Marzena Dworacka

IL-12 serum levels in patients with type 2 diabetes treated with sulphonylureas

Interleukin-12 (IL-12) has been identified as a pro-inflammatory cytokine which is thought to contribute to the development of atherosclerosis. However, to date, the various associations between factors related to the course of type 2 diabetes, like metabolic compensation, beta cell secretory dysfunction, insulin resistance and IL-12 serum levels, remain unclear. Our study involved 41 patients with type 2 diabetes, 19 patients with coronary artery disease (CAD), and 19 healthy controls. We measured serum levels of fasting glucose, HbA(1)c, 1,5-anhydro-d-glucitol, and lipids. In addition, serum levels of C-peptide, insulin, proinsulin and IL-12 were assayed. HOMA(IR) score was calculated. The serum concentrations of IL-12 were higher in diabetics than in either patients with CAD or healthy controls, and were correlated with BMI, C-peptide, insulin, HOMA(IR), proinsulin and HDL serum levels. Multiple regression analysis revealed that the IL-12 serum level in type 2 diabetics primarily is dependent upon fasting proinsulin concentration. Our results demonstrate that elevated IL-12 serum levels in type 2 diabetics treated with sulphonylureas are induced especially by peripheral insulin resistance and beta cells dysfunction, as expressed by fasting serum proinsulin levels. This finding gives us hope that treatment to decrease peripheral insulin resistance and to avoid excessive proinsulin secretion might be successful in the prevention of IL-12-induced atherosclerosis.

The Application of Plasma 1,5-Anhydro-D-glucitol for Monitoring Type 2 Diabetic Patients

Aim: Recent data have suggested that effective control of postprandial blood glucose can reduce the risk of macroangiopathic complications of diabetes, especially cardiovascular risk. 1,5-Anhydro-D-glucitol (1,5-AG) has been proposed as a marker of short-term hyperglycaemic excursions. We aimed to evaluate its usefulness in patients with type 2 diabetes and have attempted to indicate when 1,5-AG monitoring should be used in ordinary diabetes care settings. Methods: The study group consisted of 130 type 2 diabetic patients aged 36–69 years. 1,5-AG plasma level, HbA1c concentrations and daily glucose profile were measured. Mean blood glucose (MBG), M-value were calculated and maximal daily glycaemia (MxG) was established as indicators of short-term hyperglycaemic episodes. Results: 1,5-AG plasma level was negatively and HbA1c was positively correlated with fasting glycaemia (FG), MBG, M-value and MxG. Multivariate regression analysis revealed that 1,5-AG plasma level is determined by MxG only, while FG determined HbA1c concentration in blood. The analysis of 1,5-AG level and HbA1c distributions in well and poorly controlled patients revealed that persons with low HbA1c values may have decreased 1,5-AG plasma level. Conclusion: 1,5-AG plasma level monitoring is the useful method to identify well controlled, exclusively based on HbA1c levels type 2 diabetic patients with transient hyperglycaemia, accordingly patients at high risk of macroangiopathic complications.

Increased circulating RANTES in type 2 diabetes

AimThe pro-atherogenic role of RANTES, a chemokine expressing pleiotropic activities, in the course of type 2 diabetes-related atherosclerosis has been well documented. However, it is not known which of the diabetes-related factors primarily influence serum RANTES levels in patients with type 2 diabetes. Our aim was to investigate relationships between several factors known to be related to an increased risk of atherosclerosis and serum RANTES levels in type 2 diabetic patients.MethodsA total of 168 subjects were examined, which included 138 patients with type 2 diabetes and 30 non-diabetic controls. Measurements of venous, fasting, plasma glucose, HbA1c, lipid profile, 1,5-anhydro-D-glucitol (1,5-AG) plasma levels, homocysteine and the fasting, serum C-peptide levels were performed. Serum concentrations of RANTES were assayed using BD™ Cytometric Bead Array tests. Peripheral insulin resistance was expressed according to a new index defined by Ohkura et al.ResultsRANTES levels in type 2 diabetic patients correlated with 1,5-AG, fasting glycaemia, HbA1c and the Ohkura index. Multivariate regression analysis was performed taking into consideration several factors related to the inflammatory process and atherosclerosis, namely the patient’s age, diabetes duration, waist circumference, 1,5-AG, HbA1c, lipid profile parameters, serum homocysteine levels and Ohkura index, as independent variables potentially influencing serum RANTES levels in type 2 diabetic patients. It is shown that RANTES concentrations in the serum is primarily dependent upon 1,5-AG plasma levels.ConclusionOur results suggest that increased serum levels of RANTES in type 2 diabetic patients are closely related to postprandial (acute) hyperglycaemia.

