Correlation of various serum biomarkers with the severity of diabetic retinopathy

Hyperglycemia induced inflammation and angiogenic factors are implicated as a contributor to the onset and progression of diabetic retinopathy (DR) in type 2 diabetes mellitus patients (T2DM). Tumor necrosis factor (TNF-alpha) and C-reactive protein (CRP) are inflammatory cytokines which induce retinal VEGF and are involved in the progression of proliferative diabetic retinopathy (PDR). Therefore the aim of the present study is to investigate the relationship between diabetic retinopathy and systemic inflammation in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Patients with T2DM, with or without diabetic retinopathy were included in the study. Serum inflammatory cytokines, vascular growth factor were studied in different stages of DR.

RESULTS

Patients with T2DM with and without diabetic retinopathy were compared. Patients with diabetic retinopathy had increased serum levels of inflammatory cytokines CRP, TNF-alpha, as well as VEGF compared to serum levels of diabetic patients without retinopathy.

CONCLUSION

T2DM patients with retinopathy have higher levels of circulating inflammatory cytokines and VEGF compared to patients without retinopathy. These proinflammatory cytokines and angiogenic factors are involved in the progression of DR and proliferative diabetic retinopathy. The results showed the importance of inflammation and vascular endothelial growth factor in the progression of NPDR and PDR.

Review: Endothelial dysfunction and pre-symptomatic atherosclerosis in type 1 diabetes — pathogenesis and identification

The vascular endothelium offers an attractive model for detecting functional abnormalities prior to structural changes in the vasculature. Demonstration of progression from endothelial dysfunction through to atherosclerosis is required. Measurements of forearm bloodflow, biochemical markers and biophysical assessments of the endothelium have been employed as research tools for investigating pre-symptomatic atherosclerosis.

However, studies examining endothelial function in type 1 diabetes have been sparse and conflicting. Differences in methodology and the study populations were potential confounding factors. Augmented vasodilatory prostanoids compensate for reduced nitric oxide bioavailability in determining endothelial function in type 1 diabetes. Hyperglycaemia appears to be the initiating event in type 1 diabetes which promotes a variety of biochemical events which are pathogenic to the endothelium.

Improved understanding of the endothelium may facilitate the development of novel diagnostic tools and interventions targeting the accelerated atherosclerosis associated with type 1 diabetes.

Folate therapy improves the stress-to-rest mean LV volume ratio in myocardial perfusion imaging in patients with diabetes

OBJECTIVE

Patients with diabetes have higher stress-to-rest mean left ventricular volume (SRLVV) ratio in myocardial perfusion imaging (MPI) and hyperhomocysteinemia. We studied the effect of folate therapy on SRLVV ratio and plasma homocysteine levels in patients with diabetes.

METHODS

Forty patients were enrolled and thirty-two completed the study. The patients underwent a 2-day pharmacological stress test and rest MPI before and 2 months after treatment with either 5 mg folic acid or placebo. SRLVV ratios were calculated, and plasma homocysteine levels were measured, before and after treatment.

RESULTS

Among the 32 patients who completed the study, 15 received folic acid and 17 received placebo. The age of subjects (folate 51.5 ± 6.1 years; placebo 50.6 ± 8.1 years), male/female ratio (folate 6/11; placebo 9/6),or MPI findings (proportion of normal results: folate 80.0 %; placebo 94.1 %) were similar between the two groups. The baseline SRLVV ratio was similar between groups (folate: 1.00 ± 0.09 vs. placebo: 0.97 ± 0.13); however, the post-treatment SRLVV ratio was significantly lower (P < 0.001) in the folate group than in the placebo group (folate: 0.93 ± 0.10 vs. placebo: 1.04 ± 0.17). A general linear repeated-measures model showed a significant difference in the change in SRLVV ratio between participants receiving folate and those receiving placebo. Post-treatment homocysteine level was lower after folate treatment (from 14.5 ± 4.6 to 11.5 ± 5.3 µmol/L), as compared to placebo (from 13.7 ± 5.0 to 17.9 ± 4.5 µmol/L) (P = 0.01). The changes in SRLVV ratio and homocysteine level were correlated (r = 0.45; P = 0.016).

CONCLUSIONS

Short-term folate therapy reduced SRLVV ratio and plasma homocysteine level.

Synthesis and evaluation of multi-functional NO-donor/insulin-secretagogue derivatives for the treatment of type II diabetes and its cardiovascular complications

Although there is a significant effort in the discovery of effective therapies to contrast both the pathological endocrine and metabolic aspects of diabetes and the endothelial dysfunction associated with this disease, no hypoglycemic drug has been proven to defeat the cardiovascular complications associated with type II diabetes. The aim of this research was to design new compounds exhibiting a double profile of hypoglycemic agents/NO-donors. The synthesis of molecules obtained by the conjunction of NO-donor moieties with two oral insulin-secretagogue drugs (repaglinide and nateglinide) was reported. NO-mediated vasorelaxing effects of the synthesized compounds were evaluated by functional tests on isolated endothelium-denuded rat aortic rings. The most potent molecule (4) was tested to evaluate the hypoglycemic and the anti-ischemic cardioprotective activities. This study indicates that 4 should represent a new insulin-secretagogue/NO-donor prodrug with an enhanced cardiovascular activity, which may contrast the pathological aspects of diabetes and endowed of cardioprotective activity.

