Triple verses glimepiride plus metformin therapy on cardiovascular risk biomarkers and diabetic cardiomyopathy in insulin resistance type 2 diabetes mellitus rats

Therapeutic effects of Mudan granules on diabetic retinopathy: Mitigating fibrogenesis caused by FBN2 deficiency and inflammation associated with TNF-α elevation

ETHNOPHARMACOLOGICAL RELEVANCE

Mudan granules (MuD), a time-honored traditional Chinese patent medicine (TCPM), are widely utilized in the clinical treatment of diabetic peripheral neuropathy (DPN). In the field of biomedical diagnostics, both diabetic retinopathy (DR) and DPN are recognized as critical microvascular complications associated with diabetes. According to the principles of traditional Chinese medicine (TCM), these conditions are primarily attributed to a deficiency in Qi and the obstruction of collaterals. Despite this, the protective effects of MuD on DR and the underlying mechanisms remain to be comprehensively elucidated.

AIMS OF THE STUDY

The purpose of this study was to investigate the effect of MuD on DR and to further explore the promising therapeutic targets.

METHODS

A diabetic mouse model was established by administering 60 mg/kg of streptozotocin (STZ) via intraperitoneal injection for five consecutive days. The therapeutic efficacy of MuD was evaluated using a comprehensive approach, which included electroretinogram (ERG) analysis, histopathological examination, and assessment of serum biochemical markers. Then, the pharmacodynamic mechanisms of MuD were systematically analyzed using Tandem Mass Tags-based proteomics. Meanwhile, the candidate compounds of MuD were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and molecular docking was applied to estimate the affinity of the active ingredient to their potential key targets. In addition, the functional mechanisms identified through bioinformatics analysis were confirmed by molecular biological methods.

RESULTS

We demonstrated that MuD provided significant protection to retinal function and effectively mitigated the reduction in retinal thickness observed in the animal model. Through proteomic analysis, we identified a substantial regulation by MuD of 70 biomarkers associated with diabetic retinal damage. These proteins were notably enriched in the tumor necrosis factor (TNF) signaling pathway, a critical mediator in inflammatory processes. A particularly intriguing finding was the significant downregulation of fibrillin-2 (FBN2) in the diabetic retina compared to the control group (0.36 times the level), and its most pronounced upregulation (3.26 times) in the MuD treatment group. This suggests that FBN2 may play a pivotal role in the protective effects of MuD. Molecular docking analyses have unveiled a robust interplay between the components of MuD and TNF-α. Further corroboration was provided by molecular biological methods, which confirmed that MuD could suppress TNF-mediated inflammation and prevent retinal neovascularization and fibrogenesis.

CONCLUSION

MuD have the potential to alleviate diabetic retinal dysfunction by effectively curbing the fibrogenesis-associated neoangiogenesis and mitigating the inflammatory response, thereby restoring retinal health and function.

Early detection and progression of insulin resistance revealed by impaired organismal anti-inflammatory heat shock response during ex vivo whole-blood heat challenge

Chronic inflammatory diseases, e.g., obesity, cardiovascular disease and type-2 diabetes, progressively suppress the anti-inflammatory heat shock response (HSR) by impairing the synthesis of key components, perpetuating inflammation. Monitoring HSR progression offers predictive value for countering chronic inflammation. This study quantified HSR in high-fat diet (HFD) and normal chow (NC) mice by measuring 70 kDa heat shock protein (HSP70) expression after heat treatment of whole blood samples. To align with human translational relevance, animals were housed within their thermoneutral zone (TNZ). Whole blood was heat-challenged weekly at 42 °C for 1-2 hours over 22 weeks, and ΔHSP70 was calculated as the difference between HSP70 expressions at 42 °C and 37 °C. Results correlated with fasting glycaemia, oral glucose tolerance test, intraperitoneal insulin tolerance test and 2-hour post-glucose load glycaemia. ΔHSP70 levels >0.2250 indicated normal fasting glycaemia, while levels <0.2125 signalled insulin resistance and type-2 diabetes onset. A logistic model (five-parameter logistic) showed progressive HSR decline, with HFD mice exhibiting earlier ΔHSP70 reduction (t1/2 = 3.14 weeks) compared with NC mice (t1/2 = 8.24 weeks), highlighting compromised anti-inflammatory capacity in both groups of mice maintained at TNZ. Remarkably, even NC mice surpassed insulin resistance thresholds by week 22, relevant as control diets confronted interventions. Observed HSR decline mirrors tissue-level suppression in obese and type-2 diabetic individuals, underscoring HSR failure as a hallmark of obesity-driven inflammation. This study introduces a practical whole-blood assay to evaluate HSR suppression, allowing assessment of glycaemic status during obesity onset before any clinical manifestation.

Tiaogan daozhuo formula attenuates atherosclerosis via activating AMPK -PPARγ-LXRα pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Tiaogan Daozhuo Formula (TGDZF) is a common formulation against atherosclerosis, however, there is limited understanding of its therapeutic mechanism.

AIM OF THIS STUDY

To examine the effectiveness of TGDZF in the treatment of atherosclerosis and to explore its mechanisms.

MATERIALS AND METHODS

In ApoE-/- mice, atherosclerosis was induced by a high-fat diet for 12 weeks and treated with TGDZF at different doses. The efficacy of TGDZF in alleviating atherosclerosis was evaluated by small animal ultrasound and histological methods. Lipid levels were measured by biochemical methods. The capacity of cholesterol efflux was tested with a cholesterol efflux assay in peritoneal macrophage, and the expression of AMPKα1, PPARγ, LXRα, and ABCA1 was examined at mRNA and protein levels. Meanwhile, RAW264.7-derived macrophages were induced into foam cells by ox-LDL, and different doses of TGDZF-conducting serum were administered. Similarly, we examined differences in intracellular lipid accumulation, cholesterol efflux rate, and AMPKα1, PPARγ, LXRα, and ABCA1 levels following drug intervention. Finally, changes in the downstream molecules were evaluated following the inhibition of AMPK by compound C or PPARγ silencing by small interfering RNA.

RESULTS

TGDZF administration reduced aortic plaque area and lipid accumulation in aortic plaque and hepatocytes, and improved the serum lipid profiles of ApoE-/- mice. Further study revealed that its efficacy was accompanied by an increase in cholesterol efflux rate and the expression of PPARγ, LXRα, and ABCA1 mRNA and protein, as well as the promotion of AMPKα1 phosphorylation. Moreover, similar results were caused by the intervention of TGDZF-containing serum in vitro experiments. Inhibition of AMPK and PPARγ partially blocked the regulatory effect of TGDZF, respectively.

CONCLUSIONS

TGDZF alleviated atherosclerosis and promoted cholesterol efflux from macrophages by activating the AMPK-PPARγ-LXRα-ABCA1 pathway.

