Free radical activity and hemostatic factors in NIDDM patients with and without microalbuminuria

Effects of Panax ginseng and ginsenosides on oxidative stress and cardiovascular diseases: pharmacological and therapeutic roles

Traditionally, Asian ginseng or Korean ginseng, Panax ginseng has long been used in Korea and China to treat various diseases. The main active components of Panax ginseng is ginsenoside, which is known to have various pharmacological treatment effects such as antioxidant, vascular easing, anti-allergic, anti-inflammatory, anti-diabetes, and anticancer. Most reactive oxygen species (ROS) cause chronic diseases such as myocardial symptoms and cause fatal oxidative damage to cell membrane lipids and proteins. Therefore, many studies that inhibit the production of oxidative stress have been conducted in various fields of physiology, pathophysiology, medicine and health, and disease. Recently, ginseng or ginsenosides have been known to act as antioxidants in vitro and in vivo results, which have a beneficial effect on preventing cardiovascular disease. The current review aims to provide mechanisms and inform precious information on the effects of ginseng and ginsenosides on the prevention of oxidative stress and cardiovascular disease in animals and clinical trials.

High risk of coagulopathy among Type-2 Diabetes Mellitus clients at a municipal hospital in Ghana

Background

Persistent hyperglycaemia in diabetes mellitus causes coagulopathies due to glycation of haemoglobin, prothrombin, fibrinogen and other proteins involved in the clotting mechanism. Shortened activated partial thromboplastin time (APTT) and prothrombin time (PT) reflect hypercoagulable state, which is associated with an increased thrombotic risk and adverse cardiovascular effects. This study assessed the coagulation profile of type 2 diabetes mellitus (T2DM) clients at a municipal hospital in Ghana.

Methods

A hospital-based case-control study was conducted from January to April 2015 at the Agona Swedru Municipal Hospital. Sixty (60) persons with T2DM and 40 without were recruited and screened using appropriate protocols. Blood samples were collected for coagulation and biochemical tests. Demographic and clinical information were collected using pre-tested questionnaire. Data was analyzed with GraphPad Prism version 5.

Results

APTT and PT were significantly shorter among patients with T2DM compared to those without (20.88 ± 5.19 v 31.23 ± 5.41, P=0.0001; and 11.03 ± 2.06sec v 14.46 ± 1.86, P=0.0001 respectively). INR was decreased among patients with T2DM compared to those without (0.83 ± 0.18 v 1.13 ± 0.17, P=0.0001). No significant difference was found in platelet count between T2DM and non-diabetics (179.85 ± 66.15×10³ /mm³ v 168.55 ± 35.77×10³ /mm³, P=0.326). Serum magnesium was lower among the T2DM patients compared to the non-diabetics, while serum ionized calcium was significantly higher among the T2DM patients (P<0.05).

Conclusion

Clients with T2DM may have a high coagulation risk evidenced by shortened APTT, PT and a high ionized calcium compared with controls.

Funding

Study was funded by Lord Ampomah and Solomon Panford.

A review of the mechanisms and effectiveness of dietary polyphenols in reducing oxidative stress and thrombotic risk

Dietary sources of polyphenols, which are derivatives and/or isomers of flavones, isoflavones, flavonols, catechins and phenolic acids, possess antioxidant properties and therefore might be important in preventing oxidative-stress-induced platelet activation and attenuating adverse haemostatic function. Free radicals, including reactive oxygen and nitrogen species, promote oxidative stress, leading to platelet hyperactivation and the risk of thrombosis. The consumption of antioxidant/polyphenol rich foods might therefore impart anti-thrombotic and cardiovascular protective effects via their inhibition of platelet hyperactivation or aggregation. Most commonly-used anti-platelet drugs such as aspirin block the cyclooxygenase (COX)-1 pathway of platelet activation, similar to the action of antioxidants with respect to neutralising hydrogen peroxide (H2 O2 ), with a similar effect on thromboxane production via the COX-1 pathway. Polyphenols also target various additional platelet activation pathways (e.g. by blocking platelet-ADP, collagen receptors); thus alleviating fibrinogen binding to platelet surface (GPIIb-IIIa) receptors, reducing further platelet recruitment for aggregation and inhibiting platelet degranulation. As a result of the ability of polyphenols to target additional pathways of platelet activation, they may have the potential to substitute or complement currently used anti-platelet drugs in sedentary, obese, pre-diabetic or diabetic populations who can be resistant or sensitive to pharmacological anti-platelet therapy.

Association of hepatitis C with markers of hemostasis in HIV-infected and uninfected women in the women's interagency HIV study (WIHS)

BACKGROUND

Coinfection with HIV and hepatitis C virus (HCV) is common. HIV infection and treatment are associated with hypercoagulability; thrombosis in HCV is underinvestigated. Proposed markers of hemostasis in HIV include higher D-dimer, Factor VIII%, and plasminogen activator inhibitor-1 (PAI-1) antigen and lower total Protein S% (TPS) but have not been examined in HCV. We assessed the independent association of HCV with these 4 measures of hemostasis in a multicenter, prospective study of HIV: the Women's Interagency HIV Study.

METHODS

We randomly selected 450 HCV-infected (anti-HCV+ with detectable plasma HCV RNA) and 450 HCV-uninfected (anti-HCV-) women. HCV was the main exposure of interest in regression models.

RESULTS

Four hundred forty-three HCV+ and 425 HCV- women were included. HCV+ women had higher Factor VIII% (124.4% ± 3.9% vs. 101.8% ± 3.7%, P < 0.001) and lower TPS (75.7% ± 1.1% vs. 84.3% ± 1.1%, <0.001) than HCV- women, independent of HIV infection and viral load; there was little difference in PAI-1 or log10 D-dimer. After adjustment for confounders, these inferences remained. HIV infection was independently associated with higher Factor VIII% and log10 D-dimer and lower TPS.

CONCLUSIONS

HCV was independently associated with higher Factor VIII% and lower TPS consistent with hypercoagulability. Higher Factor VIII% and D-dimer and lower TPS were also strongly associated with HIV infection and levels of HIV viremia, independent of HCV infection. Further investigation is needed to determine if there is increased thrombotic risk from HCV. Studies examining hemostasis markers in HIV infection must also assess the contribution of HCV infection.

