Cardiovascular impact of drugs used in the treatment of diabetes

A systematic analysis of anti-diabetic medicinal plants from cells to clinical trials

Background

Diabetes is one of the fastest-growing health emergencies of the 21st century, placing a severe economic burden on many countries. Current management approaches have improved diabetic care, but several limitations still exist, such as decreased efficacy, adverse effects, and the high cost of treatment, particularly for developing nations. There is, therefore, a need for more cost-effective therapies for diabetes management. The evidence-based application of phytochemicals from plants in the management of diseases is gaining traction.

Methodology

Various plants and plant parts have been investigated as antidiabetic agents. This review sought to collate and discuss published data on the cellular and molecular effects of medicinal plants and phytochemicals on insulin signaling pathways to better understand the current trend in using plant products in the management of diabetes. Furthermore, we explored available information on medicinal plants that consistently produced hypoglycemic effects from isolated cells to animal studies and clinical trials.

Results

There is substantial literature describing the effects of a range of plant extracts on insulin action and insulin signaling, revealing a depth in knowledge of molecular detail. Our exploration also reveals effective antidiabetic actions in animal studies, and clear translational potential evidenced by clinical trials.

Conclusion

We suggest that this area of research should be further exploited in the search for novel therapeutics for diabetes.

Diabetes: Chronic Metformin Treatment and Outcome Following Acute Stroke

Aim

To evaluate if in patients with known diabetes, pretreatment metformin will lead to less severe stroke, better outcome, and lower mortality following acute stroke.

Methods

The Qatar stroke database was interrogated for stroke severity and outcome in patients with ischemic stroke. Outcome was compared in nondiabetic vs. diabetic patients and in diabetic patients on metformin vs. other hypoglycemic agents. The National Institute of Health Stroke Scale was used to measure stroke severity and 90-day modified Rankin scale (mRS) score to determine outcome following acute stroke.

Results

In total, 4,897 acute stroke patients [nondiabetic: 2,740 (56%) and diabetic: 2,157 (44%)] were evaluated. There were no significant differences in age, risk factors, stroke severity and type, or thrombolysis between the two groups. At 90 days, mRS (shift analysis) showed significantly poor outcome in diabetic patients (p < 0.001) but no differences in mortality. In the diabetic group, 1,132 patients were on metformin and 1,025 on other hypoglycemic agents. mRS shift analysis showed a significantly better outcome in metformin-treated patients (p < 0.001) and lower mortality (8.1 vs. 4.6% p < 0.001). Multivariate negative binomial analyses showed that the presence of diabetes negatively affected the outcome (90-day mRS) by factor 0.17 (incidence risk ratio, IRR, 1.17; CI [1.08-1.26]; p < 0.001) when all independent variables were held constant. In diabetic patients, pre-stroke treatment with metformin improved the outcome (90-day mRS) by factor 0.14 (IRR 0.86 [CI 0.75-0.97] p = 0.006).

Conclusion

Similar to previous reports, our study shows that diabetes adversely affects stroke outcome. The use of prior metformin is associated with better outcome in patients with ischemic stroke and results in lower mortality. The positive effects of metformin require further research to better understand its mechanism.

Synthesis, Antioxidant, and Antidiabetic Activities of Ketone Derivatives of Succinimide

The prevalence of diabetes mellitus is persistently increasing globally creating a serious public health affliction. Diabetes mellitus is categorized into two major types designated as type I and Type II. Type I diabetes mellitus is characterized by complete lack of secretion of insulin, while Type II diabetes mellitus is the resistance of peripheral tissues to the action of insulin and inadequate compensatory secretion of insulin. Chronic hyperglycemia associated with diabetes causes failure of cardiovascular system, nervous system, kidneys, and eyes. At present, different types of drugs are used for the management of diabetes, but each of them is associated with more or less serious side effects. Therefore, we need to develop new therapeutic agents that have better efficacy and safety profile. In this study, three ketone derivatives of succinimides were synthesized based on Michael addition and characterized using NMR. All the synthesized compounds were checked for their in vitro α-amylase and α-glucosidase inhibitory activities. Further the synthesized compounds were also explored for their antioxidant activities, i.e, DPPH and ABTS assays. Based on the in vitro results, the synthesized compounds were further evaluated for in vivo antidiabetic activity. The synthesized compounds were (2-oxocyclohexyl)-1-phenylpyrrolidine-2,5-dione (BW1), benzyl-3-(2-oxocyclohexyl) pyrrolidine-2,5-dione (BW2), and (4-bromophenyl)-3-(2-oxocyclohexyl) pyrrolidine-2,5-dione (BW3). BW1 showed the highest inhibitory activity for DPPH causing 83.03 ± 0.48 at 500 μg/ml with IC50 value of 10.84 μg/ml and highest inhibitory activity for ABTS causing 78.35 ± 0.23 at 500 μg/ml with IC50 value of 9.40 μg/ml against ascorbic acid used as standard. BW1 also exhibited the highest activity against α-amylase and α-glucosidase inhibition causing 81.60 ± 0.00 at concentrations of 500 μg/ml with IC50 value of 13.90 μg/ml and 89.08 ± 1.04 at concentrations of 500 μg/ml with IC50 value of 10.49 μg/ml, respectively, against the standard drug acarbose.

Dual anticancer role of metformin: an old drug regulating AMPK dependent/independent pathways in metabolic, oncogenic/tumorsuppresing and immunity context

Metformin has been known to treat type 2 diabetes for decades and is widely prescribed antidiabetic drug. Recently, its anticancer potential has also been discovered. Moreover, metformin has low cost thus it has attained profound research interest. Comprehensing the complexity of the molecular regulatory networks in cancer provides a mode for advancement of research in cancer development and treatment. Metformin targets many pathways that play an important role in cancer cell survival outcome. Here, we described anticancer activity of metformin on the AMPK dependent/independent mechanisms regulating metabolism, oncogene/tumor suppressor signaling pathways together with the issue of clinical studies. We also provided brief overwiev about recently described metformin's role in cancer immunity. Insight in these complex molecular networks, will simplify application of metformin in clinical trials and contribute to improvement of anti-cancer therapy.

