Intracellular magnesium in elderly patients with heart failure: Effects of diabetes and renal dysfunction

Hypomagnesemia is frequent in diabetes mellitus (DM), while renal dysfunction (RD) may be associated with hypermagnesemia. Severe cardiac arrhythmias and other adverse clinical manifestations are frequent in heart failure (HF), in DM and in RD. Depletion of intracellular magnesium (icMg), which may coexist with normal serum Mg, might contribute to these deleterious effects. However, icMg content in normomagnesemic HF patients with RD or DM has not been studied. We assessed total icMg in peripheral blood mononuclear cells (PBMC) from 80 normomagnesemic furosemide-treated HF patients who were divided as follows: subgroups A (DM), B (RD), C (DM and RD), and D (free of DM or RD). PBMC from 18 healthy volunteers served as controls. IcMg content (μg/mg cell protein) in HF was lower compared to controls (1.68±0.2 vs. 2.4±0.39, p<0.001). In the entire HF group, a significant inverse correlation was evident between icMg and serum creatinine (r=−0.37) and daily furosemide dosages (r=−0.121). IcMg in the HF subgroups A, B, C, and D was 1.79±0.23, 1.57±0.23, 1.61±0.25, and 1.79±0.39, respectively (p=0.04 between A and B, p=0.08 between B and D, and non-significant in the remaining comparisons). Serum Mg, potassium, calcium, furosemide dosages and left ventricular ejection fraction were comparable in all subgroups. In conclusion, icMg depletion was demonstrable in PBMC, which may be responsible for some of the adverse clinical manifestations in HF patients. In particular, icMg depletion in RD might contribute to cardiac arrhythmias in this patient group. Mg supplementation to normomagnesemic HF patients might therefore prove beneficial.     

Thyroid volume as measured by ultrasonography in patients With type 1 diabetes mellitus without thyroid dysfunction.

The aim of this cross-sectional study was to assess and compare thyroid volume and its derminants in a cohort of type 1 diabetes mellitus (DM1) and compare the results to a healthy control group. We studied 65 DM1 patients treated with an intensive insulin regimen and 65 matched controls. In all participants we evaluated weight, height, BMI, waist-hip ratio, body surface area and body composition variables determined by using a bioelectrical impedance analyser. Thyroid size was estimated by ultrasonography. We determined basal TSH, anti-thyroid antibodies and urinary iodine excretion. Body weight, height, BMI and body surface area were similar in DM1 patients and in controls. Fat-free mass was higher in both male and female DM1 patients than in controls (64.4 +/- 6.9 vs. 60.4 +/- 8.2 kg, p=0.03 and 48.3 +/- 5.7 vs. 45.4 +/- 6, p=0.04, respectively), and fat mass was lower in male DM1 patients than in controls (9.7 +/- 7 vs. 14.2 +/- 8.1 kg, p=0.01). Thyroid volume was greater in both male and female DM1 patients than in controls (11.12 +/- 2.87 vs. 9.63 +/- 2.27 ml, p=0.0001 and 9.5 +/- 2.3 vs. 7.7 +/- 2 ml, p=0.002, respectively). Urinary iodine excretion was similar in the two groups. In both DM1 patients and controls, thyroid volume correlated with weight, height, BMI, waist-hip ratio, body surface area, fat-free mass and the multivariate linear regression analysis with thyroid volume as the dependent variable showed that fat-free mass in either group was the only significant determinant of thyroid volume. We conclude that DM1 patients had larger thyroid volume compared with healthy controls with similar anthropometry; body composition is different in DM1 patients and that the anthropometric and body composition variables, especially fat-free mass and body surface area, predict thyroid volume either in DM1 patients or in healthy controls.     

Impaired cerebral vasoreactivity in type 2 diabetes mellitus

The aim of our study was to assess cerebral vasoreactivity (CVR) in type 2 diabetes mellitus (DM2) and factors which may influence on it. According to previous studies, evaluating CVR in DM2 on the similar way, the results were dubious. For the evaluation CVR we used breath holding index (BHI) and transcranial Doppler ultrasound (TCD) in 50 patients with DM2 and 50 sex- and age-matched healthy controls. We observed epidemiologic and clinic data, other vascular risk factors and laboratory parameters. We found statistically significant difference in BHI between patients with DM2 (BHI = 0.69 +/- 0.31) and age- and sex-matched healthy controls (BHI = 1.33+/-0.28) (p < 0.05 ). Because of a significant correlation between BHI and age (p < 0.001) in healthy controls we made an adjustment of BHI for age before further analyses (BHIadj). In DM2 group we found a significant correlation between BHIadj and age (p = 0.0004), fasting glycemia (p = 0.04), and albuminuria (p = 0.04) (creatinine clearance in multivariate analysis (p = 0.007)). Our study has shown that CVR is impaired in DM2 patients and that it's severity was associated with age, fasting glycemia and renal function. Functional TCD is a very good screening method for detection and monitoring of cerebral microangiopathic changes in DM2 patients.     

