Iwona Baranowicz-Gaszczyk

Toll-like receptor 4 gene polymorphism and early onset of diabetic retinopathy in patients with type 2 diabetes

Toll-like receptor 4 (TLR4) is an important mediator of innate immunity. Type 2 diabetes (DM2) might be associated with changed innate immune response. We investigated whether the polymorphisms in the TLR4 gene are associated with diabetic retinopathy (DR). The study group of 864 patients with DM2 and 420 healthy individuals were genotyped. In the patient group 352 subjects were diagnosed with DR. Out of the remaining 512, 140 had DM2 for > or = 10 years but no DR. In the DM2 group 7.4% of patients were heterozygous for the Asp299Gly polymorphism compared with 6.5% controls. For Thr399Ile polymorphism there were 7.2% heterozygotes vs 6.2% controls. In most cases, the linkage disequilibrium between the minor alleles Gly299 and Ile399 was confirmed. Increased frequency of both heterozygous genotypes was observed in patients with retinopathy (11.2% for the Asp299Gly). The frequency of the G allele was significantly higher in patients with early onset retinopathy (n = 80) vs patients without DR (odds ratio = 5.0, and 95% confidence interval = 2.33-10.71). In contrast, in the entire retinopathy group, the odds ratio for the G allele was 1.88 (95% confidence interval = 0.93-3.79). In the multivariate logistic regression analysis, the G allele of Asp299Gly was an independent risk factor of early onset DR (p < 0.001). In conclusion, our results suggest an association between the Asp299Gly polymorphism of the TLR4 gene and early onset of DR in the DM2 patients. Thus the G allele may be a predictor of increased risk of retinopathy.

TGF-β1 and TSC-22 Gene Polymorphisms and Susceptibility to Microvascular Complications in Type 2 Diabetes

Background/Aim: There is a strong evidence for the involvement of genetic factors in diabetic microvascular complications. The aim of our study was to investigate the role of molecular variants of the TGF-β1 (transforming growth factor beta 1) and the TSC-22 (transforming growth factor beta stimulated clone 22) genes in diabetic nephropathy and diabetic retinopathy in type 2 diabetes. Methods: A case-control study was conducted in 503 patients and 400 healthy subjects. DNA samples were genotyped by polymerase chain reaction and restriction fragment length polymorphism methods. Results: Among the patients, 245 had diabetic nephropathy, 195 had retinopathy, and 168 were free from complications. All subjects were genotyped for T869C and C –509T polymorphisms of the TGF-β1 gene and for –396 polymorphism of the TSC-22 gene. A significantly increased frequency of the CC genotype of the T869C polymorphism was observed in patients with nephropathy and retinopathy (33 and 48%, respectively, vs. 19 and 15%, respectively, in controls and patients free from complications). The frequency of the C allele was also higher (0.58 for nephropathy and 0.64 for retinopathy vs. 0.42 in controls). The G allele of the TSC-22 polymorphism was associated with an increased risk of diabetic nephropathy (frequency 0.15 vs. 0.07 and 0.06, respectively, in patients free from complications and controls). An interaction was observed between the G allele of the TSC-22 polymorphism and the C-allele of the TGF-β polymorphism. Conclusions: Our data suggest the association of TGF-β T869C gene polymorphism with an increased risk of nephropathy and retinopathy in type 2 diabetes patients. It interacts with the TSC-22 gene involved in the TGF-β signaling pathway, promoting the development of diabetic nephropathy.

A Long-Term Study of Dyslipidemia and Dyslipoproteinemia in Stable Post-Renal Transplant Patients

Background. Dyslipidemia is a major risk factor for atherosclerotic disease in renal transplant patients. Methods. The serum levels of lipids and lipoproteins were determined in the same 12 post-renal transplant patients (TX) 10–29 and 73–122 months after transplantation. Thirteen healthy subjects—i.e., without diabetes, endocrine disease, liver disease, active inflammatory disease, glucose intolerance, malignancy, obesity, and urinary protein—were used as a reference group. TX patients had stable renal function. Twelve patients received cyclosporine A and prednisone, six received lovastatin, and one received rapa and prednisone. Lipids and lipoprotein (apo)AI and B were determined using Roche kits. An anti-apoB antibody was used to separate apoB-containing apoCIII and apoE lipoproteins as triglyceride-rich lipoproteins (TRLs) in the non-HDL fraction from apoCIIInonB and apoEnonB in the HDL fraction. Results. In both groups of post-renal transplant patients, a statistically significant increase of TG, TC, and non-HDL-C levels was observed. Moreover, statistically significant changes were shown in total apoCIII and apoCIIInonB, as well as in TG/HDL-C and apoAI/apoCIII ratios, as compared to the reference group. On the other hand, in TX patients 73–122 months after transplantation, significantly higher concentrations of TC, LDL-C, and especially non-HDL-C were observed. It was shown that apoCIII, apoCIIInonB, apoB:CIII, and lipid and lipoprotein ratios as risk factors of atherosclerosis and renal risk factors were higher in these patients 73–122 months after transplantation. Conclusion. TX patients in a long-term study showed that they had disturbed lipoprotein composition, and its consequence was hyperlipidemia, perhaps partly due to the increased use of immunosuppressants and steroids.