Impact of diabetes mellitus on outcomes in patients with acute myocardial infarction and systolic heart failure

AIMS

To determine independent associations of diabetes mellitus with outcomes in a propensity-matched cohort of patients with acute myocardial infarction (AMI) and systolic heart failure (HF).

METHODS AND RESULTS

In the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) trial, hospitalized AMI patients complicated by left ventricular ejection fraction ≤40% and symptoms of HF receiving standard therapy were randomized 3-14 days post-AMI to receive eplerenone 25-50 mg/day (n = 3319) or placebo (n = 3313). Of the 6632 patients, 2142 (32%) had a history of diabetes, who were older and sicker. Using propensity scores for diabetes, we assembled a cohort of 1119 pairs of patients with and without diabetes who were balanced on 64 baseline characteristics. Incident fatal or nonfatal recurrent AMI occurred in 136 (12%) and 87 (8%) of matched patients with and without diabetes, respectively, during 2.5 years of follow-up [hazard ratio (HR) when diabetes was compared with no-diabetes, 1.61; 95% confidence interval (CI), 1.23-2.10; P = 0.001]. Diabetes was associated with nonfatal AMI (HR, 1.68; 95% CI, 1.23-2.31; P = 0.001) but not with fatal AMI (HR, 1.42; 95% CI, 0.88-2.28; P = 0.146). Hazard ratios (95% CIs) for the association of diabetes with all-cause mortality, cardiovascular mortality, all-cause hospitalization, and cardiovascular hospitalization were 1.12 (0.93-1.37; P = 0.224), 1.11 (0.90-1.37; P = 0.318), 1.13 (1.00-1.27; P = 0.054), and 1.20 (1.01-1.44; P = 0.042), respectively.

CONCLUSION

In post-AMI patients with systolic HF, diabetes mellitus is a significant independent risk factor for recurrent short-term nonfatal AMI, but had no association with fatal AMI.

[Physical activity and endothelial dysfunction in type 2 diabetic patients: the role of nitric oxide and oxidative stress]

Type 2 diabetic patients have an increased level of systemic free radicals, which severely restrict the bioavailability of endothelium-derived nitric oxide (NO) and thus contribute to the development of an endothelial dysfunction. This review analyses the influence of physical training on molecular development mechanisms of the endothelial dysfunction and determines the significance of regular physical exercise for the endothelial function in type 2 diabetic patients. Systematic training reinforces the endogenic antioxidative capacity and results in a reduction in oxidative stress. Training - also combined with a change in diet - furthermore reduces hyperglycaemic blood sugar levels, thus curbing a major source of free radicals in diabetes. Moreover, physical exercise enhances vascular NO synthesis through an increased availability/activity of endothelial NO synthases (eNOS). Endurance, as well as resistance training with submaximal intensity or a combination of both forms of training is suitable to effectively improve the endothelial function in type 2 diabetic patients in the long term.

Antithrombotic therapy in patients with coronary artery disease and with type 2 diabetes mellitus

Diabetes mellitus (DM) is a life-threatening disease. Patients with DM have a 2- to 4-fold higher risk of developing cardiovascular disease compared to their non-diabetic counterparts. Several drugs are available for the treatment of stable coronary artery disease (CAD) and acute coronary syndrome (ACS). Among oral antiplatelet agents (acetylsalicylic acid, ticlopidine, clopidogrel, and prasugrel), prasugrel has shown the highest efficacy in patients with DM and ACS. The use of glycoprotein IIb-IIIa receptor inhibitors in diabetic subjects with ACS undergoing percutaneous coronary intervention (PCI) reduces adverse clinical events in a greater extent than in non-diabetics. Several direct and indirect antithrombins are recommended for the treatment of ACS such as unfractionated heparin (UFH), enoxaparin, fondaparinux, and bivalirudin. Enoxaparin and bivalirudin have been shown to be superior to UFH among patients with ST-elevation MI (STEMI) and non-ST elevation MI (NSTEMI) also in diabetic subgroup analyses.

Circulating vascular endothelial growth factor in the normo- and/or microalbuminuric patients with type 2 diabetes mellitus

Relationship between serum vascular endothelial growth factor (VEGF) level and parameters of endothelial injury and/or dysfunction in patients with diabetes mellitus type 2 with or without microalbuminuria was investigated. Eighty-four diabetic patients were divided in two subgroups (42 each): normoalbuminuric (NAU) and microalbuminuric (MAU). Forty-two blood donors were in control group. Serum VEGF and plasma von Willebrand factor, soluble thrombomodulin, plasminogen activator inhibitor 1, thrombin-activatable fibrinolysis inhibitor (TAFI) and tissue plasminogen activator (t-PA) were measured using enzyme-linked immunosorbent assay in all subjects. VEGF was significantly higher in NAU compared to controls. The difference between MAU and controls was not statistically significant, but there was a trend toward significance. Only TAFI correlated with VEGF in MAU. An observed significant increase of serum VEGF level already in NAU suggests that serum VEGF could be a sensitive predictor of endothelial dysfunction in type 2 diabetes.

Platelet tissue factor synthesis in type 2 diabetic patients is resistant to inhibition by insulin

OBJECTIVE

Patients with type 2 diabetes have an increased risk of cardiovascular disease and show abnormalities in the coagulation cascade. We investigated whether increased synthesis of tissue factor (TF) by platelets could contribute to the hypercoagulant state.

RESEARCH DESIGN AND METHODS

Platelets from type 2 diabetic patients and matched control subjects were adhered to different surface-coated proteins, and TF premRNA splicing, TF protein, and TF procoagulant activity were measured.

RESULTS

Different adhesive proteins induced different levels of TF synthesis. A mimetic of active clopidogrel metabolite (AR-C69931 MX) reduced TF synthesis by 56 +/- 10%, an aspirin-like inhibitor (indomethacin) by 82 +/- 9%, and the combination by 96 +/- 2%, indicating that ADP release and thromboxane A(2) production followed by activation of P2Y12 and thromboxane receptors mediate surface-induced TF synthesis. Interference with intracellular pathways revealed inhibition by agents that raise cAMP and interfere with phosphatidylinositol 3-kinase/protein kinase B. Insulin is known to raise cAMP in platelets and inhibited collagen III-induced TF premRNA splicing and reduced TF activity by 35 +/- 5 and 47 +/- 5% at 1 and 100 nmol/l. Inhibition by insulin was reduced in type 2 diabetes platelets resulting in an approximately 1.6-fold higher TF synthesis than in matched control subjects.