Serum IL-18 levels in patients with type 1 diabetes: relations to metabolic control and microvascular complications

The study was designed to examine serum IL-18 level and its relation to metabolic control parameters and microvascular complications in type 1 diabetes mellitus (DM). Sixty two patients with type 1 DM and 30 healthy individuals were enrolled in the study. Serum IL-18 levels of patients with type 1 DM were significantly increased compared to controls (293.4+/-133.4 vs 211.2+/-63.9 pg/ml, P=0.003). Patients with poor glycemic control had higher levels of IL-18 than patients with well glycemic control (329.9+/-141.0 vs 226.3+/-89.6 pg/ml, P=0.02). There was no significant difference between the serum IL-18 levels of patients with microvascular complications and those of patients without microvascular complications (307.6+/-127.6 vs 293.2+/-145.6 pg/ml, P>0.05). IL-18 correlated positively with HbA(1c) (r=0.32, P=0.01) and postprandial blood glucose (PPBG) (r=0.26, P=0.02); and negatively with HDL-cholesterol (HDL-C) (r=-0.38, P=0.007). By linear regression analysis, PPBG was determined as the most explanatory parameter for the alterations in serum IL-18 levels (P=0.02). High levels of IL-18 in patients with type 1 DM is related to short and long term glycemic control and HDL-C levels but not to microvascular complications.     

Lower wall shear rate of the common carotid artery in treated type 2 diabetes mellitus with metabolic syndrome

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.     

Relation of leptin and tumor necrosis factor alpha to body weight changes in patients with pulmonary tuberculosis

In this study we investigated whether leptin and TNFalpha levels change with improvement in body weight with antituberculotic therapy in active tuberculosis patients. 30 patients (8 females and 22 males) with active pulmonary tuberculosis formed the patient group, and 25 sex- and age-matched healthy subjects (8 females and 17 males) served as the control group. Body weight, body mass index (BMI) and serum leptin and plasma TNFalpha levels are measured before and in the sixth month of therapy in all patients. Before the initiation of therapy, BMI of the patients was significantly lower than BMI of the controls (20.2 +/- 1.6 vs. 25.2 +/- 2.7 kg/m(2), respectively; p < 0.05). After treatment, BMI of the patients increased significantly to 21.4 +/- 1.9 kg/m(2) (p < 0.05), but was still lower than that of the controls (p < 0.05). Pretreatment serum leptin (4.5 +/- 0.9 vs. 2.1 +/- 0.2 ng/ml, respectively; p < 0.05) and plasma TNFalpha (27.9 +/- 3.4 vs. 23.9 +/- 3.0 pg/ml, respectively; p < 0.05) levels of the patients were significantly higher than those of the controls. After treatment, serum leptin levels increased to 6.7 +/- 2.2 ng/ml, but this rise was not statistically significant (p > 0.05). Treatment did not result in any significant change in TNFalpha levels, either. Delta leptin was highly related to Delta BMI in patients with tuberculosis (r = 0.68, p = 0.02). In the pretreatment period, there was a significant correlation between leptin and TNFalpha levels in the whole patient group (r = 0.78, p < 0.001), and in female (r = 0.74, p < 0.001) and male patients separately (r = 0.74, p = 0.035). In conclusion, leptin and TNFalpha may be responsible for the weight loss in pulmonary tuberculosis patients, but their levels do not change with improvement in body weight with antituberculotic treatment.     

Lipopolysaccharide activates an innate immune system response in human adipose tissue in obesity and type 2 diabetes