The intercellular adhesion molecule-1 (ICAM-1) gene polymorphism K469E in end-stage renal disease patients with cardiovascular disease.

The intercellular adhesion molecule-1 (ICAM-1) mediates interaction of activated endothelial cells with leukocytes. It plays an important role in the pathogenesis of atherosclerosis. A functionally important polymorphism of the ICAM-1 gene, K469E, has been described. We investigated whether this polymorphism influences the risk of CVD in end-stage renal disease (ESRD) patients. The groups of 1016 ESRD patients and 824 healthy individuals were genotyped by PCR and allele specific oligonucleotide technique. The T allele of the K469E polymorphism was significantly more frequent in ESRD CVD+ patients than CVD- and controls (OR 2.26, 95% CI 1.87-2.72 and 1.82, 95% CI 1.55-2.11, respectively). The TT genotype was also more frequent in CVD+ patients (OR 9.90, 95% CI 6.17-15.88 vs. CVD- subgroup). When patients were stratified according to clinical outcome of CVD, there was a tendency towards higher frequencies of the T allele and TT genotype in patients with myocardial infarction (OR for T allele 1, 57, 95% CI 1.12-2.18 vs. patients without MI). In the multivariate regression analysis the carrier status of T allele of K469E was an independent risk factor of susceptibility to CVD. Our data suggest that the ICAM-1 K469E polymorphism is associated with CVD in ESRD patients.

Effect of G(-174)C polymorphism in interleukin-6 gene on cardiovascular disease in type 2 diabetes patients

Interleukin-6 (IL-6) is an important pro-inflammatory cytokine of relevance to cardiovascular diseases. The aim of this case-control study was to evaluate the association between the G(-174)C functional polymorphism in the IL-6 gene and risk of cardiovascular disease (CVD) in type 2 diabetes patients. We examined 1090 patients with T2DM and 612 controls. All subjects were genotyped for the G(-174)C polymorphism by polymerase chain reaction (PCR) and restriction analysis. There were no significant differences in the distribution of genotypes and alleles between T2DM patients and healthy controls. Significantly higher C allele frequency was observed in CVD+ patients compared to CVD- subgroup (53% vs. 32%, p<0.0001). The odds ratio for C allele was 2.4 (95% CI 1.99-2.9, p<0.0001) and for CC genotype 4.55 (95% CI 3.12-6.63, p<0.000). When the distribution of G(-174)C polymorphism was compared in subgroups with different clinical phenotypes of CVD, a significant association of CC genotype with myocardial infarction was observed. Forty eight percent of patients with MI had the CC genotype compared to 22% of patients without MI (p<0.0001). In conclusion, type 2 diabetes patients carrying the C allele of the IL-6 G(-174)C polymorphism have a significantly increased risk of CVD.

Moderate dyslipoproteinemia induced inflammation and remodeling HDL and VLDL particles in post-renal transplant patients

Abstract The aim of this paper was to examine whether moderate dyslipoproteinemia can cause an increase of hsCRP and LPO levels in Tx patients who had received immunosuppressive therapy and were without acute inflammatory diseases. Herein, the lipid levels, hsCRP, LPO, apolipoprotein (apo)B, AI, AII, AIInonB, apoB-containing AII (apoB:AII), apoCIII, apoCIIInonB, apoB:CIII, LCAT level, as well as CETP and PON1 activity were determined. All examined Tx patients had moderate dyslipidemia and slightly increased hsCRP, LPO, apoB:AII and apoCIII levels, but decreased LCAT mass, PON1 activity and lipoprotein ratios. Tx patients with apoAI<150 mg/dl (n=28) had worse lipoprotein profiles than did Tx patients with apoAI>150mg/dl (n=39), but no difference in CETP activity was indicated. Multiple ridge forward regression and Spearman’s correlation test were used. The results of the presented study, show for the first time that higher apoAI/apoB and apoAI/apoCIII ratios induced a decrease of the hsCRP concentration. Moreover, the composition of apoCIIInonB, LDL-C and apoAI brought about an increase of LCAT mass and PON1 activity. In Tx patients with lower concentration of apoAI, an increase of concentration of apoB:AII in VLDL generated a mild oxidation of lipoprotein and an elevated concentration of LPO. However, lower ApoAI/apoB ratio resulted in an increase of PON1 activity and apoB, as well as nonHDL-C levels, and in turn, PON1 activity increased LCAT mass. These disorders rearranged the HDL particle, and, simultaneously, remodeled the VLDL particle. This may prevent antioxidant activity, reverse cholesterol transport and accelerate the rejection of the transplant, as well as bringing about cardiovascular diseases in Tx patients with lower apoAI. Such metabolic pathways can be used as potentially novel targets for pharmacological intervention.