Fructosamine 3-kinase and glyoxalase I polymorphisms and their association with soluble RAGE and adhesion molecules in diabetes.

Advanced glycation end-products (AGEs) are key players in pathogenesis of long-term vascular diabetes complications. Several enzymes such as fructosamine 3-kinase (FN3K) and glyoxalase I (GLO I) are crucial in preventing glycation processes. The aim of our study was to evaluate an association of FN3K (rs1056534, rs3848403) and GLO1 rs4746 polymorphisms with parameters of endothelial dysfunction and soluble receptor for AGEs (sRAGE) in 595 diabetic and non-diabetic subjects. Genotypic and allelic frequencies of mentioned polymorphisms did not differ between subgroups. In diabetic patients significant differences were observed in sRAGE concentrations according to their rs1056534 and rs3848403 genotype. While GG and CG genotypes of rs1056534 with mutated G allele were associated with significant decrease of sRAGE (GG: 1055+/-458 and CG: 983+/-363 vs. CC: 1796+/-987 ng/l, p<0.0001), in rs3848403 polymorphism TT genotype with mutated T allele was related with significant sRAGE increase (TT: 1365+/-852 vs. CT: 1016+/-401 and CC: 1087+/-508 ng/l, p=0.05). Significant differences in adhesion molecules were observed in genotype subgroups of GLO1 rs4746 polymorphism. In conclusion, this is the first study describing significant relationship of FN3K (rs1056534) and (rs3848403) polymorphisms with concentration of sRAGE in patients with diabetes.

Skin autofluorescence relates to soluble receptor for advanced glycation end-products and albuminuria in diabetes mellitus.

The aim of this study was to compare skin autofluorescence caused by advanced glycation end-products (AGEs) with biochemical markers of endothelial dysfunction and soluble receptor for AGEs (sRAGE) in patients with diabetes. Skin autofluorescence (AF) assessed by AGE-Reader was evaluated with sRAGE and other biochemical parameters in 88 patients with diabetes (47 Type 1/T1DM/ and 41 Type 2/T2DM/) and 20 controls. Skin AF was significantly higher in T1DM and T2DM in comparison to controls (2.39 ± 0.54, 2.63 ± 0.73 versus 1.96 ± 0.33 AU; P < 0.0001). Positive correlation of AF with sRAGE was detected in T1DM and T2DM (r = 0.37, P < 0.02 and r = 0.60, P < 0.0001), but not in controls. Significantly higher AF values were found in patients with positive albuminuria as compared to those with normal albuminuria. Similarly, higher AF was detected in patients with endothelial dysfunction expressed by vWF, ICAM-1, and VCAM-1. Multiple regression analysis revealed independent association of skin AF with age, sRAGE, and albumin-creatinine ratio in patients with diabetes (R (2) = 0.38). Our study confirms that AF is elevated in patients with diabetes, especially with positive albuminuria and endothelial dysfunction. The strong and independent relationship between AF and sRAGE supports the idea that AF may reflect AGEs/RAGE interactions. The exact mechanism remains to be established.

Genetic and functional analyses of MRAS and HNF1A genes in diabetes and diabetic nephropathy.

Evidence has recently indicated that the MRAS and HNF1A genetic polymorphisms are associated with coronary artery disease. The MRAS and HNF1A genes are located on chromosomes 3q and 12q within the regions where associations with diabetes and diabetic nephropathy occur. We thus performed genetic and functional analyses of these two genes to evaluate their impacts on diabetes and diabetic nephropathy. MRAS and HNF1A genetic polymorphisms were genotyped in 1399 Czech subjects including non-diabetic controls (339), type 1 (243) and type 2 (817) diabetic patients with and without diabetic nephropathy using TaqMan allelic discrimination. Gene expression levels in the kidneys of diabetic Goto-Kakizaki and Wistar rats were detected with real-time RT-PCR. Despite no significance in genetic analysis of diabetic subjects, SNP rs2259816 in the HNF1A gene tended to associate with diabetic nephropathy in type 1 diabetic patients. The hnf1a gene expression was significantly decreased in kidney tissues of Goto-Kakizaki rats compared to Wistar and insulin-treated Goto-Kakizaki rats. There was neither significant association in the MRAS genetic polymorphism with diabetic nephropathy nor variation of mras gene expression in the kidneys of Goto-Kakizaki and Wistar rats. Data from the present study have not proved any significant association of the MRAS and HNF1A genetic polymorphisms with diabetes and diabetic nephropathy in a cohort of Czech population. However, the functional analysis and the trend in genetic analysis suggest that the HNF1A gene may have primary genetic impact on the development of diabetic nephropathy.

