Maria Pioruńska-Stolzmann

Role of epigenetic mechanisms in the development of chronic complications of diabetes

There is growing evidence that epigenetic regulation of gene expression including post-translational histone modifications (PTHMs), DNA methylation and microRNA (miRNA)-regulation of mRNA translation could play a crucial role in the development of chronic, diabetic complications. Hyperglycemia can induce an abnormal action of PTHMs and DNA methyltransferases as well as alter the levels of numerous miRNAs in endothelial cells, vascular smooth muscle cells, cardiomyocytes, retina, and renal cells. These epigenetic abnormalities result in changes in the expression of numerous genes contributing to effects such as development of chronic inflammation, impaired clearance of reactive oxygen species (ROS), endothelial cell dysfunction and/or the accumulation of extracellular matrix in the kidney, which causing the development of retinopathy, nephropathy or cardiomyopathy. Some epigenetic modifications, for example PTHMs and DNA methylation, become irreversible over time. Therefore, these processes have gained much attention in explaining the long-lasting detrimental consequences of hyperglycaemia causing the development of chronic complications even after improved glycaemic control is achieved. Our review suggests that the treatment of chronic complications should focus on erasing metabolic memory by targeting chromatin modification enzymes and by restoring miRNA levels.

Relation of salivary antioxidant status and cytokine levels to clinical parameters of oral health in pregnant women with diabetes.

OBJECTIVE Both pregnancy and diabetes are thought to predispose to the impairment of oral health. As saliva contributes to oral homeostasis, we have characterised its properties and flow rate in pregnant women with or without diabetes. DESIGN Unstimulated whole mixed saliva was collected from 63 women in the first trimester of pregnancy and analysed for the concentration of selected antioxidants, cytokines, and growth factors. RESULTS Pregnant women with diabetes were found to have markedly increased indexes of caries activity, plaque formation, gingival and periodontal status, as well as increased salivary antioxidant capacity and pro-inflammatory cytokine levels. These changes were more pronounced in patients with long-term disease and systemic diabetic complications, but only partly correlated with the level of blood glycated haemoglobin. Of the cytokines examined, salivary VEGF and HGF concentrations in diabetic pregnant women correlated in a positive and negative manner, respectively, with the prevalence of caries. Moreover, VEGF levels in this group correlated inversely with the probing depth and clinical attachment levels. All such associations did not occur in healthy individuals. In contrast, the salivary pH and flow rate correlated inversely with several parameters of caries and plaque formation irrespectively of whether the pregnant women were diabetic or not. CONCLUSIONS Diabetes in pregnant women significantly changes saliva properties, which may contribute to accelerated deterioration of the oral status in this population.

Association Between IL-6 Concentration and Diabetes-Related Variables in DM1 Patients with and without Microvascular Complications

Interleukin 6 (IL-6) plays an important role in the initiation and acceleration of chronic inflammation and could contribute to development of microvascular complications in patients with type 1 diabetes (DM1). Therefore, this study was aimed to investigate the association between concentration of IL-6 in relation to glucose control, lipid profile, and body mass index (BMI) in 69 DM1 patients subdivided according to the absence or presence of microvascular complications. BMI, level of fasting plasma glucose (FPG), and concentrations of total cholesterol (TCH), LDL cholesterol (LDL-C), and IL-6 were higher in DM1 patients compared to the control group. In DM1 patients, IL-6 concentration was positively correlated with level of FPG, LDL-C, TCH concentrations, and BMI. These correlations were stronger in the subgroup of patients with microvascular complications. In addition, BMI independently influences IL-6 concentration in DM1 patients. In conclusion, elevated IL-6 concentration is associated with diabetes-related variables which could accelerate progression of microvascular complications in DM1 patients.

The evaluation of IL-12 concentration, PAF-AH, and PLA2 activity in patients with type 1 diabetes treated with intensive insulin therapy

OBJECTIVES The aim of the study was to evaluate the concentration of interleukin 12 (IL-12), the activity of phospholipase A(2) (PLA(2)), and platelet-activating factor acetylhydrolase (PAF-AH) in type 1 diabetes (DM1) patients treated with intensive insulin therapy. DESIGN AND METHODS Studied parameters were measured in 81 patients, who were subdivided according to the HbA(1)c value, hsCRP concentration, and presence or absence of late complications. RESULTS PAF-AH activity was higher in the DM1 patients versus the control group (P=0.042). IL-12 concentration was the highest in subgroup with > or =3 mg/L hsCRP (P<0.05). Negative correlations were found for the IL-12 and age of patients and for apo A-I in the subgroup with poor metabolic control. In addition, positive correlation for hsCRP and PAF-AH activity in the subgroup with > or =3 mg/L CRP (P<0.05) was also found. CONCLUSIONS PAF-AH and IL-12 appear to be implicated in the development of a chronic inflammation in DM1. In addition, our results emphasize a protective role of apo A-I against an increase in IL-12 production.