Cardiovascular Safety and Benefits of Noninsulin Antihyperglycemic Drugs for the Treatment of Type 2 Diabetes Mellitus: Part 2

Ideal drugs to improve outcomes in type 2 diabetes mellitus (T2DM) are those with antiglycemic efficacy, as well as cardiovascular safety that has to be determined in appropriately designed cardiovascular outcome trials as mandated by regulatory agencies. The more recent antihyperglycemic medications have shown promise with regards to cardiovascular disease (CVD) risk reduction in T2DM patients at a high cardiovascular risk. Sodium glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists are associated with better cardiovascular outcomes and mortality in T2DM patients than are dipeptidylpeptidase-4 inhibitors, leading to the Food and Drug Administration's approval of empagliflozin to reduce mortality, and of liraglutide to reduce CVD risk in high-risk T2DM patients. For heart failure outcomes, sodium glucose cotransporter-2 inhibitors are beneficial, while glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors are neutral. Ongoing and planned randomized controlled trials of these newer drugs should clarify the possibility of class effects and of CVD risk reduction benefits in low-moderate cardiovascular risk patients. While we eagerly await the results on ongoing studies, these medications should be appropriately prescribed in T2DM patients with baseline CVD or those at a high CVD risk after carefully evaluating the elevated risk for adverse events like gastrointestinal disturbances, bladder cancer, genital infections, and amputations. Studies to understand the pleotropic and novel pathophysiological mechanisms demonstrated by the sodium glucose cotransporter-2 inhibitors will shed light on the effects of the modulation of microvascular, inflammatory, and thrombotic milieu for improving the CVD risk in T2DM patients. This is part 2 of the series on noninsulin antihyperglycemic drugs for the treatment of T2DM.

Amelioration of Endothelial Dysfunction in Diabetes: Role of Takeda G Protein-Coupled Receptor 5

Diabetes mellitus (DM) eventually leads to chronic vascular complications, resulting in cardiovascular diseases. DM-associated endothelial dysfunction (ED) plays an important role in the development of chronic vascular complications. Low endothelial nitric oxide synthase (eNOS) activity, inflammation, and oxidative stress all contribute to ED. The G protein-coupled receptor Takeda G protein-coupled receptor 5 (TGR5) is a membrane receptor for bile acids that plays an important role in the regulation of glucose metabolism. Recent studies have shown that TGR5 is involved in the regulation of various mediators of ED, which suggests that TGR5 may represent a target for the treatment of DM-associated ED. In this review, we summarize the principal mechanisms of DM-associated ED, then propose TGR5 as a novel therapeutic target on the basis of its mechanistic involvement, and suggest potential directions for future research.

Association between fasting insulin and C-reactive protein among adults without diabetes using a two-part model: NHANES 2005-2010

INTRODUCTION

Chronic inflammation is associated with the development, progression and long-term complications of type 2 diabetes. Hyperglycemia is associated with chronic low-grade inflammation, and thus has become the focus of many screening and treatment recommendations. We hypothesize that insulin may also be associated with inflammation and may be an additional factor to consider in screening and treatment.

METHODS

This study used National Health and Nutrition Examination Survey data from 2005 to 2010 to analyze the association between fasting insulin and C-reactive protein (CRP). A two-part model was used due to the high number of values reported as 0.1 mg/L. Two models were analyzed, both with and without the addition of waist circumference to other covariates in the model.

RESULTS

The final sample included 4527 adults with a mean age of 43.31 years. In the first model, higher fasting insulin was associated with increased odds of CRP > 0.1 mg/L (OR = 1.02, p < .001) and with higher CRP (β = 0.03, p < .001). In the adjusted model, including waist circumference as a covariate, higher fasting insulin was not associated with CRP > 0.1 mg/L (OR = 1.00, p = .307) but the association between higher fasting insulin and higher continuous CRP remained significant (β = 0.01, p = .012).

CONCLUSION

This study found that higher fasting insulin is associated with higher CRP. These results suggest that treatment approaches that simultaneously decrease insulin levels as well as glucose levels may provide additive anti-inflammatory effects, and therefore may improve long-term outcomes for adults with type 2 diabetes.

Changing Fields-Diabetes Medications Invading the Cardiovascular Space

Cardiovascular disease (CVD) remains the leading cause of mortality in patients with type 2 diabetes, and treatment strategies that impact cardiovascular (CV) outcomes in this population is an area of growing interest. Pharmacologic agents that reduce CVD risk have been developed, and data supporting their use have grown extensively. Glucagon-like peptide 1 agonists and sodium-glucose cotransporter 2 inhibitors when added to metformin therapy provide the most CV benefit and should be considered in most patients. Data available suggest that sulfonylureas should be avoided in patients at risk for CVD and if a thiazolidinedione is utilized, pioglitazone may be preferred. When selecting an agent, the potential benefit, risk, and cost of each agent should be considered prior to initiation. The purpose of this review is to summarize the literature surrounding the CV effects of antidiabetic agents and to provide practical guidance on their use in patients with type 2 diabetes and CVD.

A new aspect of an old friend: the beneficial effect of metformin on anti-tumor immunity

T-cell-based cancer immunotherapies, such as immune checkpoint blockers (ICBs) and chimeric antigen receptor (CAR)-T-cells, have significant anti-tumor effects against certain types of cancer, providing a new paradigm for cancer treatment. However, the activity of tumor infiltrating T-cells (TILs) can be effectively neutralized in the tumor microenvironment (TME) of most solid tumors, rich in various immunosuppressive factors and cells. Therefore, to improve the clinical outcomes of established T-cell-based immunotherapy, adjuvants that can comprehensively relieve multiple immunosuppressive mechanisms of TME are needed. In this regard, recent studies have revealed that metformin has several beneficial effects on anti-tumor immunity. In this mini-review, we understand the immunosuppressive properties of TME and how metformin comprehensively enhances anti-tumor immunity. Finally, we will discuss this old friend’s potential as an adjuvant for cancer immunotherapy.