CONCLUSIONS

We characterized the extra- and intracellular mechanisms that couple surface activation to TF synthesis in adhering platelets. In healthy individuals, TF synthesis is inhibited by insulin, but in patients with type 2 diabetes inhibition is impaired. This leads to the novel finding that platelets from type 2 diabetic patients produce more TF than platelets from matched control subjects.

Relationship between chronic kidney disease and silent cerebral infarction in patients with Type 2 diabetes

AIMS

Silent cerebral infarction (SCI) is an independent risk factor for future symptomatic stroke. Although the prevalence of SCI is closely related to kidney function in non-diabetic individuals, evidence is lacking whether albuminuria and/or reduced estimated glomerular filtration rate (eGFR) independently increase the risk of SCI in diabetic patients. We therefore examined the relationships between albuminuria, eGFR and SCI in patients with Type 2 diabetes mellitus (T2DM).

METHODS

We studied 786 T2DM patients with an eGFR > or = 15 ml/min 1.73/m(2), including 337 women and 449 men [mean (+/- sd), age 65 +/- 11 years]. All patients underwent cranial magnetic resonance imaging (MRI) to detect SCI. GFR was estimated using the modified three-variable equation for Japanese subjects. Albuminuria was defined as a first morning urinary albumin-to-creatinine ratio (ACR) > or = 30 mg/g.

RESULTS

SCI was detected in 415 (52.8%) of the subjects. The prevalence of SCI was significantly associated with both elevated ACR and decreased eGFR in univariate analysis. In multivariate logistic regression analysis, urinary ACR remained independently associated with SCI after adjusting for conventional cardiovascular risk factors [odds ratio (OR) of urinary ACR per logarithmical value: 1.89, 95% confidence interval (CI) = 1.41-2.51, P < 0.001]; however, eGFR was no longer significantly associated with SCI (OR per ml/min 1.73/m(2) = 0.99, 95% CI = 0.98-1.00, P = 0.095).

CONCLUSION

In conclusion, albuminuria but not decreased eGFR may be an independent predictor of prevalent SCI in patients with T2DM.

Comparison of skin microvascular reactivity with hemostatic markers of endothelial dysfunction and damage in type 2 diabetes

Aim:

Patients with non-insulin-dependent diabetes mellitus (NIDDM) are at increased cardiovascular risk due to an accelerated atherosclerotic process. The present study aimed to compare skin microvascular function, pulse wave velocity (PWV), and a variety of hemostatic markers of endothelium injury [von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA), tissue factor pathway inhibitor (TFPI), and the soluble form of thrombomodulin (s-TM)] in patients with NIDDM.

Methods:

54 patients with NIDDM and 38 sex- and age-matched controls were studied. 27 diabetics had no overt micro- and/or macrovascular complications, while the remainder had either or both. The forearm skin blood flow was assessed by laser-Doppler imaging, which allowed the measurement of the response to iontophoretically applied acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation), as well as the reactive hyperemia triggered by the transient occlusion of the circulation.

Results:

Both endothelial and non-endothelial reactivity were significantly blunted in diabetics, regardless of the presence or the absence of vascular complications. Plasma vWF, TFPI and s-TM levels were significantly increased compared with controls only in patients exhibiting vascular complications. Concentrations of t-PA and PAI-1 were significantly increased in the two groups of diabetics versus controls.

Conclusion:

In NIDDM, both endothelium-dependent and -independent microvascular skin reactivity are impaired, whether or not underlying vascular complications exist. It also appears that microvascular endothelial dysfunction is not necessarily associated in NIDDM with increased circulating levels of hemostatic markers of endothelial damage known to reflect a hypercoagulable state.

Insulin inhibits tissue factor expression in monocytes

OBJECTIVES

Platelets from healthy subjects are inhibited by insulin but type 2 diabetes mellitus (T2DM) platelets have become insulin-resistant, which might explain their hyperactivity. In the present study we investigated whether monocytes are responsive to insulin.

METHODS AND RESULTS

LPS-induced tissue factor (TF) upregulation was measured in human monocytes and monocytic THP-1 cells in a factor Xa generation assay. Insulin (0.1-100 nmol L(-1)) induced a dose-dependent inhibition in both cell types and in monocytes 100 nmol L(-1) insulin inhibited cytosolic, membrane-bound and microparticle TF by 32 +/- 2, 27 +/- 3 and 52 +/- 4% (n = 3). Insulin induced Tyr phosphorylation of the insulin receptor (INS-R) and formation of an INS-R - G(i)alpha(2) complex, suggesting interference with LPS-induced cAMP control. Indeed, insulin interfered with LPS-induced cAMP decrease and TF upregulation in a manner similar to an inhibitor of G(i) (pertussis toxin) and agents that raise cAMP (iloprost, forskolin, IBMX) reduced TF upregulation. Although LPS failed to raise cytosolic Ca(2+), quenching of Ca(2+) increases (BAPTA-AM) reduced and induction of Ca(2+) entry (ionophore, P2X7 activation) enhanced upregulation of TF mRNA and procoagulant activity. Insulin interfered with MCP-1-induced Ca(2+) mobilization but not with ATP-induced Ca(2+) rises.

CONCLUSIONS

Insulin inhibits TF expression in monocytes and monocyte-derived microparticles through interference with G(i)alpha(2)-mediated cAMP suppression, which attenuates Ca(2+)-mediated TF synthesis.