Microvascular Reactivity and Endothelial Function in Type 2 Diabetic Patients with Hyperlipidemia Treated with Simvastatin: 3-year Follow-up.

Aim of this study was to evaluate microvascular reactivity (MVR) by laser Doppler flowmetry in Type 2 diabetes mellitus (T2DM) with hyperlipidemia during three years of simvastatin treatment. Additionally, markers of endothelium and fibrinolysis were evaluated. Twenty patients with T2DM and hyperlipidemia were treated with 20 mg of simvastatin daily for 3 months, treatment was then interrupted for 3 months (wash-out) and again started and maintained continually up to total of 36 months of follow-up. Maximal perfusion (max), velocity of perfusion increase (max/t) and percent increase of perfusion compared to baseline (%) was measured during post-occlusive reactive hyperemia (PORH) and thermal hyperemia (TH). VCAM-1, ICAM-1, E-selectin and P-selectin were used as markers of endothelium, tissue plasminogen activator (tPA) and its inhibitor (PAI-1) as markers of fibrinolysis. Baseline MVR in diabetic patients was comparable to controls. MVR decreased at months 3, 12, and 36 compared to baseline (PORHmax 26+/-12, 35+/-17, 26+/-11 vs. 56+/-30 PU, p<0.05, THmax 67+/-19, 81+/-37, 58+/-24 vs. 134+/-70 PU, p<0.01, PORHmax/t 2.0+/-1.4, 2.8+/-1.7, 1.9+/-1.3 vs. 7.7+/-7.4 PU/s, p<0.05, THmax/t 1.1+/-0.6, 1.0+/-0.4, 0.7+/-0.4 vs. 1.5+/-0.7 PU/s, p<0.05.

Impaired microvascular reactivity and endothelial function in patients with Cushing's syndrome: influence of arterial hypertension.

The aim of the study was to evaluate skin microvascular reactivity (MVR) and possible influencing factors (fibrinolysis, oxidative stress, and endothelial function) in patients with Cushing's syndrome. Twenty-nine patients with active Cushing's syndrome (ten of them also examined after a successful operation) and 16 control subjects were studied. Skin MVR was measured by laser Doppler flowmetry during post-occlusive (PORH) and thermal hyperemia (TH). Malondialdehyde and Cu,Zn-superoxide dismutase were used as markers of oxidative stress. Fibrinolysis was estimated by tissue plasminogen activator (tPA) and its inhibitor (PAI-1). N-acetyl-beta-glucosaminidase, E-selectin, P-selectin, and ICAM-1 were used as markers of endothelial function. Oxidative stress and endothelial dysfunction was present in patients with hypercortisolism, however, increased concentration of ICAM-1 was also found in patients after the operation as compared to controls (290.8+/-74.2 vs. 210.9+/-56.3 ng.ml(-1), p<0.05). Maximal perfusion was significantly lower in patients with arterial hypertension during PORH and TH (36.3+/-13.0 vs. 63.3+/-32.4 PU, p<0.01, and 90.4+/-36.6 vs. 159.2+/-95.3 PU, p<0.05, respectively) and similarly the velocity of perfusion increase during PORH and TH was lower (3.2+/-1.5 vs. 5.2+/-3.4 PU.s(-1), p<0.05, and 0.95+/-0.6 vs. 1.8+/-1.1 PU.s(-1), p<0.05, respectively). The most pronounced impairment of microvascular reactivity was present in patients with combination of arterial hypertension and diabetes mellitus.

Genetic influences of the intercellular adhesion molecule 1 (ICAM-1) gene polymorphisms in development of Type 1 diabetes and diabetic nephropathy.

AIM: The intercellular adhesion molecule-1 (ICAM-1) gene is located on chromosome 19p13, which is linked to Type 1 diabetes (T1D). ICAM-1 expression is related to development of T1D and diabetic nephropathy. The present study aims to evaluate the genetic influence of ICAM-1 gene polymorphisms on the development of T1D and diabetic nephropathy. METHODS: Five valid single nucleotide polymorphisms (SNPs) were genotyped in 432 T1D patients (196 patients had diabetic nephropathy) and 187 non-diabetic control subjects by using dynamic allele-specific hybridization (DASH) and pyrosequencing. RESULTS: SNPs rs281432(C/G) and rs5498 E469K(A/G) had high heterozygous indexes. They were significantly associated with T1D [P = 0.026, OR = 1.644 (95% CI 1.138-2.376) and P < 0.001, OR = 2.456 (1.588-3.8)]. Frequencies of the C allele in SNP rs281432(C/G) and the A allele in SNP rs5498 E469K(A/G) increased stepwise from non-diabetic control subjects to T1D patients without diabetic nephropathy and T1D patients with diabetic nephropathy. Further analysis for these two SNPs indicated that T1D patients had increased frequency of the common haplotype C-A, in comparison with non-diabetic control subjects (38.1 vs. 32.1%, P = 0.035). CONCLUSION: The present study provided evidence that SNPs rs281432(C/G) and rs5498 E469K(A/G) in the ICAM-1 gene confer susceptibility to the development of T1D and might also be associated with diabetic nephropathy in Swedish Caucasians.