Biological Activities of Selected Plants and Detection of Bioactive Compounds from Ardisia elliptica Using UHPLC-Q-Exactive Orbitrap Mass Spectrometry

Plants and plant-based products have been used for a long time for medicinal purposes. This study aimed to determine the antioxidant and anti-α-glucosidase activities of eight selected underutilized plants in Malaysia: Leucaena leucocephala, Muntingia calabura, Spondias dulcis, Annona squamosa, Ardisia elliptica, Cynometra cauliflora, Ficus auriculata, and Averrhoa bilimbi. This study showed that the 70% ethanolic extract of all plants exhibited total phenolic content (TPC) ranging from 51 to 344 mg gallic acid equivalent (GAE)/g dry weight. A. elliptica showed strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) scavenging activities, with half maximal inhibitory concentration (IC₅₀) values of 2.17 and 49.43 μg/mL, respectively. Most of the tested plant extracts showed higher inhibition of α-glucosidase enzyme activity than the standard, quercetin, particularly A. elliptica, F. auriculata, and M. calabura extracts with IC₅₀ values of 0.29, 0.36, and 0.51 μg/mL, respectively. A total of 62 metabolites including flavonoids, triterpenoids, benzoquinones, and fatty acids were tentatively identified in the most active plant, i.e., A. elliptica leaf extract, by using ultra-high-performance liquid chromatography (UHPLC)–electrospray ionization (ESI) Orbitrap MS. This study suggests a potential natural source of antioxidant and α-glucosidase inhibitors from A. elliptica.

Association of prestroke metformin use, stroke severity, and thrombolysis outcome

OBJECTIVE

To evaluate whether pretreatment with metformin (MET) is associated with less stroke severity and better outcome after IV thrombolysis (IVT), we analyzed a cohort of 1,919 patients with stroke with type 2 diabetes mellitus in a multicenter exploratory analysis.

METHODS

Data from patients with diabetes and ischemic stroke treated with IVT were collected within the European Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration. We applied propensity score matching (PSM) to obtain balanced baseline characteristics of patients treated with and without MET.

RESULTS

Of 1,919 patients with stroke with type 2 diabetes who underwent IVT, 757 (39%) had received MET before stroke (MET+), whereas 1,162 (61%) had not (MET-). MET+ patients were younger with a male preponderance. Hypercholesterolemia and pretreatment with statins, antiplatelets, or antihypertensives were more common in the MET+ group. After PSM, the 2 groups were well balanced with respect to demographic and clinical aspects. Stroke severity on admission (NIH Stroke Scale 10.0 ± 6.7 vs 11.3 ± 6.5), 3-month degree of independence on modified Rankin Scale (2 [interquartile range (IQR) 1.0-4.0] vs 3 [IQR 1.0-4.0]), as well as mortality (12.5% vs 18%) were significantly lower in the MET+ group. The frequency of symptomatic intracerebral hemorrhages did not differ between groups. HbA1c levels were well-balanced between the groups.

CONCLUSIONS

Patients with stroke and diabetes on treatment with MET receiving IVT had less severe strokes on admission and a better functional outcome at 3 months. This suggests a protective effect of MET resulting in less severe strokes as well as beneficial thrombolysis outcome.

Obesity preventive function of novel edible mushroom, Basidiomycetes-X (Echigoshirayukidake): Manipulations of insulin resistance and lipid metabolism

Echigoshirayukidake is an edible mushroom found in Uonuma, Japan in 1994. It was assigned to a new species of Basidiomycetes (BDM-X) but is uniquely defect of forming bashidium. The high antioxidant activity and β-glucan content of BDM-X suggest possible functions preventing type 2 diabetes. In the present study, anti-obesity and insulin resistance preventive functions of BDM-X were examined using genetically defined obese model rat, OLETF (Otsuka Long Evans Tokushima Fatty) by feeding regular diet with and without supplementation of 5% dried BDM-X powder (BDMP) for 15 weeks. BDMP supplementation to the diet significantly (p < 0.01) suppressed the body weight gain and also visceral fat accumulation during the feeding period compared to control diet. Simultaneously, the insulin resistance and the plasma levels of adiponectin and triglycerides were significantly (p = 0.003) ameliorated in the BDMP supplemented diet group. A statistical multivariate analysis showed the weight of three types of adipose tissue (epididymal, retroperirenal, and mesenteric fat) positively correlated with HOMA-IR (Homeostasis Model Assessment of Insulin Resistance), and negatively correlated with plasma adiponectin. These results indicate BDM-X is a new resource applicable to the functional foods or the complementary biomedicines to prevent metabolic syndromes leading to type 2 diabetes.

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A new mushroom, Echigoshirayukidake (BDM-X), ameliorates postprandial sugar and insulin spike enhancing insulin sensitivity.

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BDM-X prevented body weight gain, hyperlipidemia, NEFA, and visceral fat deposition.

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HOMA-IR was improved by BDM-X.

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Anti-metabolic syndrome effect of BDM-X could be related to increase of adiponectin level.

Why the endothelium? The endothelium as a target to reduce diabetes-associated vascular disease

Over the past 66 years, our knowledge of the role of the endothelium in the regulation of cardiovascular function and dysfunction has advanced from the assumption that it is a single layer of cells that serves as a barrier between the blood stream and vascular smooth muscle to an understanding of its role as an essential endocrine-like organ. In terms of historical contributions, we pay particular credit to (1) the Canadian scientist Dr. Rudolf Altschul who, based on pathological changes in the appearance of the endothelium, advanced the argument in 1954 that "one is only as old as one's endothelium" and (2) the American scientist Dr. Robert Furchgott, a 1998 Nobel Prize winner in Physiology or Medicine, who identified the importance of the endothelium in the regulation of blood flow. This review provides a brief history of how our knowledge of endothelial function has advanced and now recognize that the endothelium produces a plethora of signaling molecules possessing paracrine, autocrine, and, arguably, systemic hormone functions. In addition, the endothelium is a therapeutic target for the anti-diabetic drugs metformin, glucagon-like peptide I (GLP-1) receptor agonists, and inhibitors of the sodium-glucose cotransporter 2 (SGLT2) that offset the vascular disease associated with diabetes.