Type 2 diabetes (T2DM) is associated with chronic low-grade inflammation. Adipose tissue (AT) may represent an important site of inflammation. 3T3-L1 studies have demonstrated that lipopolysaccharide (LPS) activates toll-like receptors (TLRs) to cause inflammation. For this study, we 1) examined activation of TLRs and adipocytokines by LPS in human abdominal subcutaneous (AbdSc) adipocytes, 2) examined blockade of NF-kappaB in human AbdSc adipocytes, 3) examined the innate immune pathway in AbdSc AT from lean, obese, and T2DM subjects, and 4) examined the association of circulating LPS in T2DM subjects. The findings showed that LPS increased TLR-2 protein expression twofold (P<0.05). Treatment of AbdSc adipocytes with LPS caused a significant increase in TNF-alpha and IL-6 secretion (IL-6, Control: 2.7+/-0.5 vs. LPS: 4.8+/-0.3 ng/ml; P<0.001; TNF-alpha, Control: 1.0+/-0.83 vs. LPS: 32.8+/-6.23 pg/ml; P<0.001). NF-kappaB inhibitor reduced IL-6 in AbdSc adipocytes (Control: 2.7+/-0.5 vs. NF-kappaB inhibitor: 2.1+/-0.4 ng/ml; P<0.001). AbdSc AT protein expression for TLR-2, MyD88, TRAF6, and NF-kappaB was increased in T2DM patients (P<0.05), and TLR-2, TRAF-6, and NF-kappaB were increased in LPS-treated adipocytes (P<0.05). Circulating LPS was 76% higher in T2DM subjects compared with matched controls. LPS correlated with insulin in controls (r=0.678, P<0.0001). Rosiglitazone (RSG) significantly reduced both fasting serum insulin levels (reduced by 51%, P=0.0395) and serum LPS (reduced by 35%, P=0.0139) in a subgroup of previously untreated T2DM patients. In summary, our results suggest that T2DM is associated with increased endotoxemia, with AT able to initiate an innate immune response. Thus, increased adiposity may increase proinflammatory cytokines and therefore contribute to the pathogenic risk of T2DM.     

The effect of antioxidant treatment and NOS inhibition on the incidence of ischemia-induced arrhythmias in the diabetic rat heart

Contrary to clinical trials, experimental studies revealed that diabetes mellitus (DM) may initiate, besides increased myocardial vulnerability to ischemia-reperfusion injury (I/R) and pro/antioxidant dysbalance, development of adaptation leading to an enhanced tolerance to I/R. The aims were to characterize 1) susceptibility to ischemia-induced ventricular arrhythmias in the diabetic rat heart 2) its response to antioxidant N-acetylcysteine (NAC) and a NOS inhibitor L-NAME, and 3) the effect of DM on endogenous antioxidant systems. Seven days after streptozotocin injection (65 mg/kg, i.p.), Langendorff-perfused control (C) and DM hearts were subjected to 30-min occlusion of the LAD coronary artery with or without prior 15-min treatment with L-NAME (100 microM) or NAC (4 mM). Total number of ventricular premature beats (VPB), as well the total duration of ventricular tachycardia (VT) were reduced in the DM group (from 533+/-58 and 37.9+/-10.2 s to 224.3+/-52.6 and 19+/-13.5 s; P<0.05). In contrast to the antiarrhythmic effects of L-NAME and NAC in controls group (VPB 290+/-56 and 74+/-36, respectively; P<0.01 vs. control hearts), application of both drugs in the diabetics did not modify arrhythmogenesis (L-NAME: VPB 345+/-136, VT 25+/-13 s; NAC: VPB 207+/-50, VT 12+/-3.9 s; P>0.05 vs non-treated diabetic hearts). Diabetic state was associated with significantly elevated levels of CoQ10 and CoQ9 (19.6+/-0.8 and 217.3+/-9.5 vs. 17.4+/- 0.5 and 185.0+/-5.0 nmol/g, respectively, in controls; P<0.05), as well as alpha-tocopherol (38.6+/-0.7 vs. 31.5+/-2.1 nmol/g in controls; P<0.01) in the myocardial tissue. It is concluded that early period of DM is associated with enhanced resistance to ischemia-induced arrhythmias. Diabetes mellitus might induce adaptive processes in the myocardium leading to lower susceptibility to antioxidant and L-NAME treatment.     

Serum concentrations of fibroblast growth factor 19 in patients with obesity and type 2 diabetes mellitus: the influence of acute hyperinsulinemia, very-low calorie diet and PPAR-α agonist treatment

The aim of our study was to measure serum concentrations of fibroblast growth factor 19 (FGF-19) in patients with obesity (OB), obesity and type 2 diabetes mellitus (T2DM) and healthy subjects (C) at baseline and after selected interventions. We measured serum FGF-19 levels and other biochemical and hormonal parameters in 29 OB and 19 T2DM females and 30 sex- and age-matched control subjects. The interventions were acute hyperinsulinemia during isoglycemic-hyperinsulinemic clamp (n=11 for T2DM and 10 for C), very-low calorie diet (VLCD, n=12 for OB) and 3 months treatment with PPAR-alpha agonist fenofibrate (n=11 for T2DM). Baseline serum FGF-19 levels were significantly lower in OB relative to C group (132.1+/-12.7 vs. 202.2+/-16.7 pg/ml, p<0.05), while no significant difference was observed between T2DM and OB or control group. Acute hyperinsulinemia tended to decrease FGF-19 levels in both healthy and T2DM subjects. Three weeks of VLCD in OB group had no significant effect on FGF-19, whereas three months of fenofibrate treatment markedly reduced FGF-19 levels in T2DM patients (194.58+/-26.2 vs. 107.47+/-25.0 pg/ml, p<0.05). We conclude that FGF-19 levels in our study were at least partially dependent upon nutritional status, but were not related to parameters of glucose metabolism or insulin sensitivity.     