Thymic emigration patterns in patients with type 2 diabetes treated with metformin

Recent data suggest that thymic output, which provides the naive T cells necessary for the normal functioning of T‐cell‐dependent immunosurveillance cellular immunity including anti‐cancer protection, can be disturbed in the course of type 2 diabetes. Metformin, an anti‐diabetic drug commonly confirmed as an agent with many potential anti‐cancer activities, might be helpful in this immune correction. The profile of thymic output was evaluated in the current study on the basis of the signal‐joint T‐cell receptor excision circle (sjTREC) concentration in peripheral blood polymorphonuclear cells and thymic emigrant content in peripheral blood evaluated from CD127 and/or CD132 antigen expression. It was revealed that recent thymic emigrants and more differentiated CD127+ CD132+ cell populations were decreased among naive T cells and CD8+ T cells, whereas RTE count was increased in CD4+ T cells, and the CD127+ CD132+ cell population was less numerous than in non‐diabetic participants. Terminally differentiated thymic emigrants, i.e. CD127− CD132+ cells, were increased in naive T cells and in CD8+ T cells. Metformin affects mainly the early phases of thymic export, increasing CD127+ CD132− and CD127+ CD132+ cell populations in naive T cells and the CD127+ CD132− population in CD4+ T lymphocytes. It could be concluded that type 2 diabetes deteriorates thymic immunostasis. The decreased thymic output could be compensated by metformin, especially with regard to CD4+ naive T cells. It is the first time that therapy with metformin has been documented by us as particularly useful in the control and normalization of thymus function, regarding correction of early populations of thymic emigrants.

Circulating monocyte chemotactic protein 1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1) and angiogenin in type 2 diabetic patients treated with statins in low doses

Statins are known as agents promoting a biphasic dose-dependent effect on angiogenesis under experimental conditions. Dysregulation of angiogenesis plays an important role in the development of atherosclerosis and it may be affected by metabolic factors. The aim of this research was to explain how low doses of statins modify serum concentrations of pro-angiogenic factors MCP-1 and angiogenin in type 2 diabetic patients. Measurements of metabolic control parameters were performed in 30 patients with type 2 diabetes treated with low doses of statin, and in 34 statin-free patients with type 2 diabetes. The serum levels of MCP-1 and VCAM-1 in statin-treated patients were lower than those of the statin-free group. ANCOVA results revealed that these effects were dependent only on the use of statins. In type 2 diabetic subjects, overall positive correlation was found between total cholesterol or LDL serum concentration and MCP-1 serum level. The angiogenin concentration in the serum did not show differences and was comparable in both groups. The angiogenin serum level correlated negatively with HDL, LDL and with HbA1c. Multivariate regression analysis indicated that angiogenin serum levels in type 2 diabetic patients were determined mainly by HbA1c, HDL-cholesterol and diabetes duration. It has been shown that statins used in low doses in type 2 diabetic subjects decrease MCP-1 and VCAM-1serum levels, most likely due to the statins-related effect on the lipid profile, while angiogenin serum levels in this group are determined rather by the current metabolic control.

Alpha-lipoic acid modifies circulating angiogenic factors in patients with type 2 diabetes mellitus.

AIMS In recent years interest has been focused on angiogenesis as a process involved in coronary artery disease (CAD) and diabetic distal sensorimotor polyneuropathy (DSPN). Recent studies have demonstrated the possible angiogenesis-modulating potential of alpha-lipoic acid (ALA) for DSPN and CAD. The aim of our study was to investigate the influence of ALA on serum angiogenic factors in patients with DM-2 (type 2 diabetes) with CAD and DSPN. METHODS Sixty patients with type 2 DM (T2DM) and CAD and 25 non-diabetic subjects were studied. Thirty patients with T2DM, CAD and DSPN were given 600 mg of ALA a day for 90 days. VEGF, bFGF, MCP-1, angiogenin, IL-12 and IL-10 concentrations in the sera were measured by flow cytometry. RESULTS ALA significantly increased VEGF, bFGF and IL-10 and decreased MCP-1 serum concentrations in patients with T2DM and CAD and DSPN. VEGF and IL-10 serum levels, both before and after ALA-treatment, were higher in this group than in T2DM and CAD patients, while circulating bFGF was higher and MCP-1 serum level lower in patients with T2DM and CAD and DSPN only in the post-ALA-treatment, compared to the T2DM and CAD group. CONCLUSIONS ALA may influence angiogenesis in type 2 diabetic patients through an effect on some circulating factors including VEGF, bFGF, MCP-1 and IL-10.

Circulating CD3+56+ Cell Subset in Pre-diabetes

The CD3+56+ cells are a small but significant population of T lymphocytes encompassing NKT-like and NKT cells, which may play the essential role at the very early stages of atherosclerotic plaque development. The frequency and activity of CD3+56+ cells in atherosclerosis-inducing dysglycaemic disease (diabetes type 2 or pre-diabetes) is largely unknown.We analysed CD3+56+ cell count, granzyme, perforin and annexin V profiles in the peripheral blood from a group of patients with pre-diabetes, with diabetes type 2 and from non-dysglycaemic controls. Measurements were made of fasting glucose levels, HbA1c, 1,5-anhydroglucitol and lipid profile.The mean counts of CD3+56+ cells were significantly higher in patients with pre-diabetes compared to both patients with diabetes and to control group. There was an increase in the number of CD3+56+ cells producing granzyme and perforin in pre-diabetic patients compared to other groups, while there were no difference in annexin V+ populations within examined groups. It was confirmed that CD3+56+ cells count is modified by metabolic factors and their parameters, namely HbA1c and 1,5-anhydroglucitol values.It could be stated that the alterations of CD3+ 56+  cells count in peripheral blood of pre-diabetic and type 2 diabetic patients are related to different grades of carbohydrate deteriorations - postprandial hyperglycaemia and chronic hyperglycaemia.