Targeting the programmed cell death (PCD) signaling mechanism with natural substances for the treatment of diabetic cardiomyopathy (DCM)

Diabetic cardiomyopathy (DCM) is one of the severe complications of diabetes, characterized by structural and functional abnormalities in the hearts of diabetic patients without hypertension, coronary heart disease, or valvular heart disease. DCM can progress to heart failure, which is a significant cause of death in diabetic patients, but currently, there is no effective treatment available. Programmed cell death (PCD) is a genetically regulated form of cell death that includes apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. PCD is essential for tissue homeostasis and normal development of the body. DCM is a complex condition, and abnormalities in the cascade of PCD signaling have been observed in its pathological process, suggesting that targeting PCD could be a potential therapeutic strategy. Studies have shown that natural substances can effectively modulate PCD to intervene in the treatment of DCM, and their use is safe. This review explores the role of different forms of PCD in the pathogenesis of DCM and summarizes the research progress in targeting PCD with natural substances to treat DCM. It can serve as a basis for further research and drug development to provide new treatment strategies for DCM patients.

Tanshinone IIA ameliorates experimental diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress in cardiomyocytes via SIRT1

Diabetic cardiomyopathy (DCM) is a common complication in patients with diabetes, and ultimately leads to heart failure. Endoplasmic reticulum stress (ERS) induced by abnormal glycolipid metabolism is a critical factor that affects the occurrence and development of DCM. Additionally, the upregulation/activation of silent information regulation 2 homolog-1 (SIRT1) has been shown to protect against DCM. Tanshinone II A (Tan IIA), the main active component of Salviae miltiorrhizae radix et rhizome (a valuable Chinese medicine), has protective effects against cardiovascular disease and diabetes. However, its role and mechanisms in diabetes-induced cardiac dysfunction remain unclear. Therefore, we explored whether Tan IIA alleviates ERS-mediated DCM via SIRT1 and elucidated the underlying mechanism. The results suggested that Tan IIA alleviated the pathological changes in the hearts of diabetic mice, ameliorated the cytopathological morphology of cardiomyocytes, reduced the cell death rate, and inhibited the expression of ERS-related proteins and mRNA. The SIRT1 agonist inhibited the activities of glucose-regulated protein 78 (GRP78). Furthermore, the opposite results under the SIRT1 inhibitor. SIRT1 knockdown was induced by siRNA-SIRT1 transfection, and the degree of GRP78 acetylation was increased. Cumulatively, Tan IIA ameliorated DCM by inhibiting ERS and upregulating SIRT1 expression.

Artemisinin attenuates type 2 diabetic cardiomyopathy in rats through modulation of AGE-RAGE/HMGB-1 signaling pathway

Diabetes mellitus is a common metabolic disorder. About two-thirds of diabetic patients develop diabetic cardiomyopathy (DCM), which becomes a challenging issue as it severely threatens the patient's life. Hyperglycemia and the resulting advanced glycated end products (AGE) and their receptor (RAGE)/High Mobility Group Box-1 (HMGB-1) molecular pathway are thought to be key players. Recently, artemisinin (ART) has gained more attention owing to its potent biological activities beyond its antimalarial effect. Herein, we aim to evaluate the effect of ART on DCM and the possible underlying mechanisms. Twenty-four male Sprague-Dawley rats were divided into: control, ART, type 2 diabetic and type 2 diabetic treated with ART groups. At the end of the research, the ECG was recorded, then the heart weight to body weight (HW/BW) ratio, fasting blood glucose, serum insulin and HOMA-IR were evaluated. Cardiac biomarkers (CK-MB and LDH), oxidative stress markers, IL-1β, AGE, RAGE and HMGB-1 expression were also measured. The heart specimens were stained for H&E as well as Masson's trichrome. DCM induced disturbances in all studied parameters; contrary to this, ART improved these insults. Our study concluded that ART could improve DCM through modulation of the AGE-RAGE/HMGB-1 signaling pathway, with subsequent impacts on oxidative stress, inflammation and fibrosis. ART could therefore be a promising therapy for the management of DCM.

Steamed Multigrain Bread Prepared from Dough Fermented with Lactic Acid Bacteria and Its Effect on Type 2 Diabetes

Multigrain products can prevent the occurrence of chronic noninfectious diseases such as hyperglycemia and hyperlipidemia. In this study, multigrain dough fermented by lactic acid bacteria (LAB) was used for the preparation of good-quality steamed multigrain bread, and its effects on type 2 diabetes were investigated. The results showed that the multigrain dough fermented with LAB significantly enhanced the specific volume, texture, and nutritional value of the steamed bread. The steamed multigrain bread had a low glycemic index and was found to increase liver glycogen and reduce triglyceride and insulin levels, while improving oral glucose tolerance and blood lipid levels in diabetic mice. The steamed multigrain bread made from dough fermented with LAB had comparable effects on type 2 diabetes to steamed multigrain bread prepared from dough fermented without LAB. In conclusion, multigrain dough fermentation with LAB improved the quality of the steamed bread while preserving its original efficacy. These findings provide a novel approach to the production of functional commercial foods.

Progress on the role of traditional Chinese medicine in therapeutic angiogenesis of heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiovascular diseases are still the leading cause of death worldwide. Heart failure (HF), as the terminal stage of many cardiovascular diseases, has brought a heavy burden to the global medical system. Microvascular rarefaction (decreased myocardial capillary density) with reduced coronary flow reserve is a hallmark of HF and therapeutic myocardial angiogenesis is now emerging as a promising approach for the prevention and treatment in HF. Traditional Chinese medicine (TCM) has made remarkable achievements in the treatment of many cardiovascular diseases. Growing evidence have shown that their protective effect in HF is closely related to therapeutic angiogenesis.

AIM OF THE STUDY

This review is to enlighten the therapeutic effect and pro-angiogenic mechanism of TCM in HF, and provide valuable hints for the development of pro-angiogenic drugs for the treatment of HF.

MATERIALS AND METHODS

The relevant information about cardioprotective TCM was collected from electronic scientific databases such as PubMed, Web of Science, ScienceDirect, and China National Knowledge Infrastructure (CNKI).

RESULTS

The studies showed that TCM formulas, extracts, and compounds from herbal medicines can provide therapeutic effect in HF with their pro-angiogenic activity. Their actions are achieved mainly by regulating the key angiogenesis factors particularly VEGF, as well as related regulators including signal molecules and pathways, non-coding miRNAs and stem cells.

CONCLUSION

TCM and their active components might be promising in therapeutic angiogenesis for the treatment of HF.

