This is in agreement with previous reports of the functional effects of this polymorphism on vascular function in T2DM. Subsequently, we found that three polymorphisms, which form the first haplotype block, were also associated with biomarker plasma vWF concentration, which clearly confirms the functional importance of the GCH1 gene variability in the regulation of vascular function in T2DM.
The major mechanism through which the GCH1 gene could affect endothelial function is eNOS uncoupling, which is directly linked to oxidative stress. Four polymorphisms, three constituting the first haplotype block and one from the second haplotype block, are associated with MDA plasma concentration. Moreover, the first haplotype block was even more strongly associated with this variable than any of the analyzed SNPs.This finding suggests that the first haplotype block may contain a non-genotyped polymorphism affecting MDA concentration. Therefore, this would be a stronger association than any of the polymorphisms previously genotyped by our group. An alternative explanation to this finding could be an epigenetic interaction between studied polymorphisms or other polymorphisms in haplotype block 1, modifying the presence of CpG islands in this locus, thereby affecting methylation pattern and expression of GCH1. Such a possibility was demonstrated at other loci. In the case of vWF, association of the first haplotype block with this variable was less significant than with individual SNPs. We also tested whether associations defined in this study could have been confounded by clinical factors. The only clinical variable associated with the outcome variables of MDA and vWF concentrations, was the current smoking status. However, further statistical analysis has shown that the association of SNPs with outcome variables was not confounded by smoking, renal dysfunction, or diabetes duration.
The recently published data comparing urine cytology and other biomarker tests, such as NMP22 and UroVysion FISH indicate high specificity and low sensitivity of cytology. Although cytology is quite specific and sensitive for a high grade variant of urothelial carcinoma, it is considered to be inefficient for the detection of low grade urothelial tumors. By comparing the performance of our proteomic diagnostic formula with cytology we show that proteomics may perform equally well in both high grade and low grade urothelial carcinomas. Therefore, combining proteomic profiling with other diagnostic modalities including cytology may improve the detection of especially low grade urothelial tumors. Unsupervised clustering using all 473 proteins identified clinically distinct subsets of bladder cancer corresponding to indolent and aggressive variants of the disease. In general, the proteomic profiles from voided urine sediments of patients with bladder cancer that clustered with benign controls were indicative of a better prognosis, with longer metastasis-free and disease-free survival, than samples from patients with bladder cancer that formed a distinct cluster. Our study of proteomic expression profiles concerns 473 anonymous protein peaks and 41 of them were used to construct a classification rule. The true nature of these peaks is unknown but as evidenced by prior studies the proteomic profiling of body fluids.