Diabetes mellitus is associated with a variety of cardiovascular complications including impaired cardiac muscle function. The effects of insulin treatment on heart rate, body temperature and physical activity in the alloxan (ALX)-induced diabetic rat were investigated using in vivo biotelemetry techniques. The electrocardiogram, physical activity and body temperature were recorded in vivo with a biotelemetry sy stem for 10 days before ALX treatment, for 20 days following administration of ALX (120 mg/kg) and thereafter, for 15 days whilst rats received daily insulin. Heart rate declined rapi dly after administration of ALX. Pre-ALX heart rate was 321 ± 9 beats per minute, falling to 285 ± 12 beats per minute 15-20 days after ALX and recovering to 331±10 beats per minute 5-10 days after commencement of insulin. Heart rate variabilit y declined and PQ, QRS and QT intervals were prolonged after administration of ALX. Physical activity and body temperature declined after administration of ALX. Pre-ALX body temperature was 37.6 ± 0.1 °C, falling to 37.3 ± 0.1 °C 15-20 days after ALX an d recovering to 37.8±0.1 °C 5-10 days after commencement insulin. ALX-induced diabetes is associated with disturbances in heart rhythm, physical activity and body temperature that are variously affected during insulin treatment., F. C. Howarth ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Elevated levels of insulin have been reported to induce both an arterial vasodilation mediated by nitric oxide (NO), and vasoconstriction mediated by endothelin and reactive oxygen radicals. Metformin, used to control blood glucose levels in type 2 diabetes, has also been shown to cause NO-mediated dilation of conduit arteries. It is possible that these contradictory vascular effects are due to a non-direct action on arteries. Therefore, the direct effect of high levels of insulin and metformin infusion on resistance artery diameter was evaluated. Experiments were carried out on the anesthetized pig; blood flow and pressure were measured in the iliac artery. An adjustable snare was applied to the iliac above the pressure and flow measurement site to induce step decreases (3-4 occlusions at 5 min intervals were performed for each infusion) in blood flow, and hence iliac pressure, and the conductance (Δflow / Δpressure) calculated. Saline, insulin (20 and 40 mUSP/l/min), and metformin (1 μg/ml/min) were infused separately downstream of the adjustable snare and their effect on arterial conductance assessed. Insulin at both infusion rates and metformin caused a significant reduction in peripheral vascular conductance. In conclusion, hyperinsulinemia and metformin infusion constrict resistance arterial vessels in vivo., F. Markos, C. M. Shortt, D. Edge, T. Ruane-O'Hora, M. I. M. Noble., and Obsahuje bibliografii
PPAR-α agonists improve insulin sensitivity in rodent models of obesity/insulin resistance, but their effects on insulin sensitivity in humans are less clear. We measured insulin sensitivity by hyperinsulinemic-isoglycemic clamp in 10 obese females with type 2 diabetes before and after three months of treatment with PPAR-α agonist fenofibrate and studied the possible role of the changes in endocrine function of adipose tissue in the metabolic effects of fenofibrate. At baseline, body mass index, serum glucose, triglycerides, glycated hemoglobin and atherogenic index were significantly elevated in obese women with type 2 diabetes, while serum HDL cholesterol and adiponectin concentrations were significantly lower than in the control group (n=10). No differences were found in serum resistin levels between obese and control group. Fenofibrate treatment decreased serum triglyceride concentrations, while both blood glucose and glycated hemoglobin increased after three months of fenofibrate administration. Serum adiponectin or resistin concentrations were not significantly affected by fenofibrate treatment. All parameters of insulin sensitivity as measured by hyperinsulinemic-isoglycemic clamp were significantly lower in an obese diabetic group compared to the control group before treatment and were not affected by fenofibrate administration. We conclude that administration of PPAR-α agonist fenofibrate for three months did not significantly affect insulin sensitivity or resistin and adiponectin concentrations in obese subjects with type 2 diabetes mellitus. The lack of insulin-sensitizing effects of fenofibrate in humans relative to rodents could be due to a generally lower PPAR-α expression in human liver and muscle., K. Anderlová, R. Doležalová, J. Housová, L. Bošanská, D. Haluzíková, J. Křemen, J. Škrha, M. Haluzík., and Obsahuje bibliografii a bibiografické odkazy