Androgen Therapy in Male Patients Suffering from Type 2 Diabetes: A Review of Benefits and Risks

BACKGROUND

The current estimated numbers of patients with Type 2 Diabetes (T2D) is believed to be close to 10% of the whole populations of many geographical regions, causing serious concerns over the resulting elevated morbidity and mortality as well as the impact on health care systems around the world. In addition to negatively affecting the quality of life, diabetes is associated with cardiovascular and cerebrovascular complications, indicating that appropriate drug therapy should not only deal with metabolic dysfunction but also protect the vascular system, kidney function and skeletal muscle mass from the effects of the epigenetic changes induced by hyperglycaemia.

OBJECTIVE

To provide an insight into the management of hypogonadism associated with T2D, this review focuses on clinical observations related to androgen therapy in qualified diabetic patients, and discusses the lines of evidence for its benefits and risks. The potential interactions of testosterone with medicines used by patients with T2D will also be discussed.

CONCLUSION

From recent clinical findings, it became evident that a considerable percentage of patients suffering from T2D manifested low serum testosterone and experienced diminished sexual activity, as well as reduced skeletal muscle mass and lower bone density. Although there are some controversies, Testosterone Replacement Therapy (TRT) for this particular population of patients appears to be beneficial overall only if it is implemented carefully and monitored regularly.

Nelumbo nucifera Receptaculum Extract Suppresses Angiotensin II-Induced Cardiomyocyte Hypertrophy

Nelumbo nucifera Gaertn. (lotus) is an important medicinal plant, and many parts of the plant have been investigated for their therapeutic effects. However, the therapeutic effect of receptacles of lotuses on pathological cardiomyocyte hypertrophy has not been investigated yet. Therefore, the current study aimed to determine the protective effect of lotus against angiotensin II (Ang II)-induced cardiomyocyte hypertrophy in vitro. Ang II was used to induce hypertrophy of H9c2 cells. The lotus receptacle powder (MeOH extract of receptaculum Nelumbinis; MRN) used in the experiments was prepared by MeOH extraction and subsequent evaporation. To evaluate the effect of MRN on cardiomyocyte hypertrophy, cell size, protein synthesis, and hypertrophic marker expressions were examined. The antioxidant ability of MRN was determined by using CM-H₂DCFDA, a general oxidative stress indicator. Ang II-induced cardiomyocyte hypertrophy was significantly attenuated by 5 µg/mL of MRN, as confirmed by the reductions in cell size, protein synthesis, and hypertrophic marker expression. MRN also attenuated Ang II-induced excessive intracellular reactive oxygen species (ROS) production through the suppression of protein kinase C (PKC), extracellular-signal-regulated kinase (ERK), and NF-κB activation and subsequent type I angiotensin receptor (AT1R), receptor for advanced glycation end products (RAGE), and NADPH oxidase (NOX) expression. MRN exerted a significant protective effect against Ang II-induced cardiomyocyte hypertrophy through suppression of PKC–ERK signaling, and this subsequently led to attenuation of intracellular ROS production.

Combinational effect of curcumin and metformin against gentamicin-induced nephrotoxicity: Involvement of antioxidative, anti-inflammatory and antiapoptotic pathway

Gentamicin (GM) is an antibiotic related to aminoglycoside group that is used in treating Gram-negative bacterial infections. However, treatment with gentamicin is considered to be limited as it induces an oxidative stress-mediated apoptosis in kidney which causes a nephrotoxicity. Metformin is a well-known biguanide that is used for treating diabetes mellitus, especially type 2. Supplement with plant metabolites or natural antioxidants produce a protective activity against many types of diseases in vivo. Curcumin is a main medicinal constituent of Curcuma longa, has reported for number of biological effects, such as antioxidant, anti-inflammatory, and antitumor. The study aims at evaluating the metformin and curcumin alone or in combination on nephrotoxicity induced by GM. The outcome of the study shows that both metformin and curcumin, when used unaided, were effectively decreasing GM-induced nephrotoxicity. The two drugs combination was showed synergistic effect in ameliorating a GM-induced kidney injury, as supported by expressively improved renal dysfunction. Metformin and curcumin showed strong protection against oxidative stress in GM treated animals through decreasing the activities and expression of various antioxidative enzymes. Moreover, combination of two drugs showed an anti-inflammatory response through reducing a level of pro-inflammatory cytokines including tumor necrosis factor-alpha, interleukin 1-beta, and interleukin 6 in GM intoxicated group of animals. Furthermore, GM agitated apoptosis was affectedly diminished by the combinational treatment of metformin and curcumin via down-regulating activity of cleaved Caspase-3 and pro-apoptotic factor Bax, whereas increasing anti-apoptotic factor Bcl-2 signaling pathways. The above results suggested that combinational treatment of metformin and curcumin might be have a synergizing effect and substantial potential against nephrotoxicity induced by GM. PRACTICAL APPLICATIONS: Curcumin and metformin combination exhibited substantial synergistic effect against GM-induced nephrotoxicity through reducing oxidative stress, inflammation, as well as apoptosis in kidney cells. Therefore, the method of combination of curcumin and metformin might be functional to treat or inhibit GM prompted nephrotoxicity in future.

Antioxidative potential of antidiabetic agents: A possible protective mechanism against vascular complications in diabetic patients

Many vascular complications are related to exposure of tissues to elevated levels of glucose, a condition that promotes oxidative stress. The primary goal of antidiabetic medication is for normalization of blood glucose. However, antidiabetic medications may have antioxidant effects that go beyond their hypoglycemic influences. Therefore, antidiabetic drugs may be doubly beneficial in preventing diabetic complications. Vascular dysfunction due to uncontrolled diabetes is a serious complication of the disease and one which has a severe impact on quality of life. Readjustment of the oxidative balance in subjects with diabetes, and the positive effects thereof is a topic of intense interest at present. In the current review, we highlight the antioxidant effects of antidiabetic medications which may prevent or delay the onset of vascular dysfunction.

