Binding and growth-inhibitory effect of heparin and oligo-heparin (2kDa) in Balb/c 3T3 cells: lack of effect on PDGF- or serum-induced inositol lipid turnover

Inhibitory effects of glycosaminoglycans on basal and stimulated transforming growth factor-β1 expression in mesangial cells: biochemical and structural considerations

A number of glycosaminoglycan (GAG) species related to heparin, dermatan sulfate (DeS) and chondroitin sulfate were tested for their ability to interfere with the physiological expression and/or pathological overexpression of the TGF-β1 gene. The influence of the molecular weight, molecular weight distribution, degree of sulfation and location of the sulfate groups was examined in an attempt to unveil fine relationships between structure and activity. The nature of the polysaccharide plays a major part, heparins proving able to inhibit both basal and stimulated TGF-β1 gene expression, DeSs being essentially inactive and chondroitin sulfates only inhibiting stimulated TGF-β1 gene expression. Within this frame, the particular physical and chemical properties of some GAGs appear to further modulate TGF-β1 gene response. Judging from our investigation, chondroitin sulfates seem the most promising for potential pharmacological applications in disorders characterized by fibrogenic TGF-β1 overexpression.

The effect of surface functionalization of PLGA nanoparticles by heparin- or chitosan-conjugated Pluronic on tumor targeting

The poly (lactide-co-glycolide) (PLGA)-based nanoparticles, coated by the heparin- or chitosan-Pluronic conjugate, were used to improve a relatively low tumor-targeting efficiency of the bare PLGA nanoparticles. The prepared nanoparticles were in the size range of 100-150nm, and the surface exposure of the functional moiety (heparin or chitosan) was confirmed by negatively or positively increased zeta potential values, respectively. The viability tests for both normal and tumor cells displayed minimal cytotoxicity of the nanoparticles. The stable surface coating, which was evident from no change in the size distribution profiles in spite of the surface charge changes in serum environment, effectively provided the desired functionalized surface that clearly enhanced the in vitro cellular uptake of the nanoparticles for both heparin and chitosan functionalization. The in vivo tumor model study, which was carried out in SCC7 tumor-bearing athymic mice, demonstrated that there was a limited, but positive effect of surface functionalization, more effective for chitosan functionalization. The accumulation of chitosan-functionalized PLGA nanoparticles in tumor was 2.4 folds higher than that of the control, PLGA nanoparticles coated with bare Pluronic, and the accumulation in liver was lower than the control. In the case of heparin functionalization, the mean value was 2.2 folds higher than that of the control, but the accumulation in liver was similar to that of the control. Therefore, the surface-functionalization by the chitosan- or heparin-conjugated Pluronic may be an effective approach for the hydrophobic nanoparticle systems aiming for the enhanced tumor imaging and therapy.

Transdermal delivery of heparin using pulsed current iontophoresis

PURPOSE

In clinical practice heparin has to be administered by injection with obvious disadvantages; thus, transdermal delivery by electrically assisted methods have been studied. In this study we evaluated the efficacy of a Food and Drug Administration-approved pulsed current iontophoresis system in delivering heparin through living rat skin.

METHODS

Fluorescent and radioactive heparin as well as a commercial heparin preparation were delivered through rat skin via a pulsed current iontophoresis system.

RESULTS

Pulsed current iontophoresis allowed fluorescent heparin to cross the stratum corneum localizing in epidermis and dermis. Unfractionated, high-, and low molecular weight fraction pools, obtained by fractionating [35S]-unfractionated heparin on a molecular weight sieve, were then separately tested. Pulsed current iontophoresis elicited the transdermal delivery of low molecular weight heparin, but not that of high molecular weight heparin. Finally, pulsed current iontophoresis of an unfractionated pharmaceutical heparin preparation significantly decreased plasmatic factor Xa activity.

CONCLUSIONS

We hypothesize that this technique could be used to administer low molecular weight heparin in a cost-efficient and safe manner without the need for syringes and needles.