Development of alkaline phosphatase-scFv and its use for one-step enzyme-linked immunosorbent assay for His-tagged protein detection

A histidine (His)-tag is composed of six His residues and typically exerts little influence on the structure and solubility of expressed recombinant fusion proteins. Purification methods for recombinant proteins containing His-tags are relatively well-established, thus His-tags are widely used in protein recombination technology. We established a one-step enzyme-linked immunosorbent assay (ELISA) for His-tagged recombinant proteins. We analyzed variable heavy and light chains of the anti-His-tag monoclonal antibody 4C9 and used BLAST analyses to determine variable zones in light (VL) and heavy chains (VH). VH, VL, and alkaline phosphatase (ALP) regions were connected via a linker sequence and ligated into the pGEX-4T-1 expression vector. Different recombinant proteins with His tags were used to evaluate and detect ALP-scFv activity. Antigen and anti-His-scFv-ALP concentrations for direct ELISA were optimized using the checkerboard method. ZIKV-NS1, CHIKV-E2, SCRV-N, and other His-tag fusion proteins demonstrated specific reactions with anti-His-scFv-ALP, which were accurate and reproducible when the antigen concentration was 50 µg mL−1 and the antibody concentration was 6.25 µg mL−1. For competitive ELISA, we observed a good linear relationship when coating concentrations of recombinant human anti-Müllerian hormone (hAMH) were between 0.78 and 12.5 µg mL−1. Our direct ELISA method is simple, rapid, and accurate. The scFv antibody can be purified using a prokaryotic expression system, which provides uniform product quality and reduces variations between batches.

Syringic Acid Ameliorates Cardiac, Hepatic, Renal and Neuronal Damage Induced by Chronic Hyperglycaemia in Wistar Rats: A Behavioural, Biochemical and Histological Analysis

This study investigated the effects of syringic acid (SA) on renal, cardiac, hepatic, and neuronal diabetic complications in streptozotocin-induced neonatal (nSTZ) diabetic rats. STZ (110 mg/kg i.p) was injected into Wistar rat neonates as a split dose (second and third postnatal day). Diabetes mellitus was diagnosed in adults by measuring fasting blood glucose levels, urine volume, and food and water intake. The treatment of SA (25 mg/kg, 50 mg/kg p.o) was given from the 8th to 18th postnatal week. To assess the development of diabetic complications and the effect of therapy, biochemical indicators in serum and behavioural parameters were recorded at specific intervals during the study period. SA (25 mg/kg, 50 mg/kg p.o) treatment reduced hyperglycaemia, polydipsia, polyphagia, polyuria, relative organ weight, cardiac hypertrophic indices, inflammatory markers, cell injury markers, glycated haemoglobin, histopathological score, and oxidative stress, and increased Na/K ATPase activity. These findings suggest that SA might significantly alleviate diabetic complications and/or renal, neuronal, cardiac, and hepatic damage in nSTZ diabetic rats.

Effect of different doses of colchicine on high sensitivity C-reactive protein in patients with acute minor stroke or transient ischemic attack: A pilot randomized controlled trial

BACKGROUND AND PURPOSE

Patients with elevated levels of high-sensitivity C-reactive protein (hsCRP) are at increased risk of recurrent stroke. Colchicine is a unique anti-inflammatory medication that has shown promise in reducing cardiovascular event. The current study mainly tested the ability of colchicine at different doses to reduce hsCRP levels after stroke.

METHODS

This was a randomized controlled and open label trial. Eligible patients with acute minor ischemic stroke or transient ischemic attack (TIA) were randomized within 24 hours after symptom onset in a 1:1:1:1 ratio to four groups with different doses of colchicine. Group 1: 0.5 mg of colchicine per day for 14 days; groups 2: starting with 1mg of colchicine on days 1 through 7, and maintaining with 0.5 mg per day on days 8 through 14; group 3 and 4: respectively 2 mg and 3 mg of colchicine on day 1, following with 1mg per day on days 2 through 7 and continuing with 0.5 mg per day on days 8 through 14. Blood specimens were collected at randomization, 24 hours, 72 hours, 7 days and 14 days after index event for hsCRP measurements. The primary outcome was the change of hsCRP levels between baseline and 14 days.

RESULTS

A total of 39 patients were enrolled. Patients in group 2 had reduced level of hsCRP at 14-day compared with baseline value (p=0.005). Time-course analyses showed that patients in groups of 1 and 2 had lower hsCRP level at 7-day than that at baseline, and patients in groups of 1, 2 and 3 had lower ratios of hsCRP levels at 72 hours to those at baseline. Low dose of colchicine was well tolerated without discontinuation of drug.

CONCLUSION

Early treatment with low dose of colchicine reduced hsCRP levels in the patients with acute minor ischemic stroke and TIA.

Combination of Salviae Miltiorrhizae Radix et Rhizoma and Carthami Flos improves cardiac function of diabetic cardiomyopathy mice by regulating the unfolded protein response signaling pathway

Diabetic cardiomyopathy (DCM) is a unique clinical entity elicited by diabetes independent of other cardiovascular risk factors, of which the pathological mechanisms and treatment strategies remain largely undefined. This study aimed to clarify the role of unfolded protein response (UPR) signaling pathway in the pathogenesis of DCM, and to explore the effect of aqueous extract of Salviae Miltiorrhizae Radix et Rhizoma and Carthami Flos (DH) on DCM mice. Cardiac function of DCM mice was evaluated by echocardiography, and lipid profile of left ventricular was analyzed by untargeted lipidomics. The results showed that DH significantly improved the diabetic symptoms, cardiac dyslipidemia, and systolic dysfunction of DCM mice. UPR signaling pathway was significantly down-regulated in the left ventricular of DCM mice. DH significantly up-regulated the transcriptions of key transducers in UPR signaling pathway. Conditional knockout of Xbp1 in cardiomyocyte (a key regulator in UPR signaling pathway) eliminated the protective effect of DH on cardiac systolic function of DCM mice, which suggested that UPR signaling pathway, especially the Xbp1, was required for DH protection against DCM. In conclusion, DH improved cardiac function of DCM mice, and this effect was dependent on its regulation of UPR signaling pathway.

Lactiplantibacillus plantarum Y15 alleviate type 2 diabetes in mice via modulating gut microbiota and regulating NF-κB and insulin signaling pathway

Probiotics have been used for the treatment of chronic metabolic diseases, including type 2 diabetes (T2D). However, the mechanisms of antidiabetic effects are not well understood. The object of this study is to assess the antidiabetic effect of Lactiplantibacillus plantarum Y15 isolated from Chinese traditional dairy products in vivo. Results revealed that L. plantarum Y15 administration improved the biochemical indexes related to diabetes, reduced pro-inflammatory cytokines, L. plantarum Y15 administration reshaped the structure of gut microbiota, decreased the abundance of LPS-producing, and increased short-chain fatty acids (SCFAs)-producing bacteria, which subsequently reduce the levels of lipopolysaccharide (LPS) and pro-inflammatory cytokines. L. plantarum Y15 administration also regulated the expressions of the inflammation and insulin signaling pathway-related genes. These results suggest that L. plantarum Y15 may serve as a potential probiotic for developing food products to ameliorate T2D.