Impact of currently used anti-diabetic drugs on myoendothelial communication

Diabetes is associated with a high risk of cardiovascular complications and ideally anti-diabetic drugs should not only reduce metabolic abnormalities but also reduce the negative impact of diabetes on vascular function; however, lowering blood glucose levels does not necessarily reduce cardiovascular events. Endothelial dysfunction, defined as a reduction in endothelium-dependent vasodilation, is the earliest indicator of vascular disease and this raises the question: Do the currently used anti-diabetic drugs protect endothelial function? Metformin, in use for 60 years, is the first choice drug for type 2 diabetes and based on pre-clinical and clinical data metformin has proven cardiovascular protective actions; in contrast SGLT2 inhibitors were only introduced in 2013 but show great promise. This review compares metformin with SGLT2 inhibitors and the data supporting their protective effects on the endothelium.

Chlorogenic acid attenuates glucotoxicity in H9c2 cells via inhibition of glycation and PKC α upregulation and safeguarding innate antioxidant status

A series of cardiovascular complications associated with hyperglycemia is a critical threat to the diabetic population. Here we elucidate the link between hyperglycemia and cardiovascular diseases onset, focusing on oxidative stress and associated cardiac dysfunctions. The contribution of advanced glycation end products (AGE) and protein kinase C (PKC) signaling is extensively studied. For induction of hyperglycemia, H9c2 cells were incubated with 33 mM glucose for 48 h to simulate the diabetic condition in in vitro system. Development of cardiac dysfunction was confirmed with the significant increase of lactate dehydrogenase (LDH) release to the medium and associated decrease in cell viability. Various parameters like free radical generation, alteration in innate antioxidant system, lipid peroxidation, AGE production and PKC α -ERK axis were investigated during hyperglycemia and with chlorogenic acid. Hyperglycemia has significantly enhanced reactive oxygen species (ROS- 4 fold) generation, depleted SOD activity (1.3 fold) and expression of enzymes particularly CuZnSOD (SOD1) and MnSOD (SOD2), increased production of AGE (2.18 fold). Besides, PKC α dependent ERK signaling pathway was found activated (1.43 fold) leading to cardiac dysfunction during hyperglycemia. Chlorogenic acid (CA) was found beneficial against hyperglycemia most probably through its antioxidant mediated activity. The outcome of this preliminary study reveals the importance of integrated approach emphasizing redox status, glycation and signaling pathways like PKC α - ERK axis for control and management of diabetic cardiomyopathy (DCM) and potential of bioactives like CA.

Acute Kidney Injury in Patients on SGLT2 Inhibitors: A Propensity-Matched Analysis

OBJECTIVE

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are new medications that improve cardiovascular and renal outcomes in patients with type 2 diabetes (T2D). However, the Food and Drug Administration has issued alerts regarding increased acute kidney injury (AKI) risk with canagliflozin and dapagliflozin. We aimed to assess the real-world risk of AKI in new SGLT2 inhibitor users in two large health care utilization cohorts of patients with T2D.

RESEARCH DESIGN AND METHODS

We used longitudinal data from the Mount Sinai chronic kidney disease registry and the Geisinger Health System cohort. We selected SGLT inhibitor users and nonusers (patients with T2D without SGLT2 inhibitor prescription). We determined AKI by the KDIGO (Kidney Disease: Improving Global Outcomes) definition (AKIKDIGO). We performed 1:1 nearest-neighbor propensity matching and calculated unadjusted hazard ratios (HRs) and adjusted HRs (aHRs; accounting for covariates poorly balanced) for AKI in primary and sensitivity analyses.

RESULTS

We identified 377 SGLT2 inhibitor users and 377 nonusers in the Mount Sinai cohort, of whom 3.8 and 9.7%, respectively, had an AKIKDIGO event over a median follow-up time of 14 months. The unadjusted hazards of AKIKDIGO were 60% lower in users (HR 0.4 [95% CI 0.2-0.7]; P = 0.01), which was unchanged (aHR 0.4 [95% CI 0.2-0.7]; P = 0.004) postadjustment. Similarly, we identified 1,207 SGLT2 inhibitor users and 1,207 nonusers in the Geisinger cohort, of whom 2.2 and 4.6% had an AKIKDIGO event. AKIKDIGO unadjusted hazards were lower in users (HR 0.5 [95% CI 0.3-0.8]; P < 0.01) with modest attenuation postadjustment for covariates (aHR 0.6 [95% CI 0.4-1.1]; P = 0.09). These estimates did not qualitatively change across several sensitivity analyses.

CONCLUSIONS

Our findings do not suggest an increased risk of AKI associated with SGLT2 inhibitor use in patients with T2D in two large health systems.

Cardiovascular benefits and safety of non-insulin medications used in the treatment of type 2 diabetes mellitus

Diabetes mellitus is a growing in exponential proportions. If the current growth trend continues, it may result in every third adult in the United States having diabetes mellitus by 2050, and every 10^th adult worldwide. Type 2 diabetes mellitus (T2DM) confers a 2- to 3-fold increased risk of cardiovascular (CV) events compared with non-diabetic patients, and CV mortality is responsible for around 80% mortality in this population. Patients with T2DM can have other features of insulin resistance-metabolic syndrome like hypertension, lipid abnormalities, and obesity which are all associated with increased CV disease and stroke risk even in the absence of T2DM. The management of a T2DM calls for employing a holistic risk factor control approach. Metformin is the first line therapy for T2DM and has been shown to have cardiovascular beneficial effects. Intense debate regarding the risk of myocardial infarction with rosiglitazone led to regulatory agencies necessitating cardiovascular outcome trials with upcoming anti-diabetic medications. Glucagon like peptide-1 agonists and sodium glucose co-transporter-2 inhibitors have shown promising CV safety and additional CV benefit in recent clinical trials. These drugs have favorable effects on traditional CV risk factors. The findings from these studies further support that fact that CV risk factor control plays an important role in reducing morbidity and mortality in T2DM patients. This review article will discuss briefly the cardiovascular safety and benefits of the oral medications which are currently being used for T2DM and will then discuss in detail about the newer medications being investigated for the treatment of T2DM.