Relationship between peripheral diabetic neuropathy and microvascular reactivity in patients with type 1 and type 2 diabetes mellitus -- neuropathy and microcirculation in diabetes.

The aim of the study was to evaluate differences in the relationship between peripheral diabetic neuropathy and microvascular reactivity in type 1 and type 2 diabetic patients. Twenty-eight type 1 and 37 type 2 diabetic patients were included in the study. Control groups consisted of 18 and 25, age and body mass index matched healthy persons. The presence of peripheral neuropathy was estimated by vibration perception threshold higher than 20 V evaluated by biothesiometry. Microvascular reactivity was examined by laser doppler fluxmetry using postocclusive reactive hyperemia and thermal hyperemia. The following variables of vascular reactivity were examined: peak flow after occlusion as a difference between maximal and basal perfusion (PORH (max)), mean velocity increase during postocclusive hyperemia (PORH (max)/t (1)), peak flow during thermal hyperemia (TH (max)) and the mean velocity increase in the perfusion during thermal hyperemia (TH (max)/t (2)). These parameters are expressed in perfusion units (PU) or in perfusion units per second (PU . s (-1)). The microvascular reactivity in type 1 diabetic patients without evidence of peripheral neuropathy was comparable with that in healthy persons and it was significantly higher than in type 1 diabetic patients with peripheral neuropathy in all tested parameters (PORH (max): 64 [40; 81] PU vs. 24 [17; 40] PU, p < 0.001, PORH (max)/t (1): 5.41 [2.69; 8.18] PU/s vs. 1.21 [0.69; 2.5] PU/s, p < 0.001, TH (max): 105 [77; 156] PU vs. 56 [46; 85] PU, p < 0.001 and TH (max)/t (2): 2.48 [1.67; 3.33] PU/s vs. 0.87 [0.73; 1.06] PU/s, p < 0.001). On the contrary, no difference in the microvascular reactivity parameters was found between type 2 diabetic patients with and without neuropathy (PORH (max): 48 [30; 60] PU vs. 49 [36; 57] PU, NS, PORH (max)/t (1): 3.46 [2.15; 5.19] PU/s vs. 3.29 [2.45; 4.8] PU/s, NS, TH (max): 95 [78; 156] PU vs. 97 [73; 127] PU, NS and TH (max)/t (2): 1.45 [0.95; 2.84] PU/s vs. 1.37 [1.12; 1.95] PU/s, NS). In both these groups microvascular reactivity was comparable with that estimated in the age and BMI matched healthy persons. An inverse relationship was observed between microvascular reactivity and vibratory perception threshold in type 1 diabetic patients, but it was not true in type 2 diabetic patients. We suppose that the pathogenesis of neuropathy and impaired microvascular reactivity may be differently influenced by metabolic factors in type 1 and type 2 diabetic patients.

Screening for associated autoimmunity in type 1 diabetes mellitus with respect to diabetes control.

As an autoimmune disease, type 1 diabetes mellitus (DM) can be associated with other autoimmune disorders. The aim of this study was to detect subclinically associated autoimmune thyroid disease, coeliac disease, and Addison's disease. The presence of autoantibodies was evaluated with special regard to the control of diabetes and to the clinical status of the patient. Fifty-one type 1 diabetic patients (22 men, 29 women, mean age 37+/-11 years, mean duration of diabetes 16+/-13 years) were included into this study. Specific antibodies to islet antigens--glutamic acid decarboxylase (GAD65), protein thyrosine phosphatase IA-2alpha, and to thyroid autoantigens--thyroid microsomal peroxidase (TPO) and thyroglobulin (TG) and also thyroid stimulating hormone (TSH) were measured by RIA. Autoantigens of the small intestine--tissue transglutaminase autoantibodies (ATTG), IgA and IgG antibodies to gliadin (AGA-IgA, AGA-IgG) were evaluated by ELISA. Endomysial autoantibodies (EMA) and adrenal cortex antibodies (ACA) were detected by indirect immunofluorescence microscopy. Eleven new cases of thyreopathy (22 % of patients) were detected by the assessment of thyroid autoantibodies and TSH. Two new cases of thyreotoxicosis were diagnosed during the study. Coeliac disease was diagnosed in at least two cases. Addison's disease was not diagnosed, although the ACA were positive in two patients. No influence of single or combined autoantibody positivity on the control of diabetes was found if normal organ function was preserved. In both patients with thyreotoxicosis the control of diabetes was worsened and improved after treatment. The screening of autoantibodies in type 1 diabetic patients could reveal subclinical cases of AITD or coeliac disease. Subclinical forms of these disorders have no influence on diabetes control. However, impaired organ function may be associated with the worsened control of diabetes as we demonstrated on two newly diagnosed cases of thyreotoxicosis. We suggest the need for the follow-up of patients with positive autoantibodies because further deterioration of the respective organs can be expected.