Lysophosphatidylcholine molecular species in low density lipoprotein of type 2 diabetes.

To reveal the importance of lysoposphatidylcholine (LPC) in patients with Type 2 diabetes (DM), LPC in low density lipoprotein (LDL) was determined by high performance liquid chromatography in 38 patients with Type 2 DM and 31 age and sex-matched non-diabetic controls. Stearoyl LPC (SLPC) and palmitoyl LPC (PLPC) were detected in LDL. The contents of both LPCs per gram protein in LDL were increased in diabetic patients compared with the non-diabetics (1.99+/-0.94mg SLPC and 3.02+/-1.81 mg PLPC vs 1.47+/-0.57 mg SLPC and 2.30+/-0.83 mg PLPC, mean +/- SD, p < 0.01 and p < 0.05, respectively). PLPC showed a weak correlation with the levels of fasting plasma glucose (FPG) and HbA1c (r=0.27 and r=0.33, p < 0.05 and p < 0.01, respectively). The diabetic patients with macroangiopathy showed higher levels of PLPC per gram protein compared to those without macroangiopathy (4.60+/-2.61 mg vs 2.53+/1.15 mg, respectively, p < 0.05). The LPC molecular species may participate in the atherogenicity of LDL in patients with Type 2 diabetes.     

Advanced glycation end-products and advanced oxidation protein products in patients with diabetes mellitus

Accelerated glycoxidation takes part in the development of diabetic complications. We determined advanced glycation end-products (AGEs) and advanced oxidation protein products (AOPP) in the sera of 52 patients with diabetes mellitus (DM) - 18 with DM Type 1 and 34 with DM Type 2 and examined their relationship to the compensation of the disease. AGEs were estimated spectrofluorimetrically (350 nm/440 nm) whereas AOPP were determined spectro-photometrically (340 nm). AGEs were elevated only in DM Type 2 (DM2 5.11+/-1.15 x 10(3) AU/g vs controls 4.08+/-0.71 x 10(3) AU/g, p<0.001, vs DM1 4.14+/-0.86 x 10(3) AU/g, p<0.005, DM1 vs controls were not significant). AOPP were elevated significantly in both types of DM with higher levels in DM Type 2 (DM2 157.50+/-75.15 micromol/l vs healthy subjects 79.80+/-23.72 micromol/l, p<0.001, vs DM1 97.50+/-30.91 micromol/l, p<0.005, DM1 vs controls p<0.05). There was a tight correlation between AGEs and AOPP in both types of DM (DM1 r=0.75, DM2 r=0.47 (p<0.05)) and both AGEs and AOPP correlated with triglycerides. In DM Type 1 only, AGEs correlated with HbA1c r=0.47 (p<0.05) and with blood glucose. Slight but not significant differences in AGEs and AOPP levels were observed in patients with or without diabetic complications. Oxidative stress is increased in both types of DM, more in Type 2 where it contributes to the formation of glycoxidation products.     

The characterization of central neuromediation in rats fed with magnesium-deprived diet before and after magnesium replenishment

