Evidence for a link between glycoxidation and lipoperoxidation in patients with chronic renal failure

The purpose of this study is to examine whether or not there is a relationship between glycoxidation and lipid peroxidation in patients with chronic renal failure.

Dermal samples from 26 living or autopsied subjects were sequentially extracted with NaCl, pepsin, collagenase, and NaOH to obtain four fractions (salt-soluble fraction: SSF; pepsin-soluble fraction: PSF; collagenase-soluble fraction: CSF; and insoluble fraction: ISF). The glycoxidation product was measured by pentosidine-linked fluorescence (ex: 335/em: 385) and the levels of lipid peroxide, malondialdehyde (MDA), were assessed by determining the MDA-linked fluorescence (ex: 390/em: 460) which was further confirmed by HPLC.

In patients undergoing hemodialysis, MDA-linked fluorescence markedly increased in collagen-rich fractions, PSF, CSF, and ISF, while pentosidine-linked fluorescence increased in PSF and CSF, in comparison to the controls and the pre-dialysis patients with CRF. Interestingly, the increase in the lipid peroxides strongly correlated with the level of glycoxidation product in PSF, CSF, and ISF (p < 0.0001 in PSF, CSF; p < 0.01 in ISF). The HPLC data of MDA in the PSF was in good correlation with logistic levels of both MDA- (n = 9, r = 0.738, p = 0.023) and pentosidine-linked fluorescence (n = 9, r = 0.721, p = 0.028). In contrast, in SSF, the collagen-poor fraction (collagen content: less than 3% of the total extracted collagen), the data showed a significant increase in the MDA-linked fluorescence only in the pre-dialysis patients with CRF, but not in the HD patients with no correlation with the glycoxidation products.

These findings suggest that both the lipid peroxidation and glycoxidation increased in close relation to each other in the matrix collagen and thus demonstrate a synergetic contribution to the tissue damage observed in patients with CRF