[Effect of hypercortisolism on development of atherosclerotic changes in blood vessels]. / Vliv hyperkortizolismu na vznik a vývoj aterosklerotických cévních zmen.

UNLABELLED: Hypercortisolism is associated with a high risk of sickness rate and death rate particularly in view of facilitated arteriosclerotic processes. It is most frequently induced by drug therapy, but endogenous hypercortisolism (Cushing's syndrome) may serve as a suitable model of the effect of hypercortisolism on vascular wall. Our cohort included the following groups of patients and control individuals: 1. a group of patients with florid so far untreated Cushing's syndrome--14 patients, 2. a control group to these patients--16 individuals, 3. a group recently operated on and healed-up patients with Cushing's syndrome--8 patients, 4. a group of previous of previous cured-up patients with Cushing's syndrome--27 subjects, 5. a control group to those patients of group 4--17 persons. The following differences were found between the respective groups: 1. the ultrasonographic examination of carotid arteries demonstrated sclerotic plates or carotid stenosis in 21.3% of patients with florid Cushing's syndrome and 41.4% in patients with corticolism having been cured-up against 11.7% in the relevant control group; 2. the examination of skin microcirculation by the laser-doppler method revealed a lower velocity of perfusion increase during examination of postocclusion hyperemia in patients with florid Cushing's syndrome and hypercortisolism having been cured-up against a control group (CUSH., P < 0.04; previous cured-up, P < 0.02) as well as thermally-induced hyperemia (CUSH., P < 0.03; formerly cured-up, P < 0.04); 3. the laboratory examination of patients with florid Cushing's syndrome revealed higher values of LDL-cholesterol (P < 0.05) and total cholesterol (P < 0.001), malonyldialdehyde as an indicator of increased formation of oxygen radicals (P < 0.05) and oromucoid, the protein of acute phase, signaling a chronic inflammation (P < 0.05); 4. in patients who previously suffered from hypercortisolism increased levels of fibrinogen (P < 0.03) and the cytoadhesive molecule ICAM-1 (P < 0.05) were accompanied by decreased levels of the growth factor of vascular endothelia (VEGF) (P < 0.05) against patients with florid Cushing's syndrome. CONCLUSION: The findings of the examinations performed indicate that increased incidence of arteriosclerotic processes is present in patients with the florid Cushing's syndrome as well as in those who have suffered from Cushing's syndrome before.

[Microvascular reactivity in type 2 diabetes mellitus and its relation to IGF-I and its binding proteins]. / Reaktivita mikrocirkulace u diabetes mellitus 2. typu a její vztah k systému IGF-I a jeho vazebných proteinu.

BACKGROUND AND AIM: System of insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBP) may be involved in the pathogenesis of vascular damage in Type 2 diabetes. Aim of the study was to analyse the relationship between this system and microvascular reactivity in Type 2 diabetes as measured by laser-Doppler flowmetry. METHODS AND RESULTS: Thirteen Type 2 diabetic patients (8 women and 5 men) with microangiopathy and fifteen healthy subjects (8 women and 7 men) were examined clinically, underwent laser-Doppler flowmetry and intima-media thickness measurements. Fasting serum levels of IGF-I, IGFBP and lipids were examined. Percentage perfusion increase in the test with postocclusive reactive hyperaemia (PORH) as well as in that with thermal hyperaemia (TH) were significantly decreased in Type 2 diabetic patients (p < 0.05). Maximal perfusion after heating (THmax) was lower in Type 2 diabetic patients. Reaction of microcirculation after heating (THmax/t) was slower in Type 2 diabetic patients (p < 0.001). The changes in microvascular reactivity didn't significantly correlate with any of measured parameters of IGF-I/IGFBP system. CONCLUSIONS: Microvascular reactivity is impaired in Type 2 diabetic patients. The function of microcirculation is not significantly related to the particular parameters of the IGF-I/IGFBP system.