Glycemic Control and the Heart: The Tale of Diabetic Cardiomyopathy Continues

Cardiovascular diseases are the leading cause of death in people with diabetes. Diabetic cardiomyopathy (DC) is an important complication of diabetes and represents a distinct subtype of heart failure that occurs in absence of cardiovascular diseases. Chronic hyperglycemia and hyperinsulinemia along with insulin resistance and inflammatory milieu are the main mechanisms involved in the pathophysiology of DC. Changes in lifestyle favoring healthy dietary patterns and physical activity, combined with more innovative anti-diabetes therapies, are the current treatment strategies to safeguard the cardiovascular system. This review aims at providing an updated comprehensive overview of clinical, pathogenetic, and molecular aspects of DC, with a focus on the effects of anti-hyperglycemic drugs on the prevention of pump dysfunction and consequently on cardiovascular health in type 2 diabetes.

Combination Therapy with GABA and MgSO4 Improves Insulin Sensitivity in Type 2 Diabetic Rat

BACKGROUND

Gamma-aminobutyric acid (GABA) and magnesium sulfate (MgSO₄) play a crucial role in glycemic control. Therefore, we studied the effect of combination therapy with GABA and MgSO₄ to improve insulin sensitivity in diabetes induced by streptozotocin as well as high-fat diet in a diabetic rat model. Design and Methods. Forty randomly selected rats were assigned to four groups: nondiabetic control group was fed the normal diet, insulin-resistant diabetic rat model was induced by streptozotocin and high-fat diet, GABA + MgSO₄ group received GABA and MgSO₄, and insulin group was treated with insulin. Body weight, abdominal fat, blood glucose, serum insulin, and glucagon concentration were measured. The glucose clamp technique, glucose tolerance test, and insulin tolerance test were performed to study insulin sensitivity. Also, the expressions of glucose 6 phosphatase, glucagon receptor, and phosphoenolpyruvate carboxykinase genes in liver were assessed for the gluconeogenesis pathway. Protein translocation and glucose transporter 4 (Glut4) genes expression in muscle were also assessed.

RESULTS

Combination of GABA + MgSO₄ or insulin therapy enhanced insulin level, glycemic control, glucose and insulin tolerance test, some enzymes expression in the gluconeogenesis pathway, body fat, body weight, and glucagon receptor in diabetic rats. Moreover, an increase was observed in protein and gene expression of Glut4. Insulin sensitivity in combination therapy was more than the insulin group.

CONCLUSIONS

GABA and MgSO₄ enhanced insulin sensitivity via increasing Glut4 and reducing the gluconeogenesis enzyme and glucagon receptor gene expressions.

WITHDRAWN: Effect of 2-dodecyl-6-methoxycyclohexa-2, 5-diene-1, 4-dione, isolated from Averrhoa carambola L. (Oxalidaceae) roots, on advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice

The Publisher regrets that this article is an accidental duplication of an article that has already been published in [Toxicology Letters, 339C (2021) 88–96], https://doi.org/10.1016/j.toxlet.2020.11.022. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

The effect of 4-week endurance training on serum levels of irisin and betatrophin in streptozotocin- induced diabetic rats

Betatrophin known as pancreatic β-cell proliferation marker is secreted as a result of the muscle irisin's expression induced by exercise. The present study aimed to investigate the effect of endurance training on serum levels of irisin and betatrophin in diabetic rats. Twenty-four Wistar rats were randomly divided into three groups of (1) healthy control group (H-CG), (2) diabetic control group (D-CG), and diabetic group submitted to endurance training (D-ETG). The D-ETG performed endurance exercise (4 week/5 days) on the rodent treadmill. For data analysis we used one-way ANOVA, Scheffe test and Pearson correlation coefficient. Irisin (p = .04) and betatrophin (p = .005) levels were significantly decreased in the D-CG. Endurance exercise only increased serum levels of irisin significantly (p = .03). There was a significant correlation was shown between serum betatrophin and beta-cell function (p = .03). It appears that a specific exercise training can increase irisin hormone, with possible impact on betatrophin expression in diabetic individuals.

Diabetic Cardiomyopathy: From Mechanism to Management in a Nutshell

Diabetic cardiomyopathy (DCM) is a significant complication of diabetes mellitus characterized by gradually failing heart with detrimental cardiac remodelings, such as fibrosis and diastolic and systolic dysfunction, which is not directly attributable to coronary artery disease. Insulin resistance and resulting hyperglycemia is the main trigger involved in the initiation of diabetic cardiomyopathy. There is a constellation of many pathophysiological events, such as lipotoxicity, oxidative stress, inflammation, inappropriate activation of the renin-angiotensin-aldosterone system, dysfunctional immune modulation promoting increased rate of cardiac cell injury, apoptosis, and necrosis, which ultimately culminates into interstitial fibrosis, cardiac stiffness, diastolic dysfunction, initially, and later systolic dysfunction too. These events finally lead to clinical heart failure of DCM. Herein, The pathophysiology of DCM is briefly discussed. Furthermore, potential therapeutic strategies currently used for DCM are also briefly mentioned.

Screening for Potential Novel Probiotics With Dipeptidyl Peptidase IV-Inhibiting Activity for Type 2 Diabetes Attenuation in vitro and in vivo

Diabetes has become the second most severe disease to human health. Probiotics are important for maintaining gastrointestinal homeostasis and energy balance and have been demonstrated to play a positive role in the prevention and treatment of metabolic syndromes, such as obesity, inflammation, dyslipidemia, and hyperglycemia. The objective of this study was to screen potential antidiabetic strains in vitro and evaluate its effects in vivo. For the in vitro section, dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant activities of 14 candidate Lactobacillus spp. strains were tested. Then hydrophobicity and acid and bile salt tolerance assays were determined. The most promising in vitro strain was further evaluated for its antidiabetic properties in vivo using type 2 diabetes mice induced by high-fat diet and intraperitoneal injection of streptozotocin (STZ). The reference strain for this study was Lactobacillus rhamnosus GG. Results showed that cell-free excretory supernatants and cell-free extracts of Lactobacillus acidophilus KLDS1.0901 had better DPP-IV inhibitory activity, antioxidative activities, and biological characteristics than other strains. At the end of the treatment, we found that L. acidophilus KLDS1.0901 administration decreased the levels of fasting blood glucose (FBG), glycosylated hemoglobin, insulin in serum and AUC_glucose, and increased the level of glucagon-like peptide 1 in serum compared with diabetic mice (p < 0.05). Moreover, L. acidophilus KLDS1.0901 supplementation increased the activities of superoxide dismutase, glutathione peroxidase, the level of glutathione, and reduced the level of malondialdehyde in serum. These results indicated that L. acidophilus KLDS1.0901 could be used as a potential antidiabetic strain; its application as food supplement and drug ingredient is thus recommended.