Oral Lactobacillus reuteri GMN-32 treatment reduces blood glucose concentrations and promotes cardiac function in rats with streptozotocin-induced diabetes mellitus

Impaired regulation of blood glucose levels in diabetes mellitus (DM) patients and the associated elevation of blood glucose levels are known to increase the risk of diabetic cardiomyopathy (DC). In the present study, a probiotic bacterium, Lactobacillus reuteri GMN-32, was evaluated for its potential to reduce blood glucose levels and to provide protection against DC risks in streptozotocin (STZ)-induced DM rats. The blood glucose levels of the STZ-induced DM rats when treated with L. reuteri GMN-32 decreased from 4480 to 3620 mg/l (with 10⁷ colony-forming units (cfu)/d) and 3040 mg/l (with 10⁹ cfu/d). Probiotic treatment also reduced the changes in the heart caused by the effects of DM. Furthermore, the Fas/Fas-associated protein with death domain pathway-induced caspase 8-mediated apoptosis that was observed in the cardiomyocytes of the STZ-induced DM rats was also found to be controlled in the probiotic-treated rats. The results highlight that L. reuteri GMN-32 treatment reduces blood glucose levels, inhibits caspase 8-mediated apoptosis and promotes cardiac function in DM rats as observed from their ejection fraction and fractional shortening values. In conclusion, the administration of L. reuteri GMN-32 probiotics can regulate blood glucose levels, protect cardiomyocytes and prevent DC in DM rats.

Diabetes-associated macrovasculopathy: pathophysiology and pathogenesis

The complications associated with diabetic vasculopathy are commonly grouped into two categories: microvascular and macrovascular complications. In diabetes, macrovascular disease is the commonest cause of mortality and morbidity and is responsible for high incidence of vascular diseases such as stroke, myocardial infarction and peripheral vascular diseases. Macrovascular diseases are traditionally thought of as due to underlying obstructive atherosclerotic diseases affecting major arteries. Pathological changes of major blood vessels leading to functional and structural abnormalities in diabetic vessels include endothelial dysfunction, reduced vascular compliance and atherosclerosis. Besides, advanced glycation end product formation interacts with specific receptors that lead to overexpression of a range of cytokines. Haemodynamic pathways are activated in diabetes and are possibly amplified by concomitant systemic hypertension. Apart from these, hyperglycaemia, non-enzymatic glycosylation, lipid modulation, alteration of vasculature and growth factors activation contribute to development of diabetic vasculopathy. This review focuses on pathophysiology and pathogenesis of diabetes-associated macrovasculopathy.

Flow mediated dilatation and carotid intimal media thickness in South Indian type 2 diabetic subjects

OBJECTIVE

The aims of this study were to determine: (1). endothelial function in type 2 diabetic subjects with and without diabetic microvascular complications using flow mediated dilatation method (FMD); (2). influence of other variables on FMD; and (3). the correlation between FMD and carotid intimal media thickness (IMT).

RESEARCH, DESIGN AND METHODS

In this cross-sectional study, flow mediated dilatation (FMD) and intimal media thickness (IMT) were determined using high resolution ultrasonography in 20 non-diabetic subjects, in 23 type 2 diabetic subjects without any complications and in 23 type 2 diabetic patients with nephropathy and retinopathy.

RESULTS

Age-adjusted mean (S.D.) FMD value in diabetic subjects (8.9 +/- 5%) was lower (P < 0.0001) when compared with the group of control subjects (18.8 +/- 7.5 %. However, there was no difference in the age-adjusted FMD values between diabetic subjects with and without complications (7.3 +/- 3.3 % versus 10.5 +/- 5.9 %). FMD levels did not vary significantly between sexes in both non-diabetic and diabetic groups. FMD correlated negatively with carotid IMT (r = -0.23, P < 0.05). In multiple linear regression analysis, age adjusted FMD was associated only with type 2 diabetes with complications (P = 0.012). The variance explained was 21.9%.

CONCLUSION

Abnormal FMD and increased carotid IMT were present in type 2 diabetes. Both these parameters negatively correlated with each other supporting an association between impaired FMD and atherogenesis. As these abnormalities existed even in diabetic subjects with no microvascular complications, it is likely that they preceded the development of these complications.

Endothelial dysfunction in patients with type 2 diabetes and the effects of thiazolidinedione antidiabetic agents

Endothelial dysfunction is increasingly recognised as a key event in the pathogenesis of atherosclerosis, which occurs in association with insulin resistance early in the course of type 2 diabetes mellitus (T2DM). Thiazolidinediones (TZDs), such as rosiglitazone, are a class of oral antidiabetic agents that act primarily as insulin sensitisers, reducing insulin resistance with associated improvements in glycemic control. Available data indicate that thiozolidinediones also have beneficial effects on numerous markers of endothelial function and profound antiinflammatory activity, indicative of potential antiatherogenic activity. These effects may be of considerable clinical significance if sustained during long-term therapy, given the morbidity and mortality associated with atherosclerosis in T2DM patients.