Lipoprotein (a) [Lp(a)] is an LDL-like particle that contains an apolipoprotein B100 molecule covalently bound to a plasminogen-like glycoprotein, apolipoprotein (a) [apo(a)]. Epidemiological evidence supports a direct and causal association between Lp(a) levels and coronary risk. On the contrary, a few prospective findings demonstrate inverse association of Lp(a) levels with risk of type 2 diabetes (T2DM). The aim of our study was to evaluate the association of Lp(a) with indicators of insulin resistance (IR) and metabolic syndrome (MS), which precede development of T2DM. We enrolled 607 asymptomatic dyslipidemic subjects (295 men and 312 women, mea n age 45.6±14.0 years) into our cross-sectional study. Lp(a) concentrations correlated inversely with TG, AIP, insulin, HOMA, C-peptide, BMI, waist circumference, and number of MS components (p<0.01 for all). Subjects with MS had significantly lower Lp(a) concentrations in comparison with those without the presence of this phenotype (p<0.0001). Serum concentrations of Lp(a) in the lower (1th 3rd) quartiles of insulin and HOMA were significantly higher than in the 4 th quartile of these insulin resistance markers (p<0.001). Odds ratios of having increased markers of IR (TG, HOMA) and MS in top quartile of Lp(a) also indicate inverse association of Lp(a) with IR. The results of our study support an inverse association of Lp(a) levels with IR and MS that precedes overt T2DM diagnosis., H. Vaverková, D. Karásek, M. Halenka, L. Cibíčková, V. Kubíčková., and Obsahuje bibliografii
In experimental and human diabetes mellitus, evidence for an impaired function of the vascular endothelium has been found and has been suggested to contribute to the development of vascular complications in this disease. The aim of the study was to evaluate possible regional hemodynamic in vivo differences between healthy and diabetic rats which would involve nitric oxide (NO). Central hemodynamics and regional blood flow (RBF) were studied using radioactive microspheres in early streptozotocin (STZ)-diabetic rats and compared to findings in healthy control animals. This method provides a possibility to study the total blood flow and vascular resistance (VR) in several different organs simultaneously. L-NAME iv induced widespread vasoconstriction to a similar extent in both groups. In the masseter muscle of both groups, acetylcholine 2 μg/kg per min, induced a RBF increase, which was abolished by pretreatment with L-NAME, suggesting NO as a mediator of vasodilation. In the heart muscle of both groups, acetylcholine alone was without effect while the combined infusion of acetylcholine and L-arginine induced an L-NAME-sensitive increase in RBF. The vasodilation induced by high-dose acetylcholine (10 μg/kg per min) in the kidney was more pronounced in the STZ-diabetic rats. The results indicate no reduction in basal vasodilating NO-tone in the circulation of early diabetic rats. The sensitivity to vasodilating effects of acetylcholine at the level of small resistance arterioles vary between tissues but was not impaired in the diabetic rats. In the heart muscle the availability of L-arginine was found to limit the vasodilatory effect of acetylcholine in both healthy and diabetic rats. In conclusion, the results indicate a normal action of NO in the investigated tissues of the early STZ-diabetic rat., E. Granstam, S.-O. Granstam., and Obsahuje bibliografii
Vznik a progrese symptomatické diabetické neuropatie (SDN) se váže k hyperglykemii. Při terapii je proto velmi důležitá snaha o zlepšení kompenzace diabetes mellitus. Z tohoto důvodu je třeba kooperace v terapii mezi neurologem a diabetologem. Farmakologická terapie symptomatické senzitivní periferní diabetické neuropatie je svízelná a relativně málo účinná. K symptomatické terapii je užívána celá řada léčivých látek určených primárně k intervenci jiných patologických stavů. V doporučených postupech jsou uváděna antidepresiva, antikonvulziva, opiáty a jejich deriváty. Tato terapie je však zatížena relativně vysokou incidencí nežádoucích účinků, které snižují adherenci pacientů k léčbě. Výborných výsledků dosahuje terapie kyselinou tioktovou., The development and progression of symptomatic diabetic neuropathy (SDN) is linked to hyperglycemia. The effort to improve compensation of diabetes mellitus during therapy is therefore very important. This is where the cooperation between the diabetologist and neurologist within therapy plays an important role. The pharmacological therapy of symptomatic sensitive peripheral diabetic neuropathy is difficult and with a less than satisfactory effect. A variety of active substances is used in symptomatic therapy, primarily designed for intervention in other pathological conditions. The recommended guidelines include antidepressants, anticonvulsants, opiates and their derivatives. However this therapy brings with it a relatively high incidence of adverse effects which detract from patients’ adherence to treatment. Very good results are reached by the therapy with thioctacid., and Denisa Janíčková Žďárská, Milan Kvapil