High levels of plasma malondialdehyde, protein carbonyl, and fibrinogen have prognostic potential to predict poor outcomes in patients with diabetic foot wounds: a preliminary communication

Diabetic foot ulcer (DFU) is the leading cause of lower extremity amputation and is generally known to have poor prognosis. Oxidative stress is considered important in the pathogenesis of chronic wounds. Fibrinogen is a recognized marker in peripheral vascular disease; increasing levels predict an increased mortality and risk of amputation. The aim of this study was to evaluate if plasma malondialdehyde (MDA), protein carbonyl (PC) and fibrinogen levels can be used as prognostic markers in patients with DFU. The study design was prospective, nonrandomized, and controlled. A total of 41 DFU grade 1 and 20 DFU grade 2 patients were studied in this case-control study. Diabetic controls without foot ulcers and healthy controls were also studied. Plasma MDA, PC, and fibrinogen levels were significantly higher in patients with DFU compared with those without ulcers (P < .05) and nondiabetic controls (P < .001). These parameters increased in association with DFU grade (P < .01). Increased levels of plasma fibrinogen, MDA, and PC correlated with worsened outcomes. An augmented oxidative stress and plasma fibrinogen level >300.4 mg% (95% confidence interval, 100% sensitivity, 99.2% specificity) was correlated with a high risk of amputation in DFU.

Microalbuminuria and endothelial dysfunction: emerging targets for primary prevention of end-organ damage

A minor increase in urinary albumin excretion (microalbuminuria) is known to predict adverse renal and cardiovascular events in diabetic and hypertensive patients. Recent intriguing findings show that microalbuminuria is an early and sensitive marker of future cardiovascular events even in healthy subjects. The mechanisms linking microalbuminuria with end-organ damage have not been fully explained yet; however, generalized endothelial dysfunction might play an important role. Prevailing experimental and clinical data suggest that generalized endothelial dysfunction, frequently characterized by decreased nitric oxide bioavailability, actually precedes the development of microalbuminuria. This review summarizes the current knowledge about the intricate relationship between microalbuminuria and endothelial dysfunction. On the basis of the current evidence, we propose that microalbuminuria and endothelial dysfunction are an emerging target for primary prevention strategies in cardiovascular disease. In near future, dietary components improving nitric oxide bioavailability, such as cocoa-derived flavanols may play important role in these preventive strategies.

Maternal diabetes mellitus is associated with altered deposition of fibrin-type fibrinoid at the villous surface in term placentae

Placentae from control and diabetic patients were used to test three null hypothesis: (1) there are no significant group differences in the volumes of villous syncytiotrophoblast compartments or intervillous fibrin-type fibrinoid, (2) perivillous fibrin-type fibrinoid is deposited randomly at the surface of trophoblast, and (3) amounts and deposition patterns of perivillous fibrin-type fibrinoid do not vary between groups. Term placentae were collected from non-diabetic subjects and five groups of diabetic women classified according to duration, severity and insulin dependence. Tissue specimens and sections were obtained by uniform random sampling. Volumes and surface areas of fibrin-type fibrinoid and trophoblast compartments (thin, syncytial knot, syncytial bridge and denuded regions) were estimated stereologically and compared using variance, chi-squared and contingency table analyses. As to null hypothesis (1), no group differences in volumes of trophoblast compartments were found but volumes of intervillous fibrin-type fibrinoid were greater in the non-insulin-dependent diabetic group. As to null hypothesis (2), regardless of group, fibrin-type fibrinoid was deposited preferentially at sites of denudation in every placenta examined. As to null hypothesis (3), villous surface areas occupied by perivillous fibrin-type fibrinoid were greater in type 1 (insulin-dependent) diabetics with complications (diabetic nephropathy or retinopathy). The surfaces of trophoblast occupied by fibrin-type fibrinoid were also notably larger in non-insulin-dependent diabetics and type 1 diabetics with complications. Except for the surface of denudation sites (which also increased in diabetes), there were no differences in the surfaces of trophoblast regions. These results confirm that the haemostatic steady state is perturbed in the diabetic placenta, that perivillous fibrin-type fibrinoid is deposited preferentially at sites of epithelial loss/damage, and that some diabetic groups are affected differentially.

Tissue factor pathway inhibitor (TFPI) release after heparin stimulation is increased in Type 1 diabetic patients with albuminuria

AIMS

To study heparin-stimulated TFPI release in relation to complications in Type 1 diabetic patients.

SUBJECTS AND METHODS

Nineteen uncomplicated Type 1 diabetic patients (group I) were compared with 18 patients with retinopathy (group II), and nine patients with retinopathy and albuminuria (group III). Blood samples were taken before (basal) and till 30 min after 5000 IU of heparin i.v. (post-heparin). TFPI activity was measured chromogenically. Von Willebrand factor, tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) and thrombomodulin were also measured.

RESULTS

Basal TFPI activity was higher in group III (121 +/- 10%) compared with group II (111 +/- 8%) or group I (110 +/- 13%) (P < 0.05), and strongly correlated with albuminuria (r = 0.66, P < 0.05). At all time points after heparin administration, TFPI activity in group III was significantly higher than in group I. TFPI activity was also higher in group III than in group II 5-30 min post-heparin. The increase in post-heparin TFPI activity, measured as the incremental area under the curve, was higher in group III compared with group I (65 +/- 7 vs. 59 +/- 4; P < 0.05). Of the other parameters, only thrombomodulin was higher in group III (44 +/- 24 vs. 26 +/- 7 (group II) and 28 +/- 9 ng/ml (group I); P < 0.01).

CONCLUSIONS

We conclude that basal and post-heparin TFPI activity is increased in albuminuric patients. The increase in heparin-stimulated TFPI release in patients with albuminuria is higher than in patients with retinopathy or without complications. This could be the result of altered endothelial glycosaminoglycan characteristics.

Erythrocytes as targets for gamma-glutamyltranspeptidase initiated pro-oxidant reaction

Gamma-glutamyltranspeptidase (GGT) is a well known cell plasma membrane and serum circulating enzyme. In clinical chemistry, GGT is used as a marker of alcohol consumption and drug uptake. Serum GGT activity varies in hepatobiliary diseases and cancer. This enzyme is involved in glutathione (GSH) metabolism, which is generally associated with antioxidant properties. However, in recent years, findings from our group and from others showed that GGT-catalysed extracellular metabolism of GSH leads, in the presence of iron, to the generation of reactive oxygen species (ROS). It was demonstrated that those highly reactive species oxidise lipids, cell surface protein thiols or activate transcriptional factors such as Nuclear Factor kappaB (NFkappaB). The objective of the present work is to determine whether the red blood cells are targets for plasma GGT-initiated pro-oxidant reaction. The results obtained demonstrate that the GGT/GSH/iron system oxidises isolated erythrocyte membranes. A significant release of haemoglobin and a decrease of erythrocyte deformability are also observed. In addition, in vivo studies showed a relationship between plasma GGT activity and erythrocyte deformability in 20 studied subjects. In conclusion, GGT-mediated ROS production is able to oxidise erythrocytes and thus disturbs their functions.

