Heparin protection against Fe²⁺‐and Cu²⁺‐mediated oxidation of liposomes

Abstract

Heparin (HE) exhibited a protective effect on liposome peroxidation induced by Fe 2+ and Cu 2+, decreasing the formation of both conjugated dienes and thiobarbituric acid reactive substances (TBARS) in a dose-dependent manner. The antioxidant activity was more relevant in the oxidizing system employing Fe 2+ and H202 and generating the highly reactive "OH radical. The analysis of liposome size distribution by quasielastic laser light scattering showed that: (1) the native structure of the particles was completely lost after exposure to Fenton reagent; (2) the presence of HE in the reaction mixture completely prevented the peroxidative damage on liposomes. Thus, HE acts as an antioxidant factor on membrane lipid bllayer. This suggests that HE, released from mast-cell granules during inflammatory processes, might locally protect the cell membrane from the oxidative injuries.

Dual effect of heparin on Fe2+-induced cardiolipin peroxidation: implications for peroxidation of cytochrome c oxidase bound cardiolipin

“…These results are similar to those when heparin was added to Fe 2+ or Cu 2+ initiated peroxidation of liposomes formed from phosphatidylcholine [45]. The rate of Fe 2+ oxidation is extremely low in liposomal suspensions and is not affected by the absence or presence of heparin (Figure 2, panel a ).…”

“…The ability of heparin to inhibit the Fe 2+ initiated peroxidation of linolenic acid was first demonstrated by Ross et al [53]. Albertini, R. et al have shown that heparin inhibits Fe 2+ or Cu 2+ initiated peroxidation of phosphatidylcholine liposomes [45]. On the basis of liposome size and the presence or absence of heparin, the authors concluded that heparin interacts with phospholipids to make them less susceptible to lipid peroxidation [45].…”

Periodontal Disease Mechanisms: Reactive oxygen species: a potential role in the pathogenesis of periodontal diseases

“…Another possibility is that the sulphated glycosaminoglycans actually bind ؒ OH-promoting iron and copper ions via their sulphate groups, thereby preventing these ions from enhancing ؒ OH production and glycosaminoglycan chain degradation (Grant et al, 1992a(Grant et al, , 1992bWilliamson et al, 1992). Indeed, numerous studies now recognise heparin and other sulphated glycosaminoglycans as potent antioxidants (Albertini et al, 1995(Albertini et al, , 1996a(Albertini et al, , 1996b(Albertini et al, , 1997Grant et al, 1996). The opposite is true for hyaluronan and heparin exposed to NO ؒ , with heparin being more susceptible to degradation than hyaluronan, since the amino groups of Nacetylglucosamine residues in hyaluronan are blocked by N-acetyl groups, rendering these regions resistant to NO ؒ breakdown.…”

Heparin and Heparin-Derivatives in Post-Subarachnoid Hemorrhage Brain Injury: A Multimodal Therapy for a Multimodal Disease

“…Thioredoxin reductase, another enzyme thought protective in oxidative brain injury [ 130 , 131 ], also demonstrates high affinity binding to heparin [ 132 ], although the significance of this interaction is unclear. Several in vitro studies demonstrate direct antioxidant actions of the heparin molecule itself independent of any associated co-enzyme [ 133 , 134 ]. Taken together, these findings suggest that heparin may ameliorate the oxidative injury generated following aSAH.…”