Effect of Surgical Treatment on Lipid Peroxidation Parameters and Antioxidant Status in the Serum of Patients with Peripheral Arterial Disease

The various risk factors for peripheral arterial disease (PAD) are almost identical to those for atherosclerosis and include abnormal levels of lipids or lipoproteins. Lipid peroxidation parameters and total antioxidant capacity in the serum of male patients with PAD before surgery as well as 3–5 days and 7–10 days after surgery were measured. We also compared these parameters with those in a group of patients receiving simvastatin therapy. Concentrations of lipid hydroperoxides (LOOHs) and malondialdehyde, the total antioxidant capacity (assessed by ferric reducing antioxidant power assay), concentration of thiol (-SH) groups, and ceruloplasmin activity were determined spectrophotometrically in PAD patients treated surgically (Group I) or pharmacologically (Group II). The patients before surgical treatment had significantly higher concentrations of malondialdehyde but lower ceruloplasmin activity than those observed in Group II, treated with simvastatin. No significant differences before surgery in ferric reducing antioxidant power or thiol concentrations were found between the two groups. However, in Group I, both ferric reducing antioxidant power and thiol group concentrations decreased 3–5 days postoperatively, and ceruloplasmin activity increased 7–10 days after surgical treatment. The presented results demonstrate diverse oxidative stress responses to surgical treatment and confirm the beneficial effects of statin therapy in PAD.

Does oxidized LDL contribute to atherosclerotic plaque formation and microvascular complications in patients with type 1 diabetes

OBJECTIVE The aim of the study was to investigate whether changes in the level of oxidized LDL (oxLDL) over 2-years contribute to the development of subclinical macroangiopathy and/or microvascular complications in patients with DM1. DESIGN AND METHODS Basic clinical and biochemical parameters and oxLDL level were measured in 70 patients at baseline and after 2 years of the study. In addition, an ultrasonographic study was performed to assess the carotid intima media thickness (IMT). RESULTS Patients did not differ according to basic clinical and biochemical parameters at the beginning and after 2 years of the study. IMT increased (p=0.000001) whereas oxLDL level decreased (p=0.00001) in DM1 patients during 2 years. Multivariate regression analysis showed that oxLDL independently influences IMT in DM1 patients (β=0.454, R2=0.35). Further, positive correlations between oxLDL value and LDL-C concentration (r=0.585, p<0.05, n=70) and between oxLDL level and apo-B concentration have been established (r=0.610, p<0.05, n=70). Moreover, patients with chronic microvascular complications showed a higher value of IMT in comparison with patients without them (p=0.003). CONCLUSION Our results provide the evidence that oxLDL accelerates atherosclerotic plaque formation and may contribute to the development of microvascular complications in DM1.

The relationship between concentrations of magnesium and oxidized low density lipoprotein and the activity of platelet activating factor acetylhydrolase in the serum of patients with type 1 diabetes

The study was aimed at comparing the concentration of metabolic parameters, the serum concentration of oxidized low density lipoproteins (oxLDL) and the activity of platelet activating factor acetylhydrolase (PAF-AH) in the relation to the serum concentration of magnesium (Mg) in patients with type 1 diabetes (DM1). DM1 patients (n=78) were divided into 2 groups: patients with low serum Mg concentration (<0.7 mmol/L, group 1, n=34) and patients with reference levels of Mg (>or=0.7 mmol/L, group 2, n=44). A control group (n=24) of healthy subjects was also recruited. Our results showed that DM1 patients had lower serum Mg concentrations than the control group. It was found that parameters of poor metabolic control and lipid profile are not related to the serum Mg concentration in DM1 patients. However, both the Mg concentration and the PAF-AH activity are independently related to the serum oxLDL concentration. In group 1 the oxLDL concentration and the PAF-AH activity were higher than in group 2, and the control group. Two groups of DM1 patients did not show any differences with regard to the metabolic control. Therefore, the oxidative modification of LDL and the higher activity of PAF-AH are related with the low Mg status; however, no relation has been observed between these parameters and the poor metabolic control in DM1 patients.