important modulators of aging, interventions that target these should be tested in this prematurely aged population.

[Resveratrol: distribution, properties and perspectives]

Resveratrol is a natural polyphenol which can be found in many plants and fruits, such as peanuts, mulberries, blueberries and, above all, in grapes and red wine. Its synthesis is regulated by the presence of stressful factors, such as fungal contamination and ultra-violet radiation. In plants, it plays a role as a phytoalexin, showing a capacity to inhibit the development of certain infections. Plant extracts which contain resveratrol have been employed by traditional medicine for more than 2000 years. Resveratrol was first isolated, and its properties were initially studied with scientific methods, thirty years ago. Its in vitro properties have been extensively studied and demonstrated. It is worth highlighting its activity as an anti-cancer agent, platelet anti-aggregation agent, anti-inflammatory, antiallergenic, etc. The activity of its in vivo properties are not so clear. There are many studies that report benefits on the cardiovascular system, illnesses such as diabetes, and in longevity. However, other authors did not find any agreement between in vitro and in vivo studies. This discrepancy is due to the bioavailability of resveratrol. After an oral dose, it has been demonstrated that the absorption is very high, but the metabolic pathways leave just a little free resveratrol in blood, therefore the bioavailability in the target tissues is very low and the concentrations used in in vitro studies are not found in these tissues. Thus, resveratrol is a very active molecule for maintaining health, but due to the low bioavailability not all the in vitro effects can be translated to in vivo. This opens a new potential approach, seeking derivatives of resveratrol that can be measured in the desired tissues.