Magnesium (Mg) has been proposed to take part in biochemical dysregulation contributing to psychiatric disorders. The aims of this study was to estimate acute behavioural responses to clonidine (0.1 mg/kg i.p.), d-amphetamine (5 mg/kg, i.p), arecoline (15 mg/kg i.p), nicotine (6 mg/kg i.p.), apomorphine (1.5 mg/kg i.p.) and L-5-hydroxytryptophan (300 mg/kg i.p.) in rats fed with Mg-deprivated diet for 49 days and then treated with organic and inorganic Mg salts (50 mg Mg per kg) ether alone or in combination with pyridoxine (5 mg vitamin B6 per kg). In our study Mg-deficient rats were more sensitive to d-amphetamine-induced motor stereotypes compared with control rats; time of onset of the stereotypies insignificantly decreased by 14.89% and duration of the stereotypies significantly increased by 19.44% (320.36 +/- 19.90 vs. 268.23 +/- 8.17 minutes; p = 0.043). Mg deficiency did not modulate sensitivity to nicotine-induced seizure. The time between nicotine injection and emergence of clonic seizure (seizure latency) in the controls and Mg-deficient rats were 0.80 +/- 0.26 and 0.96 +/- 0.21 minutes respectively. Duration of the seizures in the controls and Mg-deficient rats were 64.93 +/- 7.20 and 79.32 +/- 8.13 minutes. In our study, Mg deficiency did not affect on clonidine- and apomorphine-induced hypothermia. Clonidine produced similar decreases in rectal temperature in controls and Mg-deficient group. In experiments using apomorphine, values of hypothermia were similar to those observed with clonidine. Mg deficiency antagonized 5-hydroxytryptophan-induced head-twitch response. The number of head twitches produced by 5-hydroxytryptophan was significantly (p = 0.49) decreased: twofold in magnesium-deficient rats (1.23 +/- 0.44 per minute) as compared with controls (2.42 +/- 0.52 per minute). Arecoline-induced tremor was comparably less expressed in Mg-deficient rats than in controls. The time between arecoline injection and time of onset of the tremor in the controls and Mg-deficient rats were 92.75 +/- 19.35 and 245.17 +/- 121.86 seconds respectively (p < or = 0.035). Duration of the tremors in the controls and Mg-deficient rats were 1175.58 +/- 127.87 and 703.83 +/- 89.33 seconds (p = 0.015). Magnesium salts (Mg chloride, Mg L-aspartate alone and in combination with B6) were administered through gastric tube during twenty days up to complete compensation oferythrocyte and plasma Mg levels in all experimental groups. In our study administration of Mg salts resulted in normalization of acute behavioural responses in Mg-deficient rats to d-amphetamine, arecoline, and L-5-hydroxytryptophan. Behavioural responses in rats treated with both Mg chloride and Mg L-aspartate in combinations with B6 were comparable with those observed in MagneB6 treatment.     

Elevated white blood cell count, CRP and fibrinogen levels are not associated with increased anti-endothelial and anti-ox-LDL antibody, MCP-1, and RANTES levels in early onset occlusive carotid artery disease

BACKGROUND: Inflammatory processes have importance in atherosclerosis. We evaluated if subjects below 55 years of age with occlusive carotid artery disease have higher serum levels of antibodies against oxidized LDL and endothelial cells and the chemokines MCP-1 and RANTES than age matched subjects without atherosclerosis. METHODS AND RESULTS: Sixty patients with occlusive carotid artery disease (stenosis or occlusion) and 30 age-matched controls participated in the study. We measured the degree of carotid artery stenosis and intima-media thickness (IMT) by duplex ultrasound. White blood cell count (WBC), C-reactive protein (CRP), and fibrinogen levels were significantly higher in patients (means+/-SD: 7.5+/-1.8 vs. 6.1+/-1.1 G/L, p<0.001; 7.7+/-20.7 vs. 2.5+/-1.9 mg/L, p=0.015; and 3.7+/-0.9 vs. 3.1+/-0.5 g/L, p<0.001, respectively). Antibody levels against oxidized LDL and endothelial cells (21.1+/-22.9 and 19.9+/-15.3 EU/mL, p=0.6; and 19+/-15 vs. 20+/-9 U/mL, p=0.07) and RANTES and MCP-1 levels (72.4+/-32.3 vs. 73.8+/-27.3 ng/mL, p=0.7; and 468+/-1041 vs. 318+/-131 pg/mL, p=0.7) did not differ significantly between patients and controls and did not correlate with IMT. CONCLUSIONS: Higher levels of WBC, CRP, and fibrinogen suggest an ongoing inflammation in early-onset carotid atherosclerosis, but increased IMT is not associated by the elevation of serum levels of chemokines and antibodies evaluated in this study.     

Mathematical modeling shows exenatide improved beta-cell function in patients with type 2 diabetes treated with metformin or metformin and a sulfonylurea.

