Length polymorphisms of heme oxygenase-1 determine the effect of far-infrared therapy on the function of arteriovenous fistula in hemodialysis patients: a novel physicogenomic study

The objective of this study was to evaluate the interaction between the length polymorphism of the guanosine thymidine repeat [(GT)(n)] in the heme oxygenase-1 (HO-1) gene and far-infrared (FIR) therapy on access flow (Qa) and arteriovenous fistula (AVF) patency in hemodialysis (HD) patients. A total of 280 HD patients were randomized into a control group (n 141) and the FIR group (n 139) who received 40 min of FIR therapy three times weekly for a year during the study period from May 2005 to December 2007. Access flow was measured during HD. The [(GT)(n)] was determined with the definition of long (L) allele as [(GT)(n)] 30 and short (S) allele as [(GT)(n)] 30. The Qa decreased from S/S to S/L and further to the L/L group but increased by FIR therapy with the highest Qa increase in the S/S group. The incidence of AVF malfunction decreased both from the L/L, S/L to S/S group (32.4 versus 17.2 versus 10.9, P 0.007) and from the control group to FIR group (27.5 versus 12.6, P 0.004). Significant associations were found between AVF malfunction and the following factors (hazard ratio, P-value): a past history of AVF malfunction (2.45, P 0.044), FIR therapy (0.369, P 0.03) and L/L genotypes of HO-1 (2.531 versus S/S S/L genotypes). The 1-year unassisted patency decreased from 91.9 and 77.6 in S/S and S/L subgroups with and without FIR therapy to 75.8 and 60 for L/L subgroup with and without FIR therapy, respectively (P 0.001). FIR therapy improves Qa and patency of AVF in HD patients, with the best protective effect in those with S/S genotype of HO-1.