Early Treatment With Metformin in a Mice Model of Complex Regional Pain Syndrome Reduces Pain and Edema

BACKGROUND

Metformin, an adenosine monophosphate (AMP)-activated protein kinase activator, as well as a common drug for type 2 diabetes, has previously been shown to decrease mechanical allodynia in mice with neuropathic pain. The objective of this study is to determine if treatment with metformin during the first 3 weeks after fracture would produce a long-term decrease in mechanical allodynia and improve a complex behavioral task (burrowing) in a mouse tibia fracture model with signs of complex regional pain syndrome.

METHODS

Mice were allocated into distal tibia fracture or nonfracture groups (n = 12 per group). The fracture was stabilized with intramedullary pinning and external casting for 21 days. Animals were then randomized into 4 groups (n = 6 per group): (1) fracture, metformin treated, (2) fracture, saline treated, (3) nonfracture, metformin treated, and (4) nonfracture, saline treated. Mice received daily intraperitoneal injections of metformin 200 mg/kg or saline between days 14 and 21. After cast removal, von Frey force withdrawal (every 3 days) and burrowing (every 7 days) were tested between 25 and 56 days. Paw width was measured for 14 days after cast removal. AMP-activated protein kinase downregulation at 4 weeks after tibia fracture in the dorsal root ganglia was examined by immunohistochemistry for changes in the AMP-activated protein kinase pathway.

RESULTS

Metformin injections elevated von Frey thresholds (reduced mechanical allodynia) in complex regional pain syndrome mice versus saline-treated fracture mice between days 25 and 56 (difference of mean area under the curve, 42.5 g·d; 95% CI of the difference, 21.0-63.9; P < .001). Metformin also reversed burrowing deficits compared to saline-treated tibial fracture mice (difference of mean area under the curve, 546 g·d; 95% CI of the difference, 68-1024; P < .022). Paw width (edema) was reduced in metformin-treated fracture mice. After tibia fracture, AMP-activated protein kinase was downregulated in dorsal root ganglia neurons, and mechanistic target of rapamycin, ribosomal S6 protein, and eukaryotic initiation factor 2α were upregulated.

CONCLUSIONS

The important finding of this study was that early treatment with metformin reduces mechanical allodynia in a complex regional pain syndrome model in mice. Our findings suggest that AMP-activated protein kinase activators may be a viable therapeutic target for the treatment of pain associated with complex regional pain syndrome.

Metformin in combination with rosiglitazone contribute to the increased serum adiponectin levels in people with type 2 diabetes mellitus

To evaluate how metformin plus rosiglitazone affect serum adiponectin levels in people suffering from type 2 diabetes mellitus (T2DM), 240 patients having T2DM were selected in this cohort study. Included subjects were randomly and equally separated into three subsets: i) Group A (rosiglitazone group); ii) group B (metformin group); and iii) group C (rosiglitazone + metformin group). Furthermore, meta-analysis of previous studies was performed by searching the general search engines and bibliographic databases. Compared with before treatment, the serum amount of adiponectin grew considerably in the three groups after treatment, and the levels in the group C was much greater than those of groups A and B (all P<0.05). Corresponding meta-analysis results suggested post-treatment serum adiponectin level to be greater than pretreatment level in T2DM patients (P<0.001). Further subgroup analyses indicated that combination therapy of metformin and rosiglitazone may increase the amount of serum adiponectin in T2DM sufferers among the majority subgroups (all P<0.05). The combination of metformin and rosiglitazone treatment increased serum adiponectin levels, suggesting that metformin plus rosiglitazone therapy is a suitable choice to treat T2DM.

Diabetic cardiomyopathy: where we are and where we are going

The global burden of diabetes mellitus and its related complications are currently increasing. Diabetes mellitus affects the heart through various mechanisms including microvascular impairment, metabolic disturbance, subcellular component abnormalities, cardiac autonomic dysfunction, and a maladaptive immune response. Eventually, diabetes mellitus can cause functional and structural changes in the myocardium without coronary artery disease, a disorder known as diabetic cardiomyopathy (DCM). There are many diagnostic tools and management options for DCM, although it is difficult to detect its development and effectively prevent its progression. In this review, we summarize the current research regarding the pathophysiology and pathogenesis of DCM. Moreover, we discuss emerging diagnostic evaluation methods and treatment strategies for DCM, which may help our understanding of its underlying mechanisms and facilitate the identification of possible new therapeutic targets.

Effects of Lactobacillus plantarum CCFM0236 on hyperglycaemia and insulin resistance in high-fat and streptozotocin-induced type 2 diabetic mice

AIMS

The aim of this study was to rapidly screen potential hypoglycaemic strain by α-glucosidase inhibitory activity in vitro, then explored the antidiabetic effect of Lactobacillus plantarum CCFM0236 in vivo.

METHODS AND RESULTS

The cell-free supernatant of Lact. plantarum CCFM0236 significantly inhibited α-glucosidase activity in vitro. Therefore, the effects of Lact. plantarum CCFM0236, with potential hypoglycaemia activity, on insulin resistance and hyperglycaemia were explored in high-fat and streptozotocin-induced type 2 diabetes mice. Oral administration of Lact. plantarum CCFM0236 was found to decrease food intake, blood glucose level, glycosylated haemoglobin level and leptin level. Treatments of Lact. plantarum CCFM0236 also favourably regulated insulin level, AUC_glucose , and HOMA-IR index, and increased the activities of glutathione peroxidase and the levels of glutathione, high-density lipoprotein cholesterol and interleukin-10. In addition, Lact. plantarum CCFM0236 reduced levels of malondialdehyde and tumour necrosis factor-α and protected pancreas function.

CONCLUSIONS

Lactobacillus plantarum CCFM0236 has potential hypoglycaemic ability by ameliorating insulin resistance, antioxidant capacity and systemic inflammation in mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

The method of α-glucosidase inhibitory activity could be effectively used to screen potential hypoglycaemic products and Lact. plantarum CCFM0236 might be a promising therapeutic agent for ameliorating type 2 diabetes.

Protective Effects of MDG-1, a Polysaccharide from Ophiopogon japonicus on Diabetic Nephropathy in Diabetic KKAy Mice

Ophiopogon japonicus is a traditional Chinese medicine that might be effective for treating type 2 diabetes. Recent research confirmed that MDG-1, a polysaccharide from O. japonicas, activates the PI3K/Akt signaling pathway and improves insulin sensitivity in a diabetic KKA^y mouse model, but little is known about its effects on diabetic nephropathy. In this study, KKA^y mice were orally administered distilled water (control group), MDG-1, or rosiglitazone for 12 weeks. Blood glucose levels were tested every two weeks for the fed mice. At 6 and 12 weeks, blood samples were collected for biochemical examination. At the end of the experiment, all kidney tissues were collected for histological examination and western blot analysis. Results show that MDG-1 (300 mg/kg) significantly decreased the levels of blood glucose, triglycerides, blood urine nitrogen and albumin, and significantly inhibited the expression of transforming growth factor-beta 1 and connective tissue growth factor. Moreover, MDG-1 could alleviate glomerular mesangial expansion and tubulointerstitial fibrosis in the diabetic mice, as confirmed by histopathological examination. These data indicated that MDG-1 ameliorates renal disease in diabetic mice by reducing hyperglycemia, hyperinsulinemia, and hyperlipidemia, and by inhibiting intracellular signaling pathways.