New arguments for beneficial effects of alpha-lipoic acid on the cardiovascular system in the course of type 2 diabetes

Purpose Alpha‐lipoic acid (ALA), widely known as an antioxidant, modifies also serum levels of angiogenic factors in type 2 diabetic patients. These pharmacological activities may influence the status of the cardiovascular system. Taking into consideration that diabetes is related to the increased cardiovascular risk we investigated several effects of ALA on angiogenic factors in the myocardium and in the aortal wall using a rat model of type 2 diabetes. Methods Diabetes was induced in Wistar rats by a fat‐rich diet and by intraperitoneal injection of a small dose of streptozotocin (30 mg/kg). Animals were divided into 3 groups: ALA‐treated type 2 diabetes rat model, placebo‐treated type 2 diabetes rat model and placebo‐treated non‐diabetic rats. ALA was administered orally once a day, 20 mg/kg, for 8 consecutive weeks. mRNA VEGF, VEGF‐R1 and VEGF‐R2 expression was measured in the myocardium and the aortal wall, simultaneously with circulating VEGF and circulating endothelial cells (cEC) and endothelial progenitor cells (cEPC). Results ALA induced pro‐angiogenic effect in the myocardium of rats with diabetes increasing mRNA VEGF expression and decreasing mRNA VEGFR‐1 expression, while in the aortal wall ALA increased mRNA VEGFR‐2 and VEGFR‐1 expression. cVEGF in the ALA‐treated group was higher comparing to both control groups. It was revealed that cEC percentage in the ALA‐treated group was decreased with no effect on the percentage of cEPC. Conclusions In summary, the current data provide novel findings about potential beneficial effects of ALA on angiogenic factors in the cardiovascular system, especially on myocardium, in the course of type 2 diabetes. Graphical abstract Figure. No caption available.

Homocysteine as a non-classical risk factor for atherosclerosis in relation to pharmacotherapy of type 2 diabetes mellitus

AIMS The aim of our study was to evaluate which of the pharmacotherapeutic methods that are frequently used to treat type 2 diabetes is associated with the most beneficial profile in relation to pro-atherogenic homocysteine levels. PATIENTS AND METHODS We measured the serum homocysteine level in 182 patients with type 2 diabetes treated with metformin (89), treated with insulin in combination with metformin (31), receiving sulfonylureas (31) and treated conventionally with insulin (31). The total homocysteine levels in the serum were assayed. To exclude the influence of selected metabolic and anthropometric factors on the differences between the examined groups, multivariate analysis of covariance was used (ANCOVA). In this analysis, serum homocysteine concentration was the dependent variable, while diabetes duration, waist circumference, HbA1c, 1,5-anhydro-D-glucitol, fasting glycaemia and peptide C were used as covariates. RESULTS The serum homocysteine levels in patients treated with insulin in monotherapy were significantly higher than what was observed in the metformin treated subjects and in the patients receiving insulin combined with metformin. The analysis of covariance also confirmed that the differences between the therapeutic groups were affected by waist circumference and the C-peptide levels. CONCLUSION We conclude that conventional insulin therapy may have a negative effect on pro-atherogenic homocysteine levels in patients with type 2 diabetes. This study revealed that pro-atherogenic homocysteine levels may not only be modified by pharmacotherapy of type 2 diabetes, but also by beta cell secretory function and abdominal obesity.

The Impact of Pharmacotherapy of Type 2 Diabetes Mellitus on IL-1β, IL-6 and IL-10 Secretion

Background: The aim of this study was to assess the impact of pharmacotherapy of diabetes on atherosclerosis, as reflected in interleukin (IL)-1β, IL-6 and IL-10 serum levels. Methods: We studied patients with type 2 diabetes, treated with metformin, insulin combined with metformin and conventional insulin. IL-1β, IL-6 and IL-10 serum levels were assayed using BD™ Cytometric Bead Array. Multivariate analysis of covariance was performed to exclude the impact of some metabolic and anthropometric factors on differences in cytokines concentrations among the participants receiving different pharmacotherapy. Results: The serum concentrations of IL-1β and IL-6 were significantly higher and IL-10 serum levels were significantly lower in the insulin-treated group than in other therapeutic groups. Covariance analysis confirmed that differences in IL-1β and IL-6 levels were determined by pharmacotherapy and fasting plasma glucose, whereas in IL-10 levels by the therapy only. Additionally, peptide C modified differences in IL-1β levels and HbA1c in IL-6 concentrations. Conclusion: This study revealed that both pharmacotherapy and glycemic control may modify some pro-atherogenic factors, such as IL-1β and IL-6. The therapy with metformin and insulin combined with metformin seems to be much more beneficial in terms of their impact on pro-inflammatory cytokines secretion in comparison to conventional insulinotherapy.