Microvascular reactivity in patients with hypercholesterolemia: effect of lipid lowering treatment.

Impaired NO-dependent vasodilation of resistance vessels is an early marker of an increased risk of atherosclerosis; utility of the examination of microcirculation, however, is far less established. We have therefore tested the hypothesis that hypercholesterolemia is associated with an impaired microvascular reactivity and that this defect is at least partially reversible by lipid-lowering treatment. Twenty-seven otherwise healthy patients with severe hypercholesterolemia (HLP) were examined at rest and then after 10 weeks of atorvastatin treatment (20 mg/day). Skin microvascular reactivity (MVR) was examined by laser-Doppler flowmetry. Baseline MVR values of the studied group were compared to healthy control subjects, HLP patients with coronary artery disease (CAD) and diabetic patients with and without diabetic retinopathy. MVR was normal in HLP subjects without CAD. On the contrary, MVR was impaired in HLP patients with CAD. There was no effect of atorvastatin on MVR, despite the profound reduction of serum lipids. MVR values did not correlate with cholesterol levels. In diabetic subjects, the MVR was substantially impaired only in patients with retinopathy. In the subjects without retinopathy, MVR was either normal (type I diabetes) or moderately impaired (type II diabetes). MVR was thus normal in HLP patients without manifest vascular disease and was not influenced by lipid lowering therapy. Impairment in the MVR was only evident in subjects with HLP and severe CAD. These results suggest that microcirculation is not involved in the early vascular dysfunction induced by HLP and that MVR rather reflects changes which appear later in the course of the atherosclerotic disease.

The relationship between the IGF-I system and its binding proteins and microvascular reactivity in Type 1 diabetes mellitus.

The system of IGF-I and its binding proteins may be involved in the pathogenesis of vascular damage in Type 1 diabetes. The aim of this study was to analyze the relationship between this system and the microvascular reactivity in Type 1 diabetes as measured by laser-Doppler flowmetry. Twenty-two Type 1 diabetic patients (13 women and 9 men) with microangiopathy and fifteen healthy subjects (8 women and 7 men) were examined clinically, underwent laser-Doppler flowmetry and intima-media thickness measurements. Fasting serum levels of IGF-I, free IGF-I, IGFBPs and lipids were examined. The microvascular reactivity was impaired in Type 1 diabetic patients. Maximal perfusion during post-occlusive reactive hyperemia (PORHmax) and during thermal hyperemia (THmax) was significantly decreased in Type 1 diabetes (p<0.01). Percentage perfusion increase in both tests (PORH and TH) was lower in Type 1 diabetes mellitus (p<0.01) and the reaction after heating was slower in diabetic patients (THmax) (p<0.01). We did not find any significant dependence of microvascular reactivity on the parameters of IGF-I or its binding proteins. We conclude that the microvascular reactivity is impaired in Type 1 diabetes mellitus, but this impairment is not clearly dependent on the activity of the IGF-I system. It is probably only a complementary pathogenic factor.

Reduced microvascular perfusion and reactivity in adult GH deficient patients is restored by GH replacement.

BACKGROUND: An increased cardiovascular risk and mortality in hypopituitary patients receiving conventional hormonal treatment without GH replacement have been shown in several studies. Various atherogenic risk factors including endothelial dysfunction - an early event in the atherogenesis - are more expressed in adults with GH-deficiency (GHD). Changes in microcirculation and vascular reactivity could represent an early marker of developing vascular changes. OBJECTIVE: To evaluate the microcirculation and vascular reactivity in a GHD state before and during GH replacement. SUBJECTS, METHODS AND DESIGN: Thirteen adult patients (ten men, mean age 40+/-9 years) with severe GHD were studied. The skin microvascular perfusion and reactivity were measured by laser-Doppler flowmetry on the forearm. Two dynamic tests for vascular perfusion and reactivity were used - postocclusive reactive hyperemia (PORH) and thermal hyperemia (TH) at 44 degrees C. Measurements were performed before and after 6 and 12 months on GH replacement with a dose of GH that normalized IGF-I serum levels. The parameters of tissue perfusion and vascular reactivity measured in GHD were compared with values during GH treatment and with the results of the control group. RESULTS: Peak flow during TH in GHD patients was significantly reduced before GH treatment when compared with healthy subjects (means+/-s.e.m., 68+/-6.6 vs 111+/-8.3 perfusion units (PU), P<0.001) and normalized on GH treatment (109+/-12.7 PU). The velocity of perfusion increase during TH before treatment was significantly reduced in GHD as well (0.84+/-0.07 vs 1.53+/-0.19 PU/s, P<0.03) and normalized on GH treatment (1.38+/-0.24 PU/s). The PORH was also significantly reduced in GHD compared with controls (PORH(max) 414+/-63 vs 528+/-58%, P<0.05) and during GH treatment was restored to values not different from controls (642+/-86%, P=NS). CONCLUSIONS: Skin microcirculation and vascular reactivity measured by laser-Doppler flowmetry is significantly reduced in GHD adults and is restored during GH replacement therapy. Reduced tissue perfusion and reactivity probably reflect the endothelial dysfunction in the GHD state. Reduced nitric oxide production and bioavailability and also other factors like increased sympathetic activity and reduced conversion of thyroxine to triiodothyronine in the GHD state can contribute to changes in microcirculation. Restoration of vascular reactivity by GH replacement might have favorable clinical consequences on the increased vascular morbidity of GHD patients. Reduced skin microvascular perfusion and reactivity in GHD probably contribute to the impaired thermoregulation - a clinical symptom of GHD.