Levosimendan suppresses oxidative injury, apoptotic signaling and mitochondrial degeneration in streptozotocin-induced diabetic cardiomyopathy

Diabetic cardiomyopathy plays a major role in morbidity and mortality among cardiovascular disorder-related complications. This study was designed to explore long-term benefits of Levosimendan (LEVO) along with Ramipril and Insulin. Diabetic cardiomyopathy was induced using streptozotocin (STZ) at the dose of 25 mg/kg/body weight/day for three consecutive days in Wistar rats. Rats were randomly divided into 10 groups and treatments were started after 2 weeks of STZ administration. A gradual but severe hyperglycemia ((§§§)p < 0.001) was observed in all STZ-treated groups except those received insulin (2  U/day). LEVO alone and in combination with Ramipril and Insulin normalized (**p < 0.01) mean arterial pressure and heart rate, restored catalase, superoxide dismutase, malondialdehyde, glutathione level and also attenuated (***p < 0.001) the raised serum levels of creatine kinase-heart type, lactate dehydrogenase, tumor necrosis factor-alpha, C-reactive protein, and caspase-3 level in heart tissue altered after STZ treatment. Myofibril degeneration, mitochondrial fibrosis and vacuolization occurred after STZ treatment, were also reversed by LEVO in combination with Ramipril and Insulin. The combination of LEVO with Ramipril and Insulin improved hemodynamic functions, maintained cardiac enzymes and ameliorated myofibril damage in diabetic cardiomyopathy.

Effect of endurance training on retinol-binding protein 4 gene expression and its protein level in adipose tissue and the liver in diabetic rats induced by a high-fat diet and streptozotocin

AIMS/INTRODUCTION

The present study was designed to investigate from which tissues the decrease in retinol-binding protein 4 (RBP4) expression could contribute to the improvement of serum RBP4 and insulin resistance (IR) after endurance training.

MATERIALS AND METHODS

Male 7-week-old Wistar rats were randomly assigned into four groups including control (C), trained (T), diabetic control (DC) and trained diabetic (TD). At 8 weeks-of-age, diabetes was induced by a high-fat diet and intraperitoneal injection of low-dose streptozotocin (STZ; 35 mg/kg). Rats in the T and TD groups carried out a 7-week exercise program on a motorized treadmill (15-20 m/min for 20 min/day for 5 weeks), whereas the C and DC remained sedentary in their cages. Tissues gene expression and protein levels of RBP4 were assessed by using real-time polymerase chain reaction and western blot, respectively, while serum RBP4 was measured using an enzyme-linked immunosorbent assay kit.

RESULTS

Exercise significantly improved IR and reduced serum concentration of RBP4 in the TD group. This reduction of serum RBP4 was accompanied by decreased RBP4 protein expression in visceral fat tissue. In contrast, exercise had no significant effect on RBP4 expression in liver and subcutaneous fat tissue in the TD group. Exercise also significantly decreased RBP4 gene expression in visceral fat tissue and muscle, whereas the effect of exercise on liver RBP4 messenger ribonucleic acid expression was not significant.

CONCLUSIONS

The present study showed that the mechanism for RBP4 reducing the effect of endurance training could involve decreased RBP4 messenger ribonucleic acid expression and its protein level in adipose tissue in STZ-induced diabetic rats.

Diabetic cardiomyopathy: Pathophysiology, diagnostic evaluation and management

Diabetes affects every organ in the body and cardiovascular disease accounts for two-thirds of the mortality in the diabetic population. Diabetes-related heart disease occurs in the form of coronary artery disease (CAD), cardiac autonomic neuropathy or diabetic cardiomyopathy (DbCM). The prevalence of cardiac failure is high in the diabetic population and DbCM is a common but underestimated cause of heart failure in diabetes. The pathogenesis of diabetic cardiomyopathy is yet to be clearly defined. Hyperglycemia, dyslipidemia and inflammation are thought to play key roles in the generation of reactive oxygen or nitrogen species which are in turn implicated. The myocardial interstitium undergoes alterations resulting in abnormal contractile function noted in DbCM. In the early stages of the disease diastolic dysfunction is the only abnormality, but systolic dysfunction supervenes in the later stages with impaired left ventricular ejection fraction. Transmitral Doppler echocardiography is usually used to assess diastolic dysfunction, but tissue Doppler Imaging and Cardiac Magnetic Resonance Imaging are being increasingly used recently for early detection of DbCM. The management of DbCM involves improvement in lifestyle, control of glucose and lipid abnormalities, and treatment of hypertension and CAD, if present. The role of vasoactive drugs and antioxidants is being explored. This review discusses the pathophysiology, diagnostic evaluation and management options of DbCM.

Effect of 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from Averrhoa carambola L. (Oxalidaceae) roots, on advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice

The roots of Averrhoa carambola L. (Oxalidaceae) have a long history of medical use in traditional Chinese medicine for treating diabetes and diabetic nephropathy. 2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) was isolated from the tuberous roots of A. carambola L. The purpose of this study was to investigate the beneficial effect of DMDD on the advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice with regard to prove its efficacy by local traditional practitioners in the treatment of kidney frailties in diabetics. KKAy mice were orally administrated DMDD (12.5, 25, 50mg/kg body weight/d) or aminoguanidine (200mg/kg body weight/d) for 8 weeks. Hyperglycemia, renal AGE formation, and the expression of related proteins, such as the AGE receptor, nuclear factor-κB, transforming growth factor-β1, and N(ε)-(carboxymethyl)lysine, were markedly decreased by DMDD. Diabetes-dependent alterations in proteinuria, serum creatinine, creatinine clearance, and serum urea-N and glomerular mesangial matrix expansion were attenuated after treatment with DMDD for 8 weeks. The activities of superoxide dismutase and glutathione peroxidase, which are reduced in the kidneys of KKAy mice, were enhanced by DMDD. These findings suggest that DMDD may inhibit the progression of diabetic nephropathy and may be a therapeutic agent for regulating several pharmacological targets to treat or prevent of diabetic nephropathy.