A preliminary report on the role of yoga asanas on oxidative stress in non-insulin dependent diabetes mellitus

Nineteen subjects of non-insulin dependent diabetes mellitus (NIDDM) between the age group of 30-60 yrs were studied to see the effect of specific yoga asanas on fasting and postprandial blood glucose (FBG, PPG), serum malondialdehyde (MDA) and glycosylated hemoglobin (HbA(1)) in addition to drug treatment and diet control. The duration of diabetes ranged from 1-10 years. Patients with renal, cardiac and proliferative retinal diseases were excluded from the study. The same patients served as their own control. Subjects were called in the morning to the cardio-respiratory laboratory and were given training by a yoga expert. Yoga asanas included Suryanamskar, Tadasan, TriKonasan, Padmasan, Pranayam, Paschimottanasan, Ardhmatsyendrasan, Pavanmukthasan, Sarpasan and Shavasan. The asanas were done every day for 40 days for 30-40 min. FBG, PPG, serum MDA and HbA(1) were estimated before and after 40 days of yoga asanas regimen. Significant reduction was seen in FBG from 220 mg/dl to 162 mg/dl, PPG from 311 mg/dl to 255 mg/dl, MDA from 6 nmol/l to 3 nmol/l and HbA(1), from 8.8% to 6.4%. Subjects felt better and were relieved of their stresses and had an improvement in their day to day performance. The decrease was statistically significant (p<0.0001 for FBG and PPG, p<0.001 for MDA and for HbA(1)).

Hyperfibrinogenemia and metabolic syndrome in type 2 diabetes: a population-based study

BACKGROUND

It has been hypothesized that fibrinogen clusters with several components of the metabolic syndrome, thus increasing its cardiovascular risk. The aims of the present study were to assess in a large population-based cohort of patients with type 2 diabetes (1) variables associated with fibrinogen and (2) the relationship between hyperfibrinogenemia, a number of components of the metabolic syndrome, and coronary heart disease (CHD).

METHODS

We identified a cross-sectional, population-based cohort of 1574 patients with type 2 diabetes using multiple sources of ascertainment. Components of the metabolic syndrome were hypertension (systolic blood pressure > or = 160 mmHg and/or diastolic blood pressure > or = 95 mmHg and/or treatment with antihypertensive drugs), dyslipidemia (tryglicerides >2.82 mmol/l and/or HDL-cholesterol <1.03 mmol/l), hyperuricemia (uric acid >416 micromol/l) and increased albumin excretion rate (AER > or = 20 microg/min).

RESULTS

Fibrinogen increases with age, HbA(1c), smoking, hypertension and a number of components of the metabolic syndrome, even after adjustment for confounders. Prevalence of CHD increases linearly across quartiles of fibrinogen (from 26.1 to 40.6%, p=0.046). However, in logistic regression, after adjustment for both confounders and known risk factors for CHD, the role of fibrinogen is no more significant, whereas ORs for HbA(1c) between 6.8 and 8.8% and >8.8% vs values <6.8% are, respectively, 1.91 (95% CI 1.36-2.69) and 1.56 (1.07-2.27).

CONCLUSIONS

This population-based study shows that fibrinogen increases with age, HbA(1c), smoking, hypertension and a number of components of the metabolic syndrome, independent of major confounders. We also found that poor blood glucose control was associated with CHD.

Microalbuminuria and markers of the atherosclerotic process: the D.E. S.I.R. study

The relationship between microalbuminuria and tissue-type plasminogen activator antigen (tPA-ag) and fibrinogen was evaluated in non-diabetic subjects. Subjects were participants of the D.E.S.I. R. (Data from an Epidemiological Study on the Insulin Resistance syndrome) Study. Analyses were carried out on 2248 women and 2402 men for fibrinogen and on 272 women and 284 men for tPA-ag. Microalbuminuria was defined as urinary albumin concentration greater than 20 mg/l. Men with microalbuminuria had a 6% higher fibrinogen concentration than those without (3.07 g/l (95% confidence interval: 2.99,3.15) vs. 2.89 g/l (2.87,2.91), adjusted for age and smoking). This relationship existed in hypertensive as well as non-hypertensive subjects. The association between microalbuminuria and tPA-ag existed only in hypertensive men, those with microalbuminuria having a 21% higher tPA-ag than those without (4.39 ng/ml (3.70,5.08) vs. 3.63 ng/ml (3.32,3.94), adjusted for age and smoking). Adjustment for other risk markers for cardiovascular disease did not change the results. There was no relationship between microalbuminuria and these haemostatic factors in women. The results of this study suggest that in non-diabetic men, microalbuminuria is associated with fibrinogen, but with tPA-ag only when concomitant with hypertension.

Inflammation and microalbuminuria in nondiabetic and type 2 diabetic subjects: The Insulin Resistance Atherosclerosis Study

BACKGROUND

Microalbuminuria is a risk factor for cardiovascular disease, but the underlying pathomechanisms are still poorly understood. A relationship between C-reactive protein (CRP), a sensitive marker of inflammation, and atherosclerotic disease has been reported recently.

METHODS

We hypothesized that microalbuminuria might be associated with chronic inflammation and investigated the relationship of urinary albumin excretion, as assessed from the albumin-to-creatinine ratio (ACR), in an untimed morning urine specimen, and two inflammatory markers (CRP and fibrinogen) in the large, triethnic population of the Insulin Resistance Atherosclerosis Study (IRAS). After exclusion of subjects with macroalbuminuria, 1481 subjects were studied.

RESULTS

Both inflammatory markers were related to urinary ACR (r = 0.17 for CRP and r = 0.14 for fibrinogen, both P = 0.0001), an association that remained significant after adjustment for demographic variables, diabetic status, smoking, and use of angiotensin-converting enzyme inhibitors (P < 0.01). Mean levels of CRP and fibrinogen were elevated in microalbuminuric (N = 262) versus normoalbuminuric (N = 1219) subjects (5.37 +/- 0.47 vs. 3.80 +/- 0.15 mg/L and 295.7 +/- 4. 0 vs. 278.2 +/- 1.6 mg/dL, both P < 0.0001). The associations were consistent among nondiabetic and type 2 diabetic subjects and among the three ethnic groups of the IRAS (non-Hispanic whites, blacks, Hispanics). In a logistic regression model, fibrinogen was independently associated with microalbuminuria (P = 0.047), along with hypertension, female gender, waist circumference, and fasting blood glucose, while CRP was not independently related to microalbuminuria in this model (P = 0.26).