The relationship between serum levels of insulin-like growth factor-I and its binding proteins and microvascular function in acromegalic patients.

The system of insulin-like growth factor-I (IGF-I) and its binding proteins is thought to be involved in the pathogenesis of vascular damage under different pathological circumstances. The results of various studies are rather controversial. This study considers the relationship between the activity of this system and the function of microcirculation in acromegalic patients. Thirteen patients with hormonally active acromegaly and 15 healthy controls were included in the study. The growth hormone, free IGF-I, IGF-I, IGF binding protein (IGFBP) -1, -2, -3 and -6 serum levels and parameters of lipid metabolism were determined. The function of microcirculation was determined by laser Doppler fluxmetry and the intima media thickness of the common carotid artery was measured by ultrasound. We noted significant reduction in postocclusive reactive hyperaemia (PORH(max)) (P < 0.01), in thermal hyperaemia (TH(max)) (P < 0.05) and in the velocity of reaction in both tests in the group of acromegalic patients. A significant negative correlation between free IGF-I serum levels and maximal perfusion during thermal hyperaemia TH(max) (P < 0.02) was found in the control group. Statistically significant positive correlation between free IGF-I serum levels and the time to maximal perfusion in postocclusive reactive hyperaemia PORH(max) (P < 0.05) was found in the group with hormonally active acromegaly. Moreover, a positive relationship between IGFBP-1 serum levels and serum levels of total (P < 0.01) and low density lipoprotein (LDL) (P < 0.05) cholesterol was found in the group of patients with acromegaly. We conclude that the function of microcirculation is impaired in patients with acromegaly and that free IGF-I serum levels may affect the microvascular function as measured by laser Doppler fluxmetry. In addition, we found a significant relationship between the serum levels of IGFBP-1 and those of total and LDL cholesterol in the group of patients with hormonally active acromegaly.

Association of obesity, diabetes, serum lipids and blood pressure regulates insulin action.

Insulin resistance is present in patients with Type 2 diabetes mellitus as well as in obese patients without diabetes. The aim of our study was to compare insulin action in diabetic and control persons with or without obesity and to evaluate the influence of serum cholesterol, serum triglyceride and blood pressure on metabolic variables of insulin action. We examined 42 Type 2 diabetic patients and 41 control persons with body mass index (BMI) from 21.1 to 64.5 kg x m(-2), and 33 to 71 years old. The isoglycemic hyperinsulinemic clamp technique was performed at an insulin infusion rate of 1 mU x kg(-1) x min(-1) during 120 min. We evaluated the metabolic clearance rate of glucose (MCR(G), ml x kg(-1) x min(-1)) as the most important indicator of insulin action by isoglycemic clamp. The Pearson's correlation and multiple regression models were used to compare studied factors with the insulin action. We found following predictors of insulin resistance expressed in the relationship with MCR(G): BMI (r = -0.68, p<0.001), plasma glucose concentration (r = -0.66, p<0.001), cholesterol (r=-0.55, p<0.001), triglycerides (r = -0.54, p<0.001) and mean blood pressure (r = -0.38, p<0.01). From the multiple regression analysis we conclude that obesity may have even greater influence on the insulin action than diabetes mellitus itself.

Serum leptin levels in patients with primary hyperaldosteronism before and after treatment: relationships to insulin sensitivity.

