Pharmacokinetics of the Urokinase Receptor-Derived Peptide UPARANT After Single and Multiple Doses Administration in Rats.

BACKGROUND AND OBJECTIVES: UPARANT has emerged as a novel therapeutic agent with the potential to treat ocular diseases as assessed by studies in animal models. Since limited information is available on the pharmacokinetics of UPARANT, the aim of this study is to evaluate its pharmacokinetics after single and multiple ascending dose (SAD and MAD) administration in rats. METHODS: Male (n = 27) and female (n = 27) Sprague-Dawley rats were divided into six groups (n = 9/sex/group). UPARANT was administered via subcutaneous injection as single (10, 50 or 100 mg/kg; day 1) and multiple (10, 50 or 100 mg/kg/day; 7 consecutive days; day 7) dosing. Blood samples were collected on day 1 (pre-dose, 0.5, 1, 2, 4, 8 and 24 h post dose) and day 7 (pre-dose, 0.5, 1, 2, 4, 8, 24, 48 and 192 h post dose). The plasma concentration of UPARANT was determined by a validated liquid chromatography mass spectrometry method. RESULTS: The plasma concentration-time profiles of UPARANT were similar in SAD and MAD administration in both male and female rats. The compound reached maximum plasma concentration (Cmax) at 1-2 h with a slow apparent plasma clearance and a moderate apparent volume of distribution. Moreover, SAD administration revealed a non-proportional increase in Cmax and in the area under the plasma concentration-time curve (AUCinf), whereas a dose-proportional increase in AUCinf was shown after MAD administration. Regarding the extent of accumulation, the data suggest negligible accumulation of the compound after multiple administrations. CONCLUSION: The pharmacokinetics of UPARANT were not sex-related, and there was negligible accumulation in plasma after 7 days of treatment. However, the compound exhibited no dose-proportional pharmacokinetics after single and multiple ascending subcutaneous dosing.

Modulation of Stat-1 in Human Macrophages Infected with Different Species of Intracellular Pathogenic Bacteria.

The infection of human macrophages by pathogenic bacteria induces different signaling pathways depending on the type of cellular receptors involved in the microorganism entry and on their mechanism(s) of survival and replication in