CONCLUSION

We have shown an association of CRP and fibrinogen with urinary albumin excretion in the microalbuminuric range in type 2 diabetic and nondiabetic individuals. Chronic inflammation therefore emerges as a potential mediator between microalbuminuria and macrovascular disease.

Relationship between lipid peroxidation and plasma fibrinogen in middle-aged men

The relationship between lipid peroxidation (plasma malondialdehyde [MDA] concentration) and plasma fibrinogen level was analyzed in 144 men, aged 53-62 years. MDA was measured colorimetrically and fibrinogen with the thrombin method. Mean plasma MDA concentration was 12.6 (SD 1.2) micromol/L, plasma fibrinogen level 2.91 (0.47) g/L, and body mass index 27.1 (3.5) kg/m(2). Prevalence of smoking was 17%. MDA correlated moderately with fibrinogen. Both MDA and fibrinogen correlated positively with waist hip ratio (WHR) and blood leukocyte count, but inversely with VO(2)max. Both MDA and fibrinogen levels were higher in smokers than in non-smokers (p<0. 01). In multiple stepwise regression analysis, plasma MDA, VO(2)max, smoking, and leukocyte count explained 38.1% of the variance in plasma fibrinogen level, with the individual contributions reaching 20.6%, 9.7%, 5.5%, and 2.3%, respectively. WHR, serum triglycerides, and age did not enter the model. These data suggest that increased lipid peroxidation is associated with elevated plasma fibrinogen level in middle-aged men.

Reactive oxygen species enhances endothelin-1 production of diabetic rat glomeruli in vitro and in vivo

Both reactive oxygen species (ROS) and endothelin-1 (ET- 1) have been implicated in the pathophysiology of diabetic nephropathy. The interrelationship between them, however, has not been documented in this disease. To determine whether ROS regulates ET-1 production in diabetic kidneys, we examined the in vitro and in vivo effects of ROS donors and scavengers on ET-1 production of diabetic rat glomeruli. For in vitro study, the glomeruli were isolated with a sieving method from streptozotocin-induced diabetic rats and killed at 1 week, 1 month, and 3 months, respectively. Superoxide was measured by a spectrophotometer, and ET-1 was measured by radioimmunoassay. The results demonstrated that the basal production levels of superoxide and ET-1 were higher in diabetic glomeruli than in normal glomeruli in vitro. There was a positive correlation between the production of superoxide and ET-1 in diabetic glomeruli. The basal ET-1 production was markedly attenuated by ROS scavengers including superoxide dismutase, catalase, dimethyl sulfoxide, and deferoxamine in diabetic glomeruli. Exogenous ROS generated by xanthine/xanthine oxidase significantly enhanced ET-1 generation by both diabetic and normal glomeruli. A high glucose concentration (500 mg/dL) in vitro increased ET-1 production by normal glomeruli but not diabetic glomeruli, and insulin partly suppressed ET- 1 production by diabetic glomeruli. The in vivo study demonstrated that when diabetic rats were injected daily with superoxide dismutase or catalase after diabetes was induced, the basal production of ET-1 was markedly attenuated after 1 week and 1 month, respectively. These results indicate that exogenously or endogenously derived ROS can enhance ET-1 production by diabetic rat glomeruli and that ROS scavengers suppress ET- 1 production both in vitro and in vivo. The effects of ROS on ET-1 production of diabetic glomeruli may be partly caused by the effect of hyperglycemia or insulin deficiency.

Early endothelial alterations in non-insulin-dependent diabetes mellitus

The high incidence of cardiovascular morbidity and mortality in non-insulin-dependent diabetes mellitus with albuminuria cannot be fully explained by the presence of standard cardiovascular risk factors. We assessed some pathogenic factors of diabetic vascular atherosclerotic damage in 72 non-insulin-dependent diabetes mellitus patients controlled by diet alone and 60 healthy controls. Our study aim was to assess the early onset of these alterations and to correlate them with the presence of microalbuminuria. We determined their incidence in two carefully selected groups of diabetic patients without clinical signs of cardiovascular risk and complications, where diet alone achieved glycometabolic balance. Microalbuminuric patients had an alterated oxide-reductive balance and elevated values of plasminogen activator inhibitor, tissue plasminogen activator, von Willebrand factor, endothelin-1 and betathromboglobulin compared with the normoalbuminuric diabetics and controls. Our findings support the hypothesis that a state of endothelial dysfunction characterized by altered oxide-reductive balance, modified hemostasis and changes in the endothelial barrier properties occurs much earlier in non-insulin-dependent diabetic patient especially in diabetics with microalbuminuria. In addition, alterations in the oxide-reductive balance, and hemostasis occur early and may be an underlying cause of microangiopathic complications in microalbuminuric diabetics.

Nephropathy and hypertension in diabetes

The treatment of the patient with diabetes, with or without hypertension, is complex and challenging. Hyperglycemic treatment should ideally not only control blood glucose, but also prevent the chronic complications and associated metabolic derangements that can lead to increased morbidity and mortality. Hypertensive treatment should not only decrease blood pressure, but also reduce the risk of macrovascular and microvascular disease. The use of antihypertensive agents that improve insulin resistance, dyslipidemia, glycemic control, and nephropathy is preferred whenever possible. The real key to success in the care of the hypertensive diabetic patient is adequate screening and appropriate, early treatment. Currently, there is ample evidence to support the use of intensive management with the goal of near-normalization of blood glucose levels in most patients with diabetes. Similarly, aggressive treatment of hypertension is the current standard. Accomplishing these goals helps to prevent the development of chronic diabetic complications, including nephropathy. ESRD need not be the inevitable outcome for individuals with early diabetic nephropathy. Interventions currently available that are targeted at the known modifiable risk factors underlying the development and progression of diabetic nephropathy offer the best hope for reducing the incidence and severity of this complication. Prevention of the complications of diabetes, including nephropathy, must be the goal for the future on behalf of all those who now have diabetes.