BACKGROUND: Leptin is a protein hormone produced predominantly by adipocytes that plays a role in food intake regulation and a series of other physiological processes including blood pressure regulation. OBJECTIVES: The aim of our study was to compare serum leptin levels in patients with primary hyperaldosteronism (PA) with those of healthy subjects and to explore the relationship of serum leptin levels and the parameters of insulin action in these patients before and after surgical or pharmacological treatment. METHODS: Serum potassium, leptin, aldosterone, insulin levels and plasma renin activity were measured and hyperinsulinaemic euglycaemic clamp was performed in 11 patients with PA and 11 healthy age-, gender- and body mass index (BMI)-matched subjects. In eight of 11 patients the same measurements were repeated at least 6 months after surgical or pharmacological treatment. RESULTS: The basal serum leptin levels in PA patients did not significantly differ from those of healthy subjects (mean+/-s.e.m. 8.4+/-1.9 vs 11.2+/-1.8 ng/ml, P=0.30), although their insulin sensitivity was significantly impaired (PA patients vs control subjects: glucose disposal rate in the last 20 min of clamp (M) 18.7+/-1.8 vs 30.6+/-3.3 micromol/kg/min, metabolic clearance rate of glucose (MCR(g)) 3.9+/-0.5 vs 7.2+/-1.1 ml/kg/min, P<0.05). The surgical or pharmacological treatment of PA patients increased significantly their serum leptin levels (10.9+/-3.7 vs 8.4+/-1.9 ng/ml, P<0.05) and simultaneously improved their insulin sensitivity. Basal serum leptin levels in both groups correlated positively with BMI and serum insulin levels. The inverse relationship between serum leptin levels and the insulin sensitivity parameters was found in both PA patients before treatment and healthy subjects. These relationships disappeared after treatment of PA patients except for those between serum leptin levels and MCR(g). CONCLUSION: Basal serum leptin levels in untreated patients with PA do not significantly differ from those of healthy subjects, but increase significantly after surgical or pharmacological treatment. The increase in serum leptin levels is paradoxically accompanied by the improvement of insulin sensitivity in these patients.

[Effect of insulin in polycystic ovary syndrome]. / Pusobení inzulínu u syndromu polycystických ovarií.

BACKGROUND: Polycystic ovary syndrome (PCOS) has been accompanied by insulin resistance. The aim of this study was to compare the insulin action between thin and obese women with PCOS and to analyse its relationship to serum concentration of selected hormones. METHODS AND RESULTS: Total number of 32 women with PCOS between them there were 22 thin and 10 obese subjects was examined in this study. Control group consisted of 21 nonobese healthy women. The insulin action was determined by euglycemic hyperinsulinemic clamp. Normal insulin action found in the group of thin women with PCOS was comparable with that in healthy controls whereas insulin resistance was observed in obese ones. An inverse relationship was found between insulin action and body mass index (r = 0.62, p < 0.01). By using HOMA index this relationship to BMI was on the borderline significance. No correlation was observed between insulin action and serum hormone concentrations (testosterone, androstendione, LH, FSH) but sex hormone binding globulin (SHBG) positively correlated with parameters of insulin action (r = 0.50-0.54). CONCLUSIONS: The insulin action may be normal in thin women with PCOS whereas obesity and other not yet disclosed factors influence development of insulin resistance in women with polycystic ovary syndrome.

[Changes in microcirculation and selected laboratory parameters in the early stages of diabetic microangiopathy]. / Zmeny mikrocirkulace a vybraných laboratorních parametru v casných stadiích diabetické mikroangiopatie.