The incretin mimetic exenatide improved glycemic control and reduced body weight in patients with type 2 diabetes inadequately controlled with metformin+/-a sulfonylurea. We assessed postprandial beta-cell function by mathematical modeling, independent of confounding effects from differing ambient glucose levels among treatments. Subjects were 63% males, 55+/-10 years, BMI 33+/-6 kg/m2, HbA1C 8.1+/-1.1% (+/- SD) randomized to 5 microg exenatide or placebo twice daily for 4 weeks. Subsequently, one arm remained at 5 microg twice daily, one arm escalated to 10 microg twice daily, and one treatment arm remained on placebo for 26 weeks. Subjects continued metformin+/-a sulfonylurea. A subset with meal tests at baseline and week 30 were analyzed (n=73). Outcome measures were the model-based beta-cell function parameters dose-response relating insulin secretion to glucose concentration, rate sensitivity, and potentiation. Exenatide reduced postprandial glucose excursions. Modeling predicted an upward shift of the beta-cell dose-response. Model-predicted insulin secretion rate at a reference glucose concentration increased 72% (10 microg), increased 40% (5 microg), or decreased 21% (placebo) at week 30 [ p=0.015 (10 microg); p=0.045 (5 microg); vs. placebo]. At week 30, the 2-hour post-meal to basal potentiation factor ratio was increased to 1.53+/-0.10 (10 microg; p=0.0142 vs. placebo) or 1.40+/-0.08 (5 microg; p=0.0402 vs. placebo) compared with 1.15+/-0.06 (placebo). Exenatide caused an upward shift of the beta-cell dose-response and enhanced potentiation of insulin secretion. This model suggests exenatide improved beta-cell function in patients with type 2 diabetes treated with metformin+/-a sulfonylurea.     

Soluble LDL-immune complexes in type 2 diabetes and vascular disease.

BACKGROUND AND AIMS: The oxidative modification of LDL has been shown to affect its clearance and to exert cytotoxic and immunogenic effects. The objective of our study was to analyse markers of LDL oxidation-soluble LDL containing immune complexes (LDL-ICs) in type 2 diabetes with micro- and macrovascular disease. PATIENTS AND METHODS: The study included 69 diabetic patients with coronary artery disease (DM + CAD), 78 non-diabetics with CAD, 47 controls, and 27 diabetics with nephropathy and 36 free from complications. OxLDL antibodies and advanced glycated end-products were measured by ELISA, and LDL-IC apo B content after PEG precipitation. RESULTS: Determination of a broad range of oxLDL antibody activity in all study groups showed no significant differences. In contrast, the content of apo B, a component of the antigen moiety of oxLDL-ICs, was higher in CAD and diabetes (+ CAD) than in LDL-ICs isolated from controls (p < 0.001). LDL-ICs did not differ between patients with CAD + DM and CAD patients free from diabetes. LDL-IC levels in diabetic patients with or without microangiopathy were significantly higher than in healthy volunteers (PEG-apo B 0.278 +/- 0.107 vs. 0.165 +/- 105 g/l, p < 0.002; PEG-IgG 151.7 +/- 76 vs. 115.4 +/- 62 g/l, p < 0.05). However, there was no significant difference in the level of circulating LDL-ICs between the subgroup of diabetic patients with nephropathy/retinopathy and patients free of microvascular disease (Ab-oxLDL 27.7 +/- 10.4 vs. 27.1 +/- 9.3 AU, NS; PEG-apo B 0.324 +/- 0.111 vs. 0.287 +/- 0.124 g/l, NS; PEG-IgG 1.68 +/- 0.68 vs. 1.42 +/- 0.80 g/l, NS). There was a statistically significant positive correlation between AGE content and LDL-ICs (r = 0.35, p < 0.009). A significant but inverse correlation was recorded between triglyceride concentration and level of LDL-ICs in DM + CAD (r = - 0.32, p < 0.016) and CAD patients (r = - 0.35, p < 0.002). A highly significant negative correlation between triglycerides and circulating LDL-ICs (r = - 0.54, p < 0.039) was observed in patients with early nephropathy, but not in those with physiological proteinuria. It is known that at a high triglyceride level in type 2 diabetes, the majority of LDL are small and dense, thus being more susceptible to oxidative modification. This could be a possible mechanism explaining why more LDL-ICs, with a level inversely correlating with triglyceride concentration, are generated in diabetes. CONCLUSION: The increased level of circulating LDL-ICs is a risk factor for the general population, including those with diabetes. Our results suggested the contribution of LDL-ICs to the development of atherosclerosis to probably be more significant than the direct contribution of oxLDLAb itself.     

Low Blood Mononuclear Cell Magnesium Content and Hypocalcemia in Normomagnesemic Patients

Hypomagnesemia can cause hypocalcemia. Because less than 1% of the total body magnesium (Mg) is in extracellular fluids, however, patients may be Mg-deficient despite normal serum Mg concentrations. To determine if hypocalcemia can be seen in patients who have normal serum Mg concentrations but low intracellular Mg, we studied the serum and mononuclear cell Mg contents in 82 alcoholic subjects, 30 of whom had hypocalcemia that could not be explained by other known causes of hypocalcemia. The mononuclear cell Mg content in both hypomagnesemic and normomagnesemic patients with and without hypocalcemia was significantly lower than in normal controls. The serum Mg level did not correlate with the mononuclear cell Mg or serum calcium level, but hypocalcemic patients had a significantly lower mononuclear cell content than normocalcemic patients. Six patients underwent parenteral Mg tolerance testing as an additional measure of Mg deficiency and had increased Mg retention. The serum calcium concentration returned to normal in hypocalcemic patients who were given magnesium intravenously.     