Detection of anti-myeloperoxidase antibodies in the serum of patients with type 1 diabetes mellitus

Anti-myeloperoxidase (anti-MPO) antibodies were detected in 34 of 88 (38%) patients with type 1 diabetes mellitus but in only 3 of 55 (5.7%) healthy subjects and in 4 of 20 patients with autoimmune disease. Specificity of anti-MPO antibodies was assessed by MPO inhibition studies. No relationship was found between the occurrence of anti-MPO and anti-thyroperoxidase antibodies. Levels of soluble intercellular adhesion molecule 1 (ICAM-1) were found to be higher in anti-MPO antibody-positive (n = 28, 508 +/- 126 ng/ml) than in anti-MPO antibody-negative (n = 58, 438 +/- 140 ng/ml: P < 0.05) patients. A state of chronic neutrophil activation has been described in diabetes mellitus. As anti-MPO antibodies can stimulate neutrophils to damage endothelial cells in systemic vasculitis, this suggests that a similar mechanism may be operative in the development of diabetic angiopathy.

Treatment of symptomatic diabetic peripheral neuropathy with the anti-oxidant alpha-lipoic acid. A 3-week multicentre randomized controlled trial (ALADIN Study)

Anti-oxidant treatment has been shown to prevent nerve dysfunction in experimental diabetes mellitus, thus providing a rationale of potential therapeutic value for diabetic patients. The effects of the anti-oxidant alpha-lipoic acid (thioctic acid) were studied in a 3-week multicentre, randomized, double-blind placebo-controlled trial (Alpha-Lipoic Acid in Diabetic Neuropathy; ALADIN) in 328 non-insulin-dependent diabetic patients with symptomatic peripheral neuropathy who were randomly assigned to treatment with intravenous infusion of alpha-lipoic acid using three doses (1200, 600, or 100 mg ALA) or placebo (PLAC). Neuropathic symptoms (pain, burning, paraesthesiae, and numbness) were scored at baseline and at each visit (days 2-5, 8-12, and 15-19) prior to infusion. In addition, the Hamburg Pain Adjective List, a multidimensional specific pain questionnaire, and the Neuropathy Symptom and Disability Scores were assessed at baseline and day 19. According to the protocol 260 (65/63/66/66) patients completed the study. The total symptom score in the feet decreased from baseline to day 19 by -4.5 +/- 3.7 (-58.6%) points (mean +/- SD) in ALA 1200, -5.0 +/- 4.1 (-63.5%) points in ALA 600, -3.3 +/- 2.8 (-43.2%) points in ALA 100, and -2.6 +/- 3.2 (-38.4%) points in PLAC (ALA 1200 vs PLAC: p = 0.003; ALA 600 vs PLAC: p < 0.001). The response rates after 19 days, defined as an improvement in the total symptom score of at least 30%, were 70.8% in ALA 1200, 82.5% in ALA 600, 65.2% in ALA 100, and 57.6% in PLAC (ALA 600 vs PLAC; p = 0.002). The total scale of the Pain Adjective List was significantly reduced in ALA 1200 and ALA 600 as compared with PLAC after 19 days (both p < 0.01). The rates of adverse events were 32.6% in ALA 1200, 18.2% in ALA 600, 13.6% in ALA 100, and 20.7% in PLAC. These findings substantiate that intravenous treatment with alpha-lipoic acid using a dose of 600 mg/day over 3 weeks is superior to placebo in reducing symptoms of diabetic peripheral neuropathy, without causing significant adverse reactions.

No evidence for systemic oxidant stress in Parkinson's or Alzheimer's disease

Oxidant stress secondary to dopamine metabolism has been proposed as a pathogenic factor in the development of Parkinson's disease. Biochemical abnormalities extending beyond the central nervous system have been identified in patients with this condition. Previous investigators have found abnormally elevated concentrations of the lipid peroxidation product, malondialdehyde, in the plasma and serum of patients with Parkinson's disease. We attempted to replicate these findings but controlled for other factors that could influence malondialdehyde levels. We detected no significant elevations in mean serum malondialdehyde concentrations in either levodopa-treated or untreated patients with Parkinson's disease, compared to normal controls; similarly, no elevation was found in a group of patients with dementia of Alzheimer's type. On the other hand, a group of subjects with diabetes mellitus but no neurodegenerative disease had significantly elevated mean serum malondialdehyde levels, consistent with previous studies of diabetic patients. Autoxidation is one of the two major routes by which dopamine and dopa metabolism may generate oxygen free radicals. We analyzed the autoxidation product of dopa, 5-S-cysteinyl-dopa, in the plasma of these same groups of patients with neurodegenerative disease and normal controls; no significant differences were identified. Serum concentrations of two other antioxidant substances, alpha-tocopherol and uric acid, were also statistically similar in these groups. In conclusion, analysis of several blood products relevant to oxidant stress, including malondialdehyde, 5-S-cysteinyl-dopa, alpha-tocopherol, and uric acid, failed to distinguish patients with Parkinson's disease or dementia of Alzheimer's type from controls.

Plasma and urine malondialdehyde levels in non-insulin-dependent diabetic patients with and without microalbuminuria

Malondialdehyde, a marker of lipid peroxidation, was measured as thiobarbituric acid-reactive substance in 78 non-insulin-dependent diabetic patients and 28 healthy subjects. Patients were divided into groups and subgroups according to the presence of microalbuminuria and other complications. Plasma and urine malondialdehyde concentrations were significantly higher in patients with and without microalbuminuria than in controls. In contrast to urine malondialdehyde, plasma malondialdehyde levels were significantly higher in microalbuminuric diabetes than in the normolbuminuric diabetic group. There was no correlation between malondialdehyde concentration and glycemic control. This study confirmed the existence of lipid peroxidation disorders in diabetic patients.

Hematologic complications of diabetes mellitus

In summary, hematologic abnormalities in diabetes affect the function, morphology, and metabolism of blood cells, and the coagulation system. These complications can contribute to the development of anemia, infection, and hypercoagulability in diabetic dogs and cats. Some hematologic changes, such as glycosylated hemoglobin and fructosamine, play an important role as markers of glycemic control. Hematologic changes also serve as important models for changes occurring in other tissues, such as cataract formation and nephropathy. Further study of blood alterations will enhance our knowledge of the biochemistry and pathophysiology of diabetes and diabetic complications and stimulate the development of effective preventative and therapeutic measures.

