Cationic derivative of polyprenol, a potential component of liposomal drug carriers, does not alter renal function in rats

Potential toxicity of a cationic derivative of polyprenol (APren‐7) with lipofecting activity was examined,especially its influence on renal haemodynamics and function, in order to conduct further investigation of its suitability as a component of liposomal drug carriers. Sprague–Dawley rats received daily injections (0.5 mL, s.c.) of liposomes comprised of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphoethanolamine (DOPE) and APren‐7 (LP); classic liposomes composed of DOPE only (L); water solvent (W). After 4 weeks rats were anaesthetised and a wide spectrum of functional parameters were measured. These included mean arterial blood pressure (MBP), total renal blood flow (RBF), renal cortical, outer and inner medullary blood flow (CBF, OMBF, IMBF, respectively), diuresis, and sodium and solute excretion. Most parameters did not significantly differ between treated and control groups. A lower OMBF/IMBF ratio in liposome‐treated groups (L: 1.0±0.1; LP: 1.1±0.1 vs. W: 1.9±0.3, p<0.05) might be an early sign of renal function impairment, however, since the lowering occurred in both L and LP groups, there was no reason to suspect that APren‐7 had any untoward influence on renal haemodynamics or excretion. The present results did not reveal toxic effects of APren‐7 in experimental rats, indicating that it could be suitable as a component of liposomal drug carriers. Practical applications: Many currently used drugs have severe side effects, which present a serious problem in the treatment of numerous diseases. Searching for compounds augmenting efficacy of drugs to reduce their dosage seems to be a promising strategy. This can be accomplished by facilitating the bioavailability of the drug, e.g. by improving penetration of biological membranes or delivery to the areas distant from the lumen of blood vessels and in particular instances by improving drug stability. The cationic derivative of polyprenol APren‐7 has lipofecting properties. In this study we found APren‐7 to be harmless to the experimental animals. Newly designed liposomal carriers could find application not only in the pharmaceutical and cosmetics industry but also in biological laboratories and in molecular medicine

High Salt Intake Increases Blood Pressure in Normal Rats: Putative Role of 20-HETE and No Evidence on Changes in Renal Vascular Reactivity

UnlabelledBackground/Aims . High salt (HS) intake may elevate blood pressure (BP), also in animals without genetic salt sensitivity. The development of salt-dependent hypertension could be mediated by endogenous vasoactive agents; here we examined the role of vasodilator epoxyeicosatrienoic acids (EETs) and vasoconstrictor 20-hydroxyeicosatetraenoic acid (20-HETE).MethodsIn conscious Wistar rats on HS diet systolic BP (SBP) was examined after chronic elevation of EETs using 4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (c-AUCB), a blocker of soluble epoxide hydrolase, or after inhibition of 20-HETE with 1-aminobenzotriazole (ABT). Thereafter, in acute experiments the responses of renal artery blood flow (Transonic probe) and renal regional perfusion (laser-Doppler) to intrarenal acetylcholine (ACh) or norepinephrine were determined.ResultsHS diet increased urinary 20-HETE excretion. The SBP increase was not reduced by c-AUCB but prevented by ABT until day 5 of HS exposure. Renal vasomotor responses to ACh or norepinephrine were similar on standard and HS diet. ABT but not c-AUCB abolished the responses to ACh. Conclusions . 20-HETE seems to mediate the early-phase HS diet-induced BP increase while EETs are not engaged in the process. Since HS exposure did not alter renal vasodilator responses to Ach, endothelial dysfunction is not a critical factor in the mechanism of salt-induced blood pressure elevation

High Salt Intake Increases Blood Pressure in Normal Rats: Putative Role of 20-HETE and No Evidence on Changes in Renal Vascular Reactivity

Background/Aims. High salt (HS) intake may elevate blood pressure (BP), also in animals without genetic salt sensitivity. The development of salt-dependent hypertension could be mediated by endogenous vasoactive agents; here we examined the role of vasodilator epoxyeicosatrienoic acids (EETs) and vasoconstrictor 20-hydroxyeicosatetraenoic acid (20-HETE). Methods. In conscious Wistar rats on HS diet systolic BP (SBP) was examined after chronic elevation of EETs using 4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (c-AUCB), a blocker of soluble epoxide hydrolase, or after inhibition of 20-HETE with 1-aminobenzotriazole (ABT). Thereafter, in acute experiments the responses of renal artery blood flow (Transonic probe) and renal regional perfusion (laser-Doppler) to intrarenal acetylcholine (ACh) or norepinephrine were determined. Results. HS diet increased urinary 20-HETE excretion. The SBP increase was not reduced by c-AUCB but prevented by ABT until day 5 of HS exposure. Renal vasomotor responses to ACh or norepinephrine were similar on standard and HS diet. ABT but not c-AUCB abolished the responses to ACh. Conclusions. 20-HETE seems to mediate the early-phase HS diet-induced BP increase while EETs are not engaged in the process. Since HS exposure did not alter renal vasodilator responses to Ach, endothelial dysfunction is not a critical factor in the mechanism of salt-induced blood pressure elevation