Arterial sites with low wall shear stress (WSS) are more prone to the development of atherosclerotic plaques, as was observed in carotid arteries in subjects with atherosclerosis risk factors. Type 2 diabetes mellitus (DM), hypertension, hyperlipidemia and other components of the metabolic syndrome, are associated with high risk for symptomatic cerebrovascular disease. It was shown by others that untreated type 2 DM is associated with lower WSS in common carotid arteries. However, the cardiovascular risk of type 2 DM could be modified by therapy. The aim of our study was to test the hypothesis that treated type 2 DM subjects with metabolic syndrome still have lower WSS in common carotid arteries than healthy controls. We enrolled 26 compensated DM subjects with metabolic syndrome, treated by metformin, statins and ACEI for more than 6 months, and 22 aged-comparable healthy controls. Wall shear rate (WSR) was used as a measure of WSS. A linear 3-11 MHz probe was used to measure blood velocity and internal diameter in the common carotid arteries. We compared observed values of WSR adjusted for age by ANCOVA. Wall shear rate was significantly lower in DM group than in control subjects: peak (systolic) values of wall shear rate were 410±130 s-1 vs. 487±111 s-1 (p<0.005). DM subjects had significantly lower WSR, because of both thinner lumen and slower blood flow velocities. Lower WSR was accompanied by higher IMT (0.73±0.12 mm vs. 0.64±0.11 mm, p<0.001). Treated subjects with compensated type 2 DM with metabolic syndrome still have atherogenic hemodynamic profile. These findings might help to understand faster progression of atherosclerosis in diabetic subjects with metabolic syndrome despite up-to-date medication., E. Chytilová ...[et al.]., and Obsahuje seznam literatury
Glucose-dependent insulinotropic peptide (GIP) contributes to incretin effect of insulin secretion which is impaired in Type 2 diabetes mellitus. The aim of this study was to introduce a simple meal test for evaluation of GIP secretion and action and to examine GIP changes in Type 2 diabetic patients. Seventeen Type 2 diabetic patients, 10 obese non-diabetic and 17 nonobese control persons have been examined before and after 30, 60 and 90 min stimulation by meal test. Serum concentrations of insulin, C-peptide and GIP were estimated during the test. Impaired GIP secretion was found in Type 2 diabetic patients as compared with obese non-diabetic and non-obese control persons. The AUCGIP during 90 min of the meal stimulation was significantly lower in diabetic patients than in other two groups (p<0.03). Insulin concentration at 30 min was lower in diabetic than in non-diabetic persons and the GIP action was delayed. The ΔIRI/ΔGIP ratio increased during the test in diabetic patients, whereas it progressively decreased in obese and nonobese control persons. Simple meal test could demonstrate impaired GIP secretion and delayed insulin secretion in Type 2 diabetic patients as compared to obese non-diabetic and nonobese healthy control individuals., J. Škrha., and Obsahuje bibliografii a bibliografické odkazy
b1_Rats with diabetes induced by streptozotocin (STZ) and nicotinamide (NA) are often used in animal studies concerning various aspects of diabetes. In this experimental model, the severity of diabetes is different depending on doses of STZ and NA. Moreover, diabetic changes in rats with STZ-NA-induced diabetes are not fully characte rized. In our present study, metabolic changes and insulin secretion were investigated in rats with diabetes induced by administration of 60 mg of STZ and 90 mg of NA per kg body weight. Four to six weeks after diabetes induction, insulin, glucagon and some metabolic parameters were determined to evaluate the severity of diabetes. Moreover, insulin secretory capacity of pancreatic islets isolated from control and diabetic rats was compared. It was demonstrated that admi nistration of 60 mg of STZ and 90 mg of NA per kg body weight induced relatively mild diabetes, since insulin, glucagon an d other analyzed parameters were only slightly affected in diabetic rats compared with control animals. In vitro studies revealed that insulin secretory response was preserved in pancreatic islets of diabetic rats, however, was lower than in islets of control animals. This effect was observed in the presence of different stimuli. Insulin secretion induced by 6.7 and 16.7 mmol/l glucose was moderately reduced in islets of diabetic rats compared with control islets. In the presence of leucine with glutamine, insulin secretion appeared to be also decreased in islets of rats with STZ-NA-induced diabetes. Insulinotropic action of 6.7 mmol/l glucose with forskolin was also deteriorated in diabetic islets. Moreover, it was demonstrated that at a non-stimulatory glucose, pharmacological depolarization of plasma membrane with a concomit ant activation of protein kinase C evoked significant rise in insulin release in islets of control and diabetic rats., b2_However, in diabetic islets, this effect was attenuated. These results indicate that impairment in insulin secretion in pancreatic islets of rats with mild diabetes induced by STZ and NA result s from both metabolic and nonmetabolic disturbances in these islets., T. Szkudelski, A. Zywert, K. Szkudelska., and Obsahuje bibliografii a bibliografické odkazy