DNA-array of gene variants in venous leg ulcers: Detection of prognostic indicators

Abstract

Wound healing in venous leg ulcer (VLU) is a multi-step process involving complex pathways. Scanty knowledge at molecular level hinders clinical assessment and treatment. Anomalous handling of local iron overload, as well as unbalancing in matrix metalloproteinases (MMPs) and transglutaminase, has a recognized role in VLU establishment. We selected a number of single nucleotide polymorphisms (SNPs) in candidate genes (HFE, FPN1, MMP12, and FXIII) involved in VLU to identify potentially prognostic markers by means of DNA-array technology. The DNA-array-genotyping was assessed in 638 subjects for the following SNPs: HFE (C282Y, H63D), FPN1 (-8CG), MMP12 (-82AG) and FXIII (V34L). Of the subjects, 221 were affected by VLU (171 primary and 50 post-thrombosis), 112 by severe chronic venous disease (CVD) (CEAP, C3-C4), while 305 were matched healthy controls. The HFE and FXIII SNPs had been previously genotyped by conventional polymerase chain reaction (PCR)-methods on the same group of subjects (J Vasc Surg 2005;42:309; J Vasc Surg 2006;44:554; J Vasc Surg 2006;44:815). For the purpose of DNA-array, they were re-genotyped by means of array-techniques resulting in a 100% matching. Intergroup statistical comparisons were performed. In the risk computation, the FPN1 -8GG genotype had an overall CVD risk of 4.3 (95% CI, 1.6-12) and a VLU risk of 5.2 (95% CI, 1.9-15) virtually the same among primary VLU (4.98; 95% CI, 1.82-14.9). The MMP12-82AA genotype had a VLU risk of 1.96 (95% CI, 1.18-3.2) only in primary VLU (P = .01). In the genotype-ulcer size association studies, from a subgroup of 167 cases, we observed a smaller mean ulcer size in the MMP12 GG-genotype compared with the other genotypes (P = .001). Combining the present results with our previous published data on the same population, we suggest them to apply as tentative prognostic indicators in primary CVD. By analyzing simultaneously selected SNPs, it might be possible to glean precious information in predicting VLU onset or in stratifying patients according to their potential to heal. Although significant, our findings must be considered preliminary and the proposed prognostic indicators considered with caution, before ulterior more extensive studies in different populations can eventually confirm the present findings.