Hyperlipoproteinemia impairs endothelium-dependent vasodilation

Atherogenic lipoproteins can cause endothelial dysfunction in the initial stage of atherogenesis. In our study we examined 134 patients with defined hyperlipoproteinemia (non-HDL cholesterol>4.1 mmol/l or triglycerides>2.5 mmol/l or taking any of lipid lowering drugs)--94 men and 40 women. The subgroup of controls of comparable age contained 54 normolipidemic individuals--30 men and 24 women. Patients with hyperlipoproteinemia revealed significantly lower ability of endothelium-dependent flow-mediated vasodilation (EDV) measured on brachial artery (4.13+/-3.07 vs. 5.41+/-3.82 %; p=0.032) and higher carotid intima media thickness than normolipidemic controls (0.68+/-0.22 vs. 0.58+/-0.15 mm; p=0.005). In regression analysis, EDV correlated significantly with plasma concentrations of oxLDL (p<0.05) HDL-cholesterol (p<0.05), Apo A1 (p<0.05), ATI (p<0.01) and non-HDL cholesterol (p<0.05). Patients with hyperlipoproteinemia showed higher plasma levels of oxLDL (65.77+/-9.54 vs. 56.49+/-7.80 U/l; p=0.015), malondialdehyde (0.89+/-0.09 vs. 0.73+/-0.08 micromol/l; p=0.010) and nitrites/nitrates (20.42+/-4.88 vs. 16.37+/-4.44 micromol/l; p=0.018) indicating possible higher long-term oxidative stress in these patients.     

Energy expenditure, energy intake and prevalence of obesity after therapy for acute lymphoblastic leukemia during childhood

OBJECTIVES: To investigate the prevalence and potential risk factors of obesity after therapy for childhood acute lymphoblastic leukemia (ALL). STUDY DESIGN: 39 ALL patients (age 10.7-20.5 years) who were in first remission for 3.4-14.6 years after standardized treatment with chemotherapy plus cranial irradiation (n = 25) or with chemotherapy alone (n = 14) were examined. After fasting overnight, the following parameters were investigated: body mass index (BMI) of patients and their parents; patients' BMI before ALL therapy; serum free thyroxin, growth hormone-dependent factors, estradiol, testosterone, cortisol, leptin and c-peptide; fat-free mass (bioelectrical impedance); resting metabolic rate (RMR, indirect calorimetry); caloric intake (24-hour recall); and physical activity (questionnaire). RMR data were applied to the fat-free mass and compared with 83 controls. RESULTS: The prevalence of obesity (criterion: BMI > 2 SDS) was significantly (p < 0.05) higher after ALL therapy (38%; irradiated patients 48%, non-irradiated patients 21%) than before therapy (3%). Compared to non-irradiated patients, irradiated patients had significantly lower RMRs (-1.07 +/- 0.24 vs. -0.32 +/- 0.21 SDS; p < 0.05), reduced physical activity levels (1.41 +/- 0.03 vs. 1.52 +/- 0.03; p < 0.05), and lower concentrations of insulin-like growth factor-binding protein-3 (-0.65 +/- 0.17 vs. 0.25 +/- 0.33 SDS; p < 0.05) and of free thyroxin (1.17 +/- 0.06 vs. 1.38 +/- 0.08 ng/dl; p < 0.05). Caloric intake was adequate. CONCLUSIONS: After ALL during childhood, patients face a higher risk of obesity. In the cranially irradiated patients, the likely causes are low physical activity, RMRs and hormonal insufficiency.     

The serum concentration of tumor necrosis factor alpha is not an index of growth-hormone- or obesity-induced insulin resistance