Cardiovascular benefits of the newer medications for treating type 2 diabetes mellitus

Diabetes mellitus is growing in pandemic proportions and is associated with significant morbidity, mortality, and health care expenditure. Type 2 diabetes mellitus (T2DM) is the most common, accounting for about 90-95% of diagnosed diabetes in United States adults. Individuals with T2DM have a 2- to 3-fold increased risk of cardiovascular (CV) events compared with their non-diabetic counterparts, and CV mortality is responsible for around 80% of the mortality in T2DM. Emerging evidence suggest that in T2DM patients, hyperglycemia plays a little role in the progression of CV disease, and metabolic risk factors like insulin resistance, hypertension, obesity, and dyslipidemia are the major culprits in the initiation and progression of CV disease. This calls for development of drugs which control hyperglycemia as well as the various metabolic risk factors in T2DM patients to improve CV outcomes. Recent clinical trials of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) and sodium glucose cotransporter-2 (SGLT-2) inhibitors showed encouraging CV outcomes in T2DM patients, which are attributed to the diverse extra-pancreatic effects of these medications. This review article will discuss the CV benefits of the newer incretin based therapies and SGLT-2 inhibitors as observed in their CV safety trials. As T2DM or insulin resistance syndrome, CV disease, and HF and frequently coexistent, it would be interesting to design studies evaluating the combinations of GLP-1 RAs, SGLT-2 inhibitors, and pioglitazone in T2DM patient at an elevated CV risk, and in non-diabetic patients with insulin resistance to study the possible CV protective role of these combinations.

Metabolic and Biochemical Stressors in Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) or diabetes-induced cardiac dysfunction is a direct consequence of uncontrolled metabolic syndrome and is widespread in US population and worldwide. Despite of the heterogeneous and distinct features of DCM, the clinical relevance of DCM is now becoming established. DCM progresses to pathological cardiac remodeling with the higher risk of heart attack and subsequent heart failure in diabetic patients. In this review, we emphasize lipid substrate quality and the phenotypic, metabolic, and biochemical stressors of DCM in the rodent and human pathophysiology. We discuss lipoxygenase signaling in the inflammatory pathway with multiple contributing and confounding factors leading to DCM. Additionally, emerging biochemical pathways are emphasized to make progress toward therapeutic advancement to treat DCM.

Acupuncture treatment for insulin sensitivity of women with polycystic ovary syndrome and insulin resistance: a study protocol for a randomized controlled trial

BACKGROUND

Our prospective pilot study of acupuncture affecting insulin sensitivity on polycystic ovary syndrome (PCOS) combined with insulin resistance (IR) showed that acupuncture had a significant effect on improving the insulin sensitivity of PCOS. But there is still no randomized controlled trial to determine the effect of acupuncture on the insulin sensitivity in women with PCOS and IR. In this article, we present the protocol of a randomized controlled trial to compare the effect of true acupuncture on the insulin sensitivity of these patients compared with metformin and sham acupuncture. Acupuncture may be an effective therapeutic alternative that is superior to metformin and sham acupuncture in improving the insulin sensitivity of PCOS combined with IR.

METHODS

This study is a multi-center, controlled, double-blind, and randomized clinical trial aiming to evaluate the effect of acupuncture on the insulin sensitivity in PCOS combined with IR. In total 342 patients diagnosed with PCOS and IR will be enrolled. Participants will be randomized to one of the three groups: (1) true acupuncture + metformin placebo; (2) sham acupuncture + metformin, and (3) sham acupuncture + metformin placebo. Participants and assessors will be blinded. The acupuncture intervention will be given 3 days per week for a total of 48 treatment sessions during 4 months. Metformin (0.5 g per pill) or placebo will be given, three times per day, and for 4 months. Primary outcome measures are changes in homeostasis model assessment of insulin resistance (HOMA-IR) and improvement rate of HOMA-IR by oral glucose tolerance test (OGTT) and insulin releasing test (Ins). Secondary outcome measures are homeostasis model assessment-β (HOMA-β), area under the curve for glucose and insulin, frequency of regular menstrual cycles and ovulation, body composition, metabolic profile, hormonal profile, questionnaires, side effect profile, and expectation and credibility of treatment. Outcome measures are collected at baseline, at the end of treatments, and 3 months after the last acupuncture treatment. On completion of the screening visit, randomization will be conducted using a central randomization system.

DISCUSSION

This study will investigate the effects of acupuncture on the insulin sensitivity of PCOS and IR women compared with metformin and sham acupuncture. We will test whether true acupuncture with needles placed in skeletal muscles and stimulated manually and by electrical stimulation is more effective than metformin and sham acupuncture with superficial needle placement with no manual or electrical stimulation in improving the insulin sensitivity in PCOS women with IR.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02491333 ; Chinese Clinical Trial Registry, ChiCTR-ICR-15006639. Registered on 24 June 2015.

Metformin is not just an antihyperglycaemic drug but also has protective effects on the vascular endothelium

Metformin, a synthetic dimethyl biguanide, has been in clinical use for over 55 years, and today is considered the first-choice drug for the treatment of type 2 diabetes used by an estimated 125 million people worldwide. Metformin is orally effective, not metabolized, excreted unchanged by the kidney, relatively free of side effects and well tolerated by the majority of patients. Of importance is that the United Kingdom Prospective Diabetes Study 20-year study of type 2 diabetics, completed in 1998, compared patients treated with insulin, sulfonylureas and metformin and concluded that metformin provided vascular protective actions. Cardiovascular disease is the primary basis for the high morbidity and mortality that is associated with diabetes and that metformin proved to be protective resulted in a dramatic increase in its use. The vascular protective actions of metformin are thought to be secondary to the antihyperglycaemic effects of metformin that are mediated via activation of AMP kinase and subsequent inhibition of hepatic gluconeogenesis, fatty acid oxidation as well as an insulin sensitizing action in striated muscle and adipose tissue. As reflected by a number of clinical studies, patients treated with metformin also have improvement in endothelial function as measured by the use of plethysmography and measurement of flow-mediated vasodilatation. These data as well as data from animal studies are supportive that metformin has a direct protective action on the vascular endothelium. In this review article, we discuss the pharmacology of metformin and critique the literature as to its cellular sites and mechanism(s) of action.