BACKGROUND: Early stages of diabetic microangiopathy are accompanied with dysfunction, manifested by changes of some biochemical parameters. Parallel changes were observed in microcirculation. The aim of this study was to compare microcirculation in the skin of a forearm evaluated by laser Doppler with selected laboratory markers of endothelial dysfunction in Type 1 diabetes mellitus without microangiopathy or with incipient microangiopathy. METHODS AND RESULTS: Group of 43 Type 1 diabetic patients was examined in this study. 20 of them had no signs of microangiopathy and in 23 patients a simple diabetic retinopathy (background retinopathy) was diagnosed. Control group consisted of 25 healthy persons of comparable age, sex, and body mass index. All persons involved in this study were examined by laser Doppler and by biochemical examination and the results were compared. In comparison with control group, in diabetic patients the arm occlusion significantly lowered the increase of perfusion (29 +/- 12 vs. 41 +/- 18 perfusion units (PU) p < 0.01). Similarly the perfusion velocity increase was significantly lower in diabetic patients than in healthy controls (p < 0.01). Also the velocity of the perfusion increase after the warming up was lower in the diabetic than in non-diabetic persons (p < 0.01). Such changes of perfusion or those of velocity of perfusion increase were significantly lower in diabetic patients with microangiopathy than in those without this complication. Perfusion increases after both stimuli highly correlated (r = 0.86, p < 0.001). In diabetic patients with microangiopathy significantly higher N-acetyl-beta-glucosaminidase (NAG) activities in serum and E-selection or ICAM-1 concentrations were found as compared with patients without microangiopathy, whereas plasma concentrations of tissue plasminogen activator (tPA) or inhibitor (PAI-1) were comparable with those in the control group. NAG activity inversely correlated with velocity of the perfusion increase after both the occlusion (r = -0.41, p < 0.01) and the warming (r = -0.38, p < 0.05). Similar relationship was found between tPA or E-selectin and the velocity of the perfusion increase after the occlusion (r = -0.48, p < 0.01). CONCLUSIONS: Our results confirm that biochemical parameters and microcirculation are impaired in the early stage of microangiopathy in Type 1 diabetic patients. Detailed analysis showed that both types of examination offer slightly different information on the vascular status. A long prospective study in diabetic patients without incipient vascular changes will be necessary to evaluate if biochemical or microcirculatory changes can bring an earlier information on the developing angiopathy.

Comparison of laser-Doppler flowmetry with biochemical indicators of endothelial dysfunction related to early microangiopathy in Type 1 diabetic patients.

The aim of this study was to compare biochemical markers of endothelial activation with microcirculation measured by laser-Doppler flowmetry in Type 1 diabetic patients with or without microangiopathy. A total of 44 Type 1 diabetic patients were subdivided into those with (n=24) and without (n=20) microangiopathy according to ophthalmological findings and the presence or absence of microalbuminuria. The control group consisted of 25 healthy people of comparable age, sex, and body mass index. Postocclusive reactive hyperemia (PORH) and thermal hyperemia (TH, at 44 degrees C) were measured at the forearm. Serum N-acetyl-beta-glucosaminidase (NAG) activity, serum E-selectin, and ICAM-1 concentrations were used as biochemical markers of endothelial dysfunction. A significantly lower velocity of perfusion increase during postocclusive hyperemia (PORH(max) x t(1)(-1)) and during thermal hyperemia (TH(max) x t(2)(-1)) (P<.01) were accompanied by higher serum NAG activity (20.9+/-4.6 vs. 16.3+/-2.5 U l(-1), P<.01) in diabetic patients with microangiopathy as compared to healthy persons. An inverse relationship was found between PORH(max) x t(1)(-1) and NAG (r=-.33) results in diabetic patients. In addition, higher mean values of serum NAG activity, E-selectin, and ICAM-1 concentrations were associated with significantly lower values of microcirculation parameters (PORH(max) x t(2)(-1) and TH(max) x t(2)(-1)) in six patients without microangiopathy who had at least one of the above biochemical markers higher than mean+2 S.D. range. We suggest that serum NAG activity, E-selectin, and ICAM-1 concentrations may be used together with laser-Doppler flowmetry in Type 1 diabetic patients as early indicators of vascular changes in very early stage of diabetic microangiopathy.

[IGFBP-1 and its protective role in the pathogenesis of microangiopathy in type 1 diabetes mellitus]. / IGFBP-1 a jeho protektivní úloha v patogenezi mikroangiopatie u diabetes mellitus 1. typu.

BACKGROUND: The role of IGF-I/IGFBP's system in the pathogenesis of diabetic vascular complications is widely discussed in the literature. We studied the influence of this system on microvasculature in patients with type 1 diabetes with respect to the effect of IGFBP-1. METHODS AND RESULTS: 17 patients with type 1 diabetes were included in the study. We examined IGF-I, IGFBP-1 and IGFBP-3 serum levels, parameters of compensation of diabetes and basic values of lipid metabolism. The function of microvasculature was examined using the laser-Doppler system Periflux. We didn't found any relation between the total IGF-I serum levels, parameters of lipid metabolism or level of diabetes compensation and the degree of impairment of the function of microcirculation. IGFBP-1 serum levels positively correlated with the peak perfusion in thermal hyperaemia (r = 0.39; p < 0.03). IGFBP-3 serum levels did not affect the function of microcirculation. CONCLUSION: We can conclude that the activity of IGF-I/IGFBP's system belongs to factors contributing to the development of diabetic microangiopathy in type 1 diabetes. IGFBP-1 as the modulator of IGF-I activity plays probably protective role against the progression of microangiopathy. These results correspond with observations of some other authors.