BACKGROUND: The tumor necrosis factor alpha (TNF-alpha) might play a central role in insulin resistance, a frequent correlate of obesity likely contributing to some obesity-associated complications. Adult growth hormone (GH) deficiency syndrome (GHDA) shares with obesity excessive fat mass, hyperlipidemia, increased cardiovascular risk, and insulin resistance. On the other hand, GH has been shown to induce transient deterioration of glucose metabolism and insulin resistance when administered in normal humans and in GHDA patients. No information is presently available on the relationship between serum TNF-alpha levels and insulin sensitivity in GHDA. METHODS: We compared the serum TNF-alpha levels found in 10 GHDA patients before and after a 6-month recombinant human GH therapy (Genotropin), in an insulin resistance prone population of 16 obese (OB) patients and in 38 normal-weight healthy blood donors (controls). The insulin sensitivity was assessed by a euglycemic-hyperinsulinemic glucose clamp in all the GHDA patients and in 10 OB and in 6 control subjects. RESULTS: The serum TNF-alpha levels were not significantly different in OB patients (42.2 +/- 12.81 pg/ml), in GHDA patients at baseline (71.3 +/- 23.97 pg/ml), and in controls (55.3 +/- 14.28 pg/ml). A slight decrease of TNF-alpha values was noted in GHDA patients after 6 months of recombinant human GH treatment (44.5 +/- 20.19 pg/ml; NS vs. baseline). The insulin sensitivity (M) was significantly reduced in OB patients (2.4 +/- 0.30 mg/kg/min) as compared with control subjects (7.5 +/- 0.39 mg/kg/min) and in GHDA patients both at baseline (6.6 +/- 0.6 mg/kg/min) and after recombinant human GH therapy (5.6 +/- 0.7 mg/kg/min). The insulin sensitivity in the GHDA patients, similar to that of controls at baseline, worsened after recombinant human GH treatment (p < 0.05 vs. baseline; p = 0.05 vs. controls). Linear regression analysis showed no correlation between TNF-alpha and M values (see text) in all patient groups. CONCLUSIONS: These data indicate that circulating concentrations of TNF-alpha do not reflect the degree of insulin resistance in obesity and GHDA. They, however, do not exclude that TNF-alpha may induce insulin resistance at tissue level.     

Effects of a combination of recombinant human growth hormone with metformin on glucose metabolism and body composition in patients with metabolic syndrome.

Abdominal obesity and insulin resistance are central findings in metabolic syndrome. Since treatment with recombinant human growth hormone (rhGH) can reduce body fat mass in patients with organic GH deficiency, rhGH therapy may also have favourable effects on patients with metabolic syndrome. However, due to the highly increased risk for type 2 diabetes in these patients, strategies are needed to reduce the antagonistic effect of rhGH against insulin. We conducted a 18-month randomised, double-blind, placebo-controlled study to assess the effect of rhGH in combination with metformin (Met) in patients with metabolic syndrome. 25 obese men (55 +/- 6 years, BMI 33.4 +/- 2.9 kg/m (2)) with mildly elevated fasting plasma glucose (FPG) levels at screening (6.1-8.0 mmol/l) were included. All patients received metformin (850 mg twice daily) either alone or in combination with rhGH (daily dose 9.5 microg/kg body weight). An oGTT was performed at baseline, after 6 weeks, and after 3, 6, 12, and 18 months of therapy. Glucose disposal rate (GDR) was measured by euglycemic hyperinsulinemic clamp at 0 and 18 months and body composition was measured by DEXA every 6 months. In the Met + GH group, IGF-I increased from 146 +/- 56 microg/l to 373 +/- 111 microg/l (mean +/- SD) after 3 months and remained stable after that. BMI did not change significantly in either group during the study. Total body fat decreased by -4.3 +/- 5.4 kg in the Met + GH group and by -2.7 +/- 2.9 kg in the Met + Placebo group (differences between the two groups: p = n. s.). Waist circumference decreased in both groups (Met + GH: 118 +/- 8 cm at baseline, 112 +/- 10 cm after 18 months; Met + Placebo: 114 +/- 7 cm vs. 109 +/- 8 cm; differences between the two groups: p = 0.096). In the Met + GH group, FPG increased significantly after 6 months (5.9 +/- 0.7 vs. 6.7 +/- 0.4 mmol/l; p = 0.005), but subsequently decreased to baseline levels (18 months: 5.8 +/- 0.2 mmol/l). FPG remained stable in the Met + Placebo group until 12 months had elapsed, and then slightly decreased (baseline: 6.2 +/- 0.3, 18 months: 5.5 +/- 0.6 mmol/l, p = 0.02). No significant changes were seen in either group regarding glucose and insulin AUC during oGTT or HbA (1c) levels. GDR at 18 months increased by 20 +/- 39% in Met + GH-group and decreased by -11 +/- 25% in the Met + Placebo group (differences between the two groups: p = 0.07). In conclusion, treatment of patients with metabolic syndrome and elevated FPG levels did not cause sustained negative effects on glucose metabolism or insulin sensitivity if given in combination with metformin. However, since our data did not show significant differences between the two treatment groups with respect to body composition or lipid metabolism, future studies including larger numbers of patients will have to clarify whether the positive effects of rhGH on cardiovascular risk factors that have been shown in patients with GH deficiency are also present in patients with metabolic syndrome, and are additive to the effects of metformin.