Dual therapy of rosiglitazone/pioglitazone with glimepiride on diabetic nephropathy in experimentally induced type 2 diabetes rats

Diabetic nephropathy is a major cause of end-stage renal disease (ESRD) in the general population. It is estimated that diabetic nephropathy will eventually develop in about 40% of all patients with diabetes; therefore, prevention is critical for delaying the development and progression of diabetic kidney disease. Despite extensive efforts, medical advances are still not successful enough to prevent the progression of the disease. In the present study, we focused on the comparison of combination therapies and whether they offered additional renoprotection. Type 2 diabetes mellitus was induced by intraperitoneally administering streptozotocin (90 mg/kg) in neonatal rats and then these rats were treated with rosiglitazone (1.0 mg/kg) in combination with glimepiride (0.5 mg/kg) or with pioglitazone (2.5 mg/kg) in combination with glimepiride (0.5 mg/kg). Diabetic nephropathy markers were evaluated by biochemical and ELISA kits and renal structural changes were examined by light microscopy and transmission electron microscopy. Results show that the combination of pioglitazone with glimepiride is more effective in amelioration of diabetic nephropathy than rosiglitazone with glimepiride drug therapy due to glycemic control, suppressing albumin excretion rate, total protein excretion rate and augmented TNF-a signaling during the development of streptozotocin induced type 2 diabetic nephropathy.

Effect of crocin on the insulin resistance and lipid profile of streptozotocin-induced diabetic rats

Crocin is the only water soluble carotenoid in nature, and it has a known powerful antioxidant activity. The aim of this work was to investigate the hypoglycemic and hypolipidemic effects of crocin in streptozotocin (STZ)-induced type 2 diabetic rats. Neonatal male Wistar rats (2-5 days old) were randomly divided into five groups. Three groups were intraperitoneally injected with STZ (90 mg/kg body weight). Among them, two groups were treated with intraperitoneal injection of crocin (50 or 100 mg/kg), and the third group was treated with vehicle only. Two control groups were also considered, and one of them was treated with crocin. After 5 months, their blood and urine samples were collected, and the animals were sacrified. The results indicate a significant lower body weight (P < 0.001) and abnormal parameters in the diabetic rats compared with the normal group. An administration of both doses of crocin significantly decreased the levels of serum glucose, advanced glycation end products, triglyceride, total cholesterol, and low-density lipoprotein and increased the high-density lipoprotein in the diabetic rats. The treatments were also effective in decreasing HbA1c and microalbuminuria, as well as homeostatic model assessment for insulin resistance as a measure of insulin resistance in the diabetic rats.

Sitagliptin, sitagliptin and metformin, or sitagliptin and amitriptyline attenuate streptozotocin-nicotinamide induced diabetic neuropathy in rats

Diabetic neuropathies are a family of nerve disorders caused by diabetes. Symptoms of the disease include nerve palsy, mononeuropathy, mononeuropathy multiplex, diabetic amyotrophy, painful polyneuropathy, autonomic neuropathy, and thoracoabdominal neuropathy. In this study, type 2 diabetes in rats was induced with nicotinamide-streptozotocin. Drug treatment was initiated on the d 15, with the combination regimen of metformin, pioglitazone and glimipiride or metformin and sitagliptin or sitagliptin, amitriptyline and sitagliptin and led to significantly improved glycemic control, increased grip strength and paw jumping response on d 21, 28 and 35 (P < 0.001). Significant increases in blood protein levels and decreases in urinary protein levels were observed in the animals treated with the different regimens on d 21, 28 and 35 (P < 0.001). Combined treatment of streptozotocin and nicotinamide caused marked degeneration of nerve cells, while administration of metformin and sitagliptin showed tissue regeneration and no body weight gain. In conclusion, treatment with sitagliptin and sitagliptin combined with metformin or amitriptyline results in no body weight gain, but causes an increase in grip strength and pain sensitivity, exhibits neural protection, and reverses the alteration of biochemical parameters in rats with streptozotocin-nicotinamide induced type 2 diabetes.

Fagopyrum tataricum (buckwheat) improved high-glucose-induced insulin resistance in mouse hepatocytes and diabetes in fructose-rich diet-induced mice

Fagopyrum tataricum (buckwheat) is used for the treatment of type 2 diabetes mellitus in Taiwan. This study was to evaluate the antihyperglycemic and anti-insulin resistance effects of 75% ethanol extracts of buckwheat (EEB) in FL83B hepatocytes by high-glucose (33 mM) induction and in C57BL/6 mice by fructose-rich diet (FRD; 60%) induction. The active compounds of EEB (100 μg/mL; 50 mg/kg bw), quercetin (6 μg/mL; 3 mg/kg bw), and rutin (23 μg/mL; 11.5 mg/kg bw) were also employed to treat FL83B hepatocytes and animal. Results indicated that EEB, rutin, and quercetin + rutin significantly improved 2-NBDG uptake via promoting Akt phosphorylation and preventing PPARγ degradation caused by high-glucose induction for 48 h in FL83B hepatocytes. We also found that EEB could elevate hepatic antioxidant enzymes activities to attenuate insulin resistance as well as its antioxidation caused by rutin and quercetin. Finally, EEB also inhibited increases in blood glucose and insulin levels of C57BL/6 mice induced by FRD.

The protective effect of Salvia miltiorrhiza in an animal model of early experimentally induced diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is the most common cause of end stage renal disease. In this study, the effects of Salvia miltiorrhiza (SM) were studied in an experimental rat model of DN that was induced by streptozotocin (STZ) treatment.

MATERIALS AND METHODS

Diabetes was induced in male Sprague-Dawley rats (290 ± 10 g) by injecting STZ (45 mg/kg) into the tail vein. After development of diabetes, the rats were treated with SM (500 mg/kg) for 8 weeks in order to analyze its renoprotective effect, which was evaluated by means of blood glucose level, urine protein, and the expression of advanced glycation end-products (AGEs), receptor of advanced glycation end-products (RAGE), transforming growth factor β1 (TGF-β1), collagen IV, and monocyte/macrophage (ED-1) infiltration.

RESULTS

High levels of 24-h urinary protein excretion were ameliorated by SM. Moreover, the serum and kidney levels of transforming growth factor β1 (TGF-β1) and the kidney levels of collagen IV, monocytes/macrophages (ED-1) and the receptor for advanced glycation end-products (RAGE), were significantly reduced.

CONCLUSIONS

These findings suggest that SM might inhibit the progression of DN and could be a therapeutic agent for regulating several pharmacological targets for treatment or prevention of DN.