Continued efforts to translate diabetes cardiovascular outcome trials into clinical practice

Diabetic patients suffer from a high rate of cardiovascular events and such risk increases with HbA1c. However, lowering HbA1c does not appear to yield the same benefit on macrovascular endpoints, as observed for microvascular endpoints. As the number of glucose-lowering medications increases, clinicians have to consider several open questions in the management of type 2 diabetes, one of which is the cardiovascular risk profile of each regimen. Recent placebo-controlled cardiovascular outcome trials (CVOTs) have responded to some of these questions, but careful interpretation is needed. After general disappointment around CVOTs assessing safety of DPP-4 inhibitors (SAVOR, TECOS, EXAMINE) and the GLP-1 receptor agonist lixisenatide (ELIXA), the EMPA-REG Outcome trial and the LEADER trial have shown superiority of the SGLT2-I empagliflozin and the GLP-1RA liraglutide, respectively, on the 3-point MACE outcome (cardiovascular death, non-fatal myocardial infarction or stroke) and cardiovascular, as well as all-cause mortality. While available mechanistic studies largely support a cardioprotective effect of GLP-1, the ability of SGLT2 inhibitor(s) to prevent cardiovascular death was unexpected and deserves future investigation. We herein review the results of completed CVOTs of glucose-lowering medications and suggest a possible treatment algorithm based on cardiac and renal co-morbidities to translate CVOT findings into clinical practice.

Ablation of Adenosine Monophosphate-Activated Protein Kinase α1 in Vascular Smooth Muscle Cells Promotes Diet-Induced Atherosclerotic Calcification In Vivo

RATIONALE

Atherosclerotic calcification is highly linked with plaque rapture. How calcification is regulated is poorly characterized.

OBJECTIVE

We sought to determine the contributions of AMP-activated protein kinase (AMPK) in atherosclerotic calcification.

METHODS AND RESULTS

Aortic calcification was evaluated in aortic roots and brachiocephalic arteries of atherosclerotic prone ApoE(-/-) mice or in mice with dual deficiencies of ApoE and AMPKα isoforms in whole body (ApoE(-/-)/AMPKα1(-/-) and ApoE(-/-)/AMPKα2(-/-)) or vascular smooth muscle cell (VSMC)-specific or macrophage-specific knockout of AMPKα1 fed with Western diet for 24 weeks. Genetic deficiency of AMPKα1 but not of AMPKα2 promoted atherosclerotic calcification and the expression of Runx2 (Runt-related transcription factor). Conversely, chronic administration of metformin, which activated AMPK, markedly reduced atherosclerotic calcification and Runx2 expression in ApoE(-/-) mice but had less effects in ApoE(-/-)/AMPKα1(-/-) mice. Furthermore, VSMC-specific but not macrophage-specific ablation of AMPKα1 promoted aortic calcification in vivo. Ablation of AMPKα1 in VSMC prevented Runx2 from proteasome degradation in parallel with aberrant osteoblastic differentiation of VSMC, whereas AMPK activation promoted Runx2 post-translational modification by small ubiquitin-like modifier (SUMO, SUMOylation), which is associated with its instability. Mechanically, we found that AMPKα1 directly phosphorylated protein inhibitor of activated STAT-1 (PIAS1), the SUMO E3-ligase of Runx2, at serine 510, to promote its SUMO E3-ligase activity. Finally, mutation of protein inhibitor of activated STAT-1 at serine 510 suppressed metformin-induced Runx2 SUMOylation and subsequently prevented metformin's effect on reducing oxidized low-density lipoprotein-triggered Runx2 expression in VSMC.

CONCLUSIONS

AMPKα1 phosphorylated protein inhibitor of activated STAT-1 to promote Runx2 SUMOylation and subsequently lead to its instability. AMPKα1 deficiency in VSMC increased Runx2 expression and promoted atherosclerotic calcification in vivo.

c-Src tyrosine kinase mediates high glucose-induced endothelin-1 expression

Endothelin-1 (ET-1) plays an important role in the pathophysiology of diabetes-associated cardiovascular disorders. The molecular mechanisms leading to ET-1 upregulation in diabetes are not entirely defined. c-Src tyrosine kinase regulates important pathophysiological aspects of vascular response to insults. In this study, we aimed to elucidate whether high glucose-activated c-Src signaling plays a role in the regulation of ET-1 expression. Human endothelial cells EAhy926 (ECs) were exposed to normal or high levels of glucose for 24h. Male C57BL/6J mice were rendered diabetic with streptozotocin and then treated with a specific c-Src inhibitor (Src I1) or c-Src siRNA. Real-time PCR, Western blot, and ELISA, were used to investigate ET-1 regulation. The c-Src activity and expression were selectively downregulated by pharmacological inhibition and siRNA-mediated gene silencing, respectively. High glucose dose-dependently up-regulated c-Src phosphorylation and ET-1 gene and protein expression levels in human ECs. Chemical inhibition or silencing of c-Src significantly decreased the high-glucose augmented ET-1 expression in cultured ECs. In vivo studies showed significant elevations in the aortic ET-1 mRNA expression and plasma ET-1 concentration in diabetic mice compared to non-diabetic animals. Treatment with Src I1, as well as in vivo silencing of c-Src, significantly reduced the upregulated ET-1 expression in diabetic mice. These data provide new insights into the regulation of ET-1 expression in endothelial cells in diabetes. Pharmacological targeting of c-Src activity and/or expression may represent a potential therapeutic strategy to reduce ET-1 level and to counteract diabetes-induced deleterious vascular effects.