Cigarette smoking and free radical activity in young adults with insulin-dependent diabetes

Cigarette smoke is potentially capable of generating a high free radical load in the body and many patients with diabetes are smokers. This study was designed to investigate the relationship between long-term smoking and free radical activity in young adult insulin-dependent diabetic patients with no evidence of macrovascular disease. Eight-five patients (48 male) aged 17-40 years were studied. Mean duration of diabetes was 10.5 years (0.08-33) and 39 were cigarette smokers. All had normal serum creatinine levels. The free radical markers measured were: thiobarbituric acid reactive substances, glutathione peroxidase, and superoxide dismutase. No significant differences in thiobarbituric acid reactive substances, glutathione peroxidase, or superoxide dismutase, were found between the diabetic smokers and non-smokers. Also no difference was found comparing the diabetic patients with 40 non-diabetic control subjects (20 smokers). Persistent albuminuria was present in 16 patients (10 microalbuminuria) and free radical marker concentrations in these subjects were similar to the normoalbuminuric patients. This data suggests that any increase in free radical activity due to cigarette smoke is adequately scavenged in young adults with diabetes who are free of significant macrovascular disease.

Alteration of oxide reductive and haemostatic factors in type 2 diabetics

OBJECTIVE

To assess any pathogenic role of radical activity and haemostatic alteration in the early cardiovascular disease of microalbuminuric type 2 diabetics (non-insulin dependent).

DESIGN

A selected cohort of type 2 diabetics was identified, divided according to urinary albumin excretion and compared with a healthy control group depending on some haemostatic factors and radical activity.

SETTING

All the subjects were studied as outpatients.

SUBJECTS

Eighty diabetics and 84 healthy controls were interviewed and underwent blood tests to exclude standard cardiovascular risk factors before follow up.

MAIN OUTCOME MEASURES

The subjects were males, age range 43-55 years, and divided according to albumin excretion (microalbuminuria > 30-200 mg L-1; normoalbuminuria < 15 mg L-1). The mean duration of diabetes referred by the patients was 9.3 years in albuminuric and 11.1 years in normoalbuminuric patients with a good control of plasma glucose level. Neither the diabetics nor the control group showed clinical evidence of renal and cardiovascular diseases.

RESULTS

Microalbuminuric patients presented elevated malondialdehyde concentration, glutathione peroxidase activity, phospholipidic fatty acid levels, fibrinogen, plasminogen activator inhibitor, tissue plasminogen activator and von Willebrand factor compared with normoalbuminuric patients and controls. More collagen was required in microalbuminuric diabetics than in normoalbuminurics and controls.

CONCLUSIONS

Our results confirm that both free radical activity and changes in haemostatic factors can be observed in type 2 diabetes and particularly in patients with albuminuria. Our very selected series with short duration, good control of diabetes and lack of clinical evidence of cardiovascular disease may suggest that these abnormalities develop earlier and may be associated with, and/or implicated in, the pathogenesis of microvascular complications which can be related to a higher and early cardiovascular morbidity and mortality rate in microalbuminuric diabetics.

Coagulation activation in diabetes mellitus: the role of hyperglycaemia and therapeutic prospects

Numerous studies have shown that coagulation abnormalities occur in the course of diabetes mellitus, resulting in a state of thrombophilia. These observations are supported by epidemiological studies which demonstrate that thromboembolic events are more likely to occur in diabetic patients. The coagulation abnormalities observed in diabetic patients seem to be caused by the hyperglycaemia, which also constitutes the distinguishing feature of this disease. These data are also supported by in vitro studies which demonstrate how glucose can directly determine alterations in the coagulation system. The abnormalities observed involve all stages of coagulation, affecting both thrombus formation and its inhibition, fibrinolysis, platelet and endothelial function. The final result is an imbalance between thrombus formation and dissolution, favouring the former. Hyperglycaemia probably determines the onset of these abnormalities through three mechanisms which are, respectively, non-enzymatic glycation, the development of increased oxidative stress and a decrease in the levels of heparan sulphate. The first seems to affect the functionality of key molecules of coagulation in a negative sense. Oxidative stress constitutes an important pro-thrombotic stimulus, while the decrease in heparan sulphate determines a reduction in antithrombotic defenses. Good metabolic control could play a key role in controlling the coagulation irregularities in diabetes. However, considering the difficulties in achieving such an objective, it is possible that the use of drugs may represent a valid alternative. In fact, several drugs exist which are of potential interest. It is, however, necessary to perform long-term studies which demonstrate unequivocably that by controlling the coagulation abnormalities in diabetic patients, prolongation of life is possible.

Thrombogenic factors are related to urinary albumin excretion rate in type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetic patients

Parameters of haemostasis, endothelial cell markers and lipid peroxide levels were studied in 64 Type 1 (insulin-dependent) and 94 Type 2 (non-insulin-dependent) diabetic patients according to their urinary albumin excretion rate in comparison with age-matched control subjects. We determined plasma levels of fibrinogen (Clauss' method), coagulation factor VII:activity (clotting assay), factor VII antigen, protein C and S antigen, von Willebrand factor antigen, D-dimer concentration (ELISA), and lipid peroxide levels (thiobarbituric acid) in relation to urinary albumin excretion rate (RIA). Significant positive correlations were found between urinary albumin excretion rate and plasma fibrinogen (p < 0.005, p < 0.02), factor VII activity (p < 0.0002, p < 0.002), factor VII antigen (p < 0.0001, p < 0.001), protein C (p < 0.003, p < 0.05), and lipid peroxides (p < 0.02, p < 0.004) in Type 1 as well as in Type 2 diabetes. Von Willebrand factor (p < 0.001) and protein S (p < 0.0005) correlated with albuminuria only in patients with Type 1 diabetes. Although most of the haemostatic abnormalities are already found in normoalbuminuric patients, the significant positive correlations to urinary albumin excretion indicate that endothelial cell damage and coagulation disorders deteriorate with the progression of diabetic nephropathy.