A possible involvement of crosstalk between advanced glycation end products (AGEs) and asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor in accelerated atherosclerosis in diabetes

The effect of metformin on indomethacin-induced gastric ulcer: Involvement of nitric oxide/Rho kinase pathway

Gastric ulcer is a very common disease that represent an economic burden. Non-steroidal anti-inflammatory drugs induce ulcer in old patients and in patients with comorbidities. Indomethacin is widely used to induce gastric ulcer in animal models. Diabetic patients are highly susceptible to develop gastric ulcer. Metformin, the first line medication for the treatment of type II diabetes melilites that have many off label uses in non-diabetic patients, has been recently reported to have anti-inflammatory activities. Therefore, this research was conducted to assess the possible healing effects of metformin on gastric ulcers induced by indomethacin in rats. Indomethacin (48 mg/kg) single dose increased stomach acidity, ulcer index and induced histopathological changes. Indomethacin also decreased mucin levels and increased the activity of tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), Rho-associated protein kinas-1 (ROCK-1) and decreased the levels of the protective nitric oxide (NO). After the induction of ulcer, rats were treated by omeprazole (30 mg/kg) or metformin (50, 100 or 200 mg/kg). Omeprazole and metformin were found to decrease stomach acidity and ulcer index, restored the histological features and increased mucin levels. Both also decreased the levels of NF-κB, TNF-α, ROCK-1 and increased NO. Metformin exerted ulcer healing effects comparable to that of omeprazole. This can be attributed, at least partly, to its anti-inflammatory activity and increasing NO levels.

Glycated peptides are associated with the variability of endothelial dysfunction in the cerebral vessels and the kidney in type 2 diabetes mellitus patients: a cross-sectional study

BACKGROUND

Diabetic atherosclerosis and microangiopathy parallel diabetic nephropathy. The aim of our study was to evaluate the pattern of endothelial dysfunction in two vascular territories, the kidney and the brain, both affected by diabetic vasculopathic complications. The endothelial variability was evaluated in relation to advanced glycation end-products modified peptides.

METHODS

Seventy patients with type 2 diabetes mellitus and 11 healthy subjects were assessed concerning urine albumin: creatinine ratio, plasma and urinary advanced glycation end-products, plasma asymmetric dimethyl-arginine, serum cystatin C, intima-media thickness in the common carotid arteries, the pulsatility index, the resistance index in the internal carotid arteries and the middle cerebral arteries, the cerebrovascular reactivity through the breath-holding test.

RESULTS

The breath-holding index correlated with asymmetric dimethyl-arginine (R²=0.151; p<0.001), plasma advanced glycation end-products (R²=0.173; p<0.001), C-reactive protein (R²=0.587; p<0.001), duration of diabetes mellitus (R²=0.146; p=0.001), cystatin C (R²=0.220; p<0.001), estimated glomerular filtration rate (R²=0.237; p=0.001). Urine albumin: creatinine ratio correlated with urinary advanced glycation end-products (R²=0.257; p<0.001), but not with asymmetric dimethyl-arginine (R²=0.029; p=0.147).

CONCLUSIONS

In type 2 diabetic patients endothelial dysfunction in the cerebral vessels appears to be dissociated from glomerular endothelial dysfunction in early diabetic nephropathy. Advanced glycation end-products could impact both the cerebral vessels and the glomerular endothelium.

Alcohol consumption and the risk of coronary heart disease in postmenopausal women with diabetes: Women's Health Initiative Observational Study

BACKGROUND

Although several observational studies have consistently reported an inverse association between moderate alcohol consumption and risk of coronary heart disease (CHD), it is yet not well established if this association also exists among people with type 2 diabetes. The aim of this study is to evaluate the association between the frequency and quantity of alcohol intake and the risk of developing CHD among postmenopausal women with diabetes.

METHODS

We conducted a prospective cohort study, which included 3,198 women with self-reported diabetes and without any history of cardiovascular disease at baseline, in the Women's Health Initiative Observational Study. Alcohol intake was assessed by a semiquantitative food frequency questionnaire. The primary outcome of this study was CHD, which was validated by medical record review. Cox proportional hazards regression was used to estimate the hazard ratio (HR) for the association of alcohol intake and risk of incident CHD while adjusting for several potential confounders.

RESULTS

During the 22,546 person-years of follow-up, there were 336 incident cases of CHD. Both frequency and quantity of alcohol intake were inversely associated with the risk of developing CHD. Compared to nondrinkers, the multivariable HRs across categories of frequency of alcohol consumption (<or=0.5, 0.5-2 and >or=2 drinks/week) were 0.89 (95% confidence intervals [CI]: 0.63, 1.26), 0.84 (95% CI: 0.56, 1.25) and 0.65 (95% CI: 0.43, 0.99), respectively (p for trend: 0.04). This association did not appear to differ based on the type of the alcoholic beverage consumed.

CONCLUSIONS

Moderate alcohol consumption of postmenopausal women with type 2 diabetes may have a benefit on CHD similar to that seen in postmenopausal nondiabetic women. The potential risks of alcohol on noncardiac outcomes may need consideration when recommending alcohol to women with diabetes.

Gastroprotective effects of the insulin sensitizers rosiglitazone and metformin against indomethacin-induced gastric ulcers in Type 2 diabetic rats

1. Gastric ulcers are common in Type 2 diabetic patients. Of all drugs used in the treatment of Type 2 diabetes, the insulin sensitizers thiazolidinediones (e.g. rosiglitazone) and metformin exhibit additional effects in ameliorating oxidative stress and inflammation, rendering them attractive candidates for the prevention of gastric ulcer in Type 2 diabetes. Thus, the aim of the present study was to evaluate the gastroprotective effects of rosiglitazone and metformin against indomethacin-induced gastric ulcer in Type 2 diabetic and non-diabetic rats. 2. Diabetes was induced by a single injection of streptozotocin (60 mg/kg, i.p., dissolved in 0.1 mol/L cold citrate buffer, pH 4.5), 15 min after administration of 120 mg/kg, i.p., nicotinamide. Three weeks after the successful induction of diabetes, rats were subjected to pyloric ligation and then injected immediately with 30 mg/kg, i.p., indomethacin. Three hours after indomethacin administration, rats were killed and gastric injury was evaluated. Ranitidine (50 mg/kg) was used as a reference drug and was administered in a single oral dose 1 h before indomethacin injection, as were rosiglitazone (3 mg/kg) and metformin (500 mg/kg). 3. Both rosiglitazone and metformin exhibited gastroprotective effects, as evidenced by significant decreases in the ulcer index, free and total acid output in gastric juice and gastric mucosal malondialdehyde concentrations, with concomitant increases in gastric juice pH (only with rosiglitazone), mucin concentrations, gastric mucosal concentrations of nitric oxide and catalase activity compared with untreated diabetic rats. Conversely, rosiglitazone and metformin had no effect on peptic activity and gastric mucosal prostaglandin E(2) content, particularly in the diabetic group, compared with the untreated groups. 4. In conclusion, rosiglitazone and metformin protect Type 2 diabetic rats against indomethacin-induced gastric ulceration, most possibly via antisecretory actions, enhanced mucosal protection and anti-oxidant activity. Rosiglitazone seems to be provide superior gastroprotection to metformin.