Long-lasting hypoglycemic effect of modified FGF-21 analog with polyethylene glycol in type 1 diabetic mice and its systematic toxicity

Fibroblast growth factor-21 (FGF-21) is a novel metabolic regulator and has the potential to become a powerful therapy to treat diabetes mellitus. However, we found that the clinical application of wild type FGF-21 was influenced by its low intrinsic bio-stability and poor hypoglycemic potency. In this study, The N-terminus of FGF-21 analog (mFGF-21) was PEGylated in a site-specific manner by 20kD methoxy poly-ethylene glycol-propionaldehyde (mPEG-ALD). PEGylated mFGF-21 was isolated by Capto Q anion exchange chromatography. The properties of PEGylated mFGF-21 including the in vitro bio-stability and biological activity were evaluated. As well as the anti-diabetic effect of PEGylated mFGF-21 were studied in streptozotocin (STZ)-induced type 1 diabetic mice. Results demonstrated that PEGylated mFGF-21 had a similar capacity of stimulating glucose uptake in HepG2 cells with mFGF-21 and PEGylation of mFGF-21 significantly enhanced the anti-protease ability and the long acting anti-diabetic effect in type 1 diabetic mice. Furthermore, the preliminary safety of PEGylated mFGF-21 following subcutaneously injection was assessed using healthy mice by measuring the body weight, histopathology and clinical biochemical parameters, and the results showed no subacute toxicity to major organs or tissues and no significant changes in physiological and biochemical parameters in healthy mice. Taken together, under the premise of remaining the in vitro biological activity of mFGF-21, PEGylation significantly improves the long lasting hypoglycemic effect of mFGF-21 in type 1 diabetic mice. Our valuation shows that PEGylated mFGF-21 is a potential drug for the effective treatment of type 1 diabetes.

Metformin improves endothelial function in aortic tissue and microvascular endothelial cells subjected to diabetic hyperglycaemic conditions

The cellular mechanisms whereby metformin, the first line drug for type 2 diabetes (T2DM), mediates its antidiabetic effects remain elusive, particularly as to whether metformin has a direct protective action on the vasculature. This study was designed to determine if a brief 3-h exposure to metformin protects endothelial function against the effects of hyperglycaemia. We investigated the protective effects of metformin on endothelial-dependent vasodilatation (EDV) in thoracic aortae from T2DM db/db mice and on high glucose (HG, 40 mM) induced changes in endothelial nitric oxide synthase (eNOS) signaling in mouse microvascular endothelial cells (MMECs) in culture. Exposure of aortae from db+/? non-diabetic control mice to high glucose (HG, 40 mM) containing Krebs for 3-h significantly (P<0.05) reduced acetylcholine (ACh)-induced EDV compared to ACh-induced EDV in aortae maintained in normal glucose (NG, 11 mM) Krebs. The reduction of EDV was partially reversed following a 3-h exposure to 50 μM metformin; metformin also improved ACh-induced EDV in aortae from diabetic db/db mice. Immunoblot analysis of MMECs cultured in HG versus NG revealed a significant reduction of the ratio of phosphorylated (p-eNOS)/eNOS and p-Akt/Akt, but not the expression of total eNOS or Akt. The 3-h exposure of MMECs to metformin significantly (P<0.05) reversed the HG-induced reduction in phosphorylation of both eNOS and Akt; however, no changes were detected for phosphorylation of AMPK or the expression of SIRT1. Our data indicate that a 3-h exposure to metformin can reverse/reduce the impact of HG on endothelial function, via mechanisms linked to increased phosphorylation of eNOS and Akt.

A Study on the Level of Oxidative Stress and Inflammatory Markers in Type 2 Diabetes Mellitus Patients with Different Treatment Modalities

INTRODUCTION

The prevalence of type 2 diabetes mellitus is increasing worldwide in all the age group. UKPDS study had shown that good glycaemic control is maintained by the administration of insulin in addition to hypoglycaemic drugs. But, hyperinsulinemia might cause vascular complications in T2DM. Oxidative stress and inflammation are common in diabetes and plays an important role in vascular complications.

AIM

The study has been designed to estimate and compare the level of oxidative stress and inflammation in type 2 diabetic patients under different treatment modalities.

MATERIALS AND METHODS

Sixty Type 2 diabetic subjects undergoing treatment were selected from Government Hospital and VMKV Medical College & Hospital at Salem. The subjects were divided into two groups based on treatment modalities, hypoglycaemic drugs subjects as Group-I (30) and hypoglycaemic drugs & Insulin subjects in Group-II (30). BMI was calculated by standard formula and Fasting blood sugar (FBS), postprandial blood sugar (PPBS), glycated haemoglobin (HbA1c), Lipid profile, oxidative stress (MDA) and inflammatory markers were measured by well established methods. SPSS 16.0 version was used for statistical analysis.

RESULT

In our study we have found significantly high levels of BMI, MDA and hsCRP (25.5±2.79, 2.73±1.65, 1.98±0.85) in Group II subjects when compared to Group I subjects (23.4±3.09, 2.23±1.76, 1.168±1.124).

CONCLUSION

Since risk factors like BMI, MDA and hsCRP were high in Diabetes mellitus patients on both oral hypoglycaemic drugs and insulin, they are more susceptible to cardiovascular diseases. Evaluation of these markers at regular interval can reduce the incidence of vascular complications in Type 2 DM patients.

Anti-Diabetic and Hepato-Renal Protective Effects of Ziyuglycoside II Methyl Ester in Type 2 Diabetic Mice

Type 2 diabetes is a metabolic disorder caused by abnormal carbohydrate metabolism, and closely associated with abnormal lipid metabolism and hepato-renal dysfunction. This study investigated the anti-diabetic and hepato-renal protective properties of ziyuglycoside I (ZG01) derivative on type 2 diabetes. ZG01 was isolated from roots of Sanguisorba officinalis and chemically modified by deglycosylation and esterification to obtained ziyuglycoside II methyl ester (ZG02-ME). Here, we showed that ZG02-ME has stronger anti-diabetic activity than the original compound (ZG01) through decreasing blood glucose, glycated hemoglobin (HbA1c), and insulin levels in a mouse model of type 2 diabetes (db/db mice). We further found that ZG02-ME treatment effectively ameliorated serum insulin, leptin and C-peptide levels, which are key metabolic hormones, in db/db mice. In addition, we showed that elevated basal blood lipid levels were decreased by ZG02-ME treatment in db/db mice. Furthermore, treatment of ZG02-ME significantly decreased serum AST, ALT, BUN, creatinine, and liver lipid peroxidation in db/db mice. These results demonstrated that compared to ZG01, chemically modified ZG02-ME possess improved anti-diabetic properties, and has hepato-renal protective activities in type 2 diabetes.