A polymorphism within the fructosamine-3-kinase gene is associated with HbA1c Levels and the onset of type 2 diabetes mellitus.

BACKGROUND: Non-enzymatic glycation is a process, which leads to the formation of advanced glycation endproducts. These compounds are involved in the development of diabetic microvascular complications. Fructosamine-3-kinase (FN3K) is an intracellular enzyme that phosphorylates fructosamines resulting in fructosamine-3-phosphate, which subsequently decomposes to inorganic phosphate, 3-deoxyglucasone and the unmodified amine. Recently, the G900C (rs1056534) single nucleotide polymorpism (SNP) of the FN3K gene was found to be associated with the enzyme activity. OBJECTIVE/DESIGN: The aim of the study was to investigate the impact of the SNP on clinical and biochemical features and microvascular complications of type 2 diabetes. PATIENTS: A total of 859 type 2 diabetic subjects and 265 healthy controls were enrolled in the study and were genotyped with PCR-RFLP method. RESULTS: Genotype frequencies were as follows, CC: 5%, GC: 54%, GG: 41% in subjects with type 2 diabetes and CC: 6%, GC: 51%, GG: 43% in the controls. Diabetic subjects with the CC variant had lower HbA (1c) levels compared with the others (CC: 6.48+/-0.05%; GC: 7.66+/-0.09%; GG: 7.68+/-0.09%; p<0.001). Furthermore, in case of the CC allelic variant type 2 diabetes was diagnosed at a later age than in case of GC or GG variants (CC: 56.0+/-1.90 years; GC: 52.0+/-0.62 years; GG: 50.1+/-0.71 years; p<0.05). Logistic regression analysis did not reveal association between CC genotype and diabetic complications, such as diabetic nephropathy, neuropathy and retinopathy (OR=1.036, CI 95% 0.652-1.647, p=0.880; OR=0.985, CI 95% 0.564-1.721 p=0.958; OR=1.213, CI 95% 0.470-3.132, p=0.690, respectively). CONCLUSION: We conclude that the G900C polymorphism associates with the level of HbA (1c) and the onset of the disease, but not with either of the diabetic microvascular complications.

Haplotype analysis of the apolipoprotein A5 gene in patients with the metabolic syndrome.

BACKGROUND AND AIMS: In recent studies, the T-1131C variant of apolipoprotein A5 (APOA5) gene was found to confer a risk for metabolic syndrome (MS). Here we determined four haplotype-tagging polymorphisms (T-1131C, IVS3+G476A, T1259C, and C56G), and studied the distribution of the naturally occurring major haplotype profiles in MS. METHODS AND RESULTS: A total of 343 MS patients and 284 controls were genotyped using PCR-RFLP methods. Both in MS and control groups, we confirmed the already known association of -1131C, IVS3+473A and 1259C minor alleles with elevated triglyceride levels. The prevalence of the APOA5*2 haplotype (the combination of T-1131C, IVS3+G476A and T1259C SNPs) was 13.1% in MS patients, and 4.9% in controls (p<0.001); multiple logistic regression analysis revealed that this haplotype confers risk for the development of MS (OR=2.880; 95% CI: 1.567-5.292; p=0.001). We also observed a gender effect: in males a more prominent degree of susceptibility was found. Contrary to the APOA5*2 haplotype, the prevalence rate of APOA5*4 (determined by the T-1131C SNP alone) did not differ between MS patients and controls. We identified a novel haplotype, designated here as APOA5*5 (1259C allele alone); which appears to be protective against MS. CONCLUSION: Our results refined the role of SNP T-1131C in the development of MS. The susceptibility nature of this SNP is limited to the APOA5*2 haplotype, while in APOA5*4 haplotype it did not confer a risk for the disease. In addition, as our current data suggest, the novel APOA5*5 haplotype can confer protection against MS.

Microalbuminuria in inflammatory bowel diseases using immunoturbidimetry and high-performance liquid chromatography.

BACKGROUND AND STUDY AIMS: To measure urinary albumin excretion using immunoturbidimetry (IT) and high-performance liquid chromatography (HPLC) in inflammatory bowel diseases. PATIENTS AND METHODS: A cross-sectional study was carried out on 60 selected patients with Crohn's disease (CD), 57 with ulcerative colitis (UC) and 22 healthy volunteers, as controls. Urinary albumin excretion was measured by IT and HPLC, and albumin-creatinine ratio was calculated. This ratio was compared in patients with active and inactive CD and UC and in healthy volunteers. RESULTS: Patients with CD and UC had higher albumin-creatinine ratio compared to controls using both IT and HPLC (p < 0.05). We measured higher albumin-creatinine ratio in patients with active compared to inactive CD (p < 0.05). Albuminuria did not correlate with disease duration of CD or UC, but patients with more extended CD according to the Montreal classification had higher HPLC-albumin-creatinine ratio. In CD, we found a significant correlation between HPLC-albumin-creatinine ratio and some inflammatory markers i.e. white blood cells (p < 0.05) and erythrocyte sedimentation rate (p < 0.05). In UC, there was no significant correlation between HPLC-albumin-creatinine ratio and the above markers of systemic inflammation or activity of UC. Albumin-creatinine ratio measured by HPLC was higher in both active and inactive CD and UC groups than albumin-creatinine ratio measured by IT. Using a receiver operating characteristics curve analysis, in case of HPLC-albumin-creatinine ratio cut-off values of the activity of CD were 2.46 mg/mmol for men, 5.30 mg/mmol for women. CONCLUSIONS: HPLC-urinary albumin-creatinine ratio is associated with the clinical and laboratory disease activity indices in CD, but not in UC. Using HPLC we found a more sensitive method compared to IT to measure albuminuria that would be a sensitive activity marker in CD.