Cardioprotective activity of alcoholic extract of Tinospora cordifolia (Willd.) Miers in calcium chloride-induced cardiac arrhythmia in rats

The present study investigated the antiarrhythmic activity of alcoholic extract of Tinospora cordifolia (T. cordifolia) in CaCl2 induced arrhythmia. CaCl2 (25 mg/kg) was administered by intravenous infusion (iv) to produce arrhythmia in rats. The animals were then treated with T. cordifolia extract (150, 250, and 450 mg/kg) and verapamil (5 mg/kg,iv). Lead II electrocardiogram was monitored. Plasma calcium, sodium and potassium levels were measured. In CaCl2 induced arrhythmia, heart rate was decreased by 41.10%, T. cordifolia at 150, 300, and 450 mg/kg decreased the heart rate by 26.30%, 29.16%, and 38.29%, respectively, and verapamil reduced the heart rate by 9.70% compared to the normal group. The PQRST waves were normalized and atrial and ventricular fibrillation was controlled in rats treated with verapamil and T. cordifolia. CaCl2 increased calcium and sodium levels and decreased potassium levels in blood. T. cordifolia dose-dependently decreased calcium and sodium levels and increased potassium levels. Hence, T. cordifolia can be used in antiarrhythmic clinical settings and beneficial in atrial and ventricular fibrillation and flutter and may be indicated in ventricular tachyarrhythmia.

Dual therapy versus monotherapy of trandolapril and telmisartan on diabetic nephropathy in experimentally induced type 2 diabetes mellitus rats

Objective: To investigate the combination of telmisartan with trandolapril therapy versus monotherapy of trandolapril and telmisartan on diabetic nephropathy in type 2 diabetes mellitus rats.

Material and methods: Neonatal rats (2 days old) were used for inducing type 2 diabetes mellitus. Streptozotocin at a dose of 90 mg/kg, in freshly prepared citrate buffer (0.1M, pH 4.5), was injected intraperitoneally. There were five groups: (1) normal control, (2) diabetic control, (3) diabetic treated with telmisartan, (4) diabetic treated with trandolapril and (5) diabetic treated with telmisartan and trandolapril. Albumin excretion rate, total protein excretion rate, plasma fibronectin, transforming growth factor beta 1(TGF-β1), tumour necrosis factor-α (TNF-α) concentration and renal structural changes were measured.

Results: Albumin excretion rate, total protein excretion rate, plasma fibronectin, TGF-β1, TNF-α concentration and renal structural changes increased significantly in untreated diabetic rats compared with normal control rats. Administration of telmisartan, trandolapril, or both decreased these changes.

Conclusions: Addition of the telmisartan to trandolapril was more effective in reducing renal structural changes and improvement of renal function than monotherapy with either drug, possibly due to dual inhibitory effect on the renin— angiotensin system, and thus suppression of TGF-β1, TNF-α.

Comparison of antioxidant effects of honey, glibenclamide, metformin, and their combinations in the kidneys of streptozotocin-induced diabetic rats

Hyperglycemia-induced increase in oxidative stress is implicated in diabetic complications. This study investigated the effect of metformin and/or glibenclamide in combination with honey on antioxidant enzymes and oxidative stress markers in the kidneys of streptozotocin (60 mg/kg; intraperitoneal)-induced diabetic rats. Diabetic rats were randomized into eight groups of five to seven rats and received distilled water (0.5 mL); honey (1.0 g/kg); metformin (100 mg/kg); metformin (100 mg/kg) and honey (1.0 g/kg); glibenclamide (0.6 mg/kg); glibenclamide (0.6 mg/kg) and honey (1.0 g/kg); metformin (100 mg/kg) and glibenclamide (0.6 mg/kg); or metformin (100 mg/kg), glibenclamide (0.6 mg/kg) and honey (1.0 g/kg) orally once daily for four weeks. Malondialdehyde (MDA) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were significantly elevated while catalase (CAT) activity, total antioxidant status (TAS), reduced glutathione (GSH), and GSH:oxidized glutathione (GSSG) ratio was significantly reduced in the diabetic kidneys. CAT, glutathione reductase (GR), TAS, and GSH remained significantly reduced in the diabetic rats treated with metformin and/or glibenclamide. In contrast, metformin or glibenclamide combined with honey significantly increased CAT, GR, TAS, and GSH. These results suggest that combination of honey with metformin or glibenclamide might offer additional antioxidant effect to these drugs. This might reduce oxidative stress-mediated damage in diabetic kidneys.

Rodent models for metabolic syndrome research

Rodents are widely used to mimic human diseases to improve understanding of the causes and progression of disease symptoms and to test potential therapeutic interventions. Chronic diseases such as obesity, diabetes and hypertension, together known as the metabolic syndrome, are causing increasing morbidity and mortality. To control these diseases, research in rodent models that closely mimic the changes in humans is essential. This review will examine the adequacy of the many rodent models of metabolic syndrome to mimic the causes and progression of the disease in humans. The primary criterion will be whether a rodent model initiates all of the signs, especially obesity, diabetes, hypertension and dysfunction of the heart, blood vessels, liver and kidney, primarily by diet since these are the diet-induced signs in humans with metabolic syndrome. We conclude that the model that comes closest to fulfilling this criterion is the high carbohydrate, high fat-fed male rodent.

A possible correlation between the correction of endothelial dysfunction and normalization of high blood pressure levels by 1,3,4-oxadiazole derivative, an L-type Ca2+ channel blocker in deoxycorticosterone acetate and N(G)-nitro-l-arginine hypertensive rats

We have previously demonstrated the vasorelaxant activity of 1,3,4-oxadiazole derivative (NOX-1) through L-type Ca2+ channel blockage. In the present study, we investigated whether the correction of endothelial dysfunction is dependent on the normalization of high blood pressure levels by 1,3,4-oxadiazole derivative (NOX-1) in deoxycorticosterone acetate (DOCA-salt) and N(G)-nitro-l-arginine (L-NNA) hypertensive rats. In DOCA-salt and L-NNA hypertensive rats, the mean systolic blood pressure (MSBB) was 185.3+/-4.7 and 170.2+/-4.1 mmHg, whereas after administration of NOX-1 to hypertensive rats, MSBB was 127.8+/-4.5 and 120.2+/-5.1 mmHg, respectively. To study the endothelial dysfunction, concentration-response curves of norepinephrine (NE) and acetylcholine (Ach) were constructed in rat aortic rings isolated from normotensive, hypertensive (DOCA and L-NNA) and NOX-1 treated rats. NE-induced contractions and Ach-induced relaxations were significantly (p<0.05) decreased and increased, respectively in the aorta of NOX-1 treated rats. Vasorelaxant activity of NOX-1 was not abolished by pretreatment of aortic rings with L-NNA, 1H-[1,2,4] oxadiazolo [4,3-A] quinoxalin-1-one (ODQ), indomethacin or glibenclamide. The results suggest that the endothelial dysfunction can be corrected by the L-type Ca2+ channel blocker with endothelium-independent action and that is dependent on the normalization of high blood pressure levels. The antihypertensive and vasorelaxant effects of NOX-1 are mainly endothelial-independent and it can be used to treat hypertension, a state associated with endothelial dysfunction.