Morphology of glomerular hematuria is reproduced in vitro by carbonyl stress.

BACKGROUND: In glomerulonephritides, dysmorphic red blood cells (RBCs) with membrane blebs can be found in the urine; this is referred to as glomerular hematuria. Glomerulonephritides are characterized by increased carbonyl stress and elevated methylglyoxal (MGO) levels. MGO causes oxidative stress and intracellular calcium accumulation. In the present study, we investigated whether the effect of MGO-induced calcium accumulation in RBCs develops through increased oxidative stress. Furthermore, we studied whether MGO can lead to RBC membrane blebbing. METHODS: RBC suspensions from healthy volunteers were incubated with different concentrations of MGO at 37 degrees C. We measured oxidative stress and intracellular calcium level using fluorescent indicators. We determined the frequency of dysmorphic RBCs, and also performed scanning electron microscopy. RESULTS: MGO increased oxidative stress and caused accumulation of calcium in isolated RBCs. These effects could be prevented using antioxidants. In the presence of MGO, RBC membrane blebbing developed. CONCLUSION: According to our findings, MGO causes calcium accumulation through oxidative stress. Carbonyl and oxidative stress may play an important role in the formation of dysmorphic RBCs in glomerular hematuria.

Cigarette smoke-induced alterations in endothelial nitric oxide synthase phosphorylation: role of protein kinase C.

Endothelial nitric oxide synthase (eNOS) is regulated by phosphorylation of Ser(1177) and Thr(495), which affects NO bioavailability. Cigarette smoke disturbs the eNOS-cGMP-NO pathway and causes decreased NO production. Here the authors investigated the acute effects of cigarette smoke on eNOS phosphorylation, focusing on protein kinases (PKs). Endothelial cell culture was concentration- and time-dependently treated first with cigarette smoke buffer (CSB), then with reduced glutathione (GSH) or various PK inhibitors (H-89, LY-294002, Ro-318425, and ruboxistaurin). eNOS, phospho-Ser(1177)-eNOS, phospho-Thr(495)-eNOS, Akt(PKB), and phospho-Akt protein levels were determined by Western blot. CSB increased the phosphorylation of eNOS at Ser(1177) and more at Thr(495) in a concentration- and time-dependent manner (p < .01, p < .05 versus control, respectively) and resulted in the dissociation of the active dimeric form of eNOS (p < .05). GSH decreased the phosphorylation of eNOS at both sites (p < .05 versus CSB without GSH) and prevented the decrease of dimer eNOS level. CSB treatment also decreased the level of phospho-Ser(473)-Akt (p < .05 versus control). Inhibition of PKA by H-89 did not affect CSB-induced phosphorylation, whereas the PKB inhibitor LY-294002 enhanced it at Ser(1117). The PKC blockers Ro-318425 and ruboxistaurin augmented the CSB-induced phosphorylation at Ser(1177) but decreased phosphorylation at Thr(495) (p < .05 versus CSB). Cigarette smoke causes a disruption of the enzymatically active eNOS dimers and shifts the eNOS phosphorylation to an inhibitory state. Both effects might lead to reduced NO bioavailability. The shift of the eNOS phosphorylation pattern to an inhibitory state seems to be independent of the PKA and phosphoinositol 3-kinase (PI3-K)/Akt pathways, whereas PKC appears to play a key role.

Single dose of acetylsalicylic acid in patients with Type 2 diabetes mellitus and/or chronic renal failure ameliorates anaemia by decreasing the rate of neocytolysis.

BACKGROUND: Anaemia in diabetes mellitus (DM) and/or chronic renal failure (CRF) may be caused by a decreased production of erythropoietin (EPO), EPO resistance, and by the lysis of the young circulating red blood cells (neocytolysis) induced by subclinical inflammation and low EPO level. Aims of this study were to detect EPO resistance in patients with DM and/or CRF and to prove, that acetylsalicylic acid (ASA) is able to improve the haemopoietic status by decreasing neocytolysis. METHODS: In a cross-sectional study, three groups of selected patients (patients with DM; patients with DM+CRF; patients with CRF without DM, n=15 each) and a group of controls (non-diabetic, nonazotemic subjects, n = 10) were compared. In the intervention part of the study, the effect of a single dose of 1 gram ASA on neocytolysis was investigated in a subgroup of these patients. RESULTS: Despite the similar EPO level (p = 1.000), all three patient groups had lower haemoglobin and haematocrit than control persons (p < 0.05 in all cases). Patients with DM+CRF had lower haemoglobin than patients with DM or CRF alone (p < 0.05). Single dose of ASA induced a fast increase in serum EPO level, a concomitant rise of the Rtc number and rate, red blood cell count, haematocrit and haemoglobin p < 0.01 for each). These changes were accompanied by a marked decrease in serum lactate dehydrogenase activity (p < 0.01). CONCLUSIONS: DM and CRF may induce erythropoietin resistance. In these patients, ASA treatment increases serum EPO level. The higher EPO level and the anti-inflammatory effect of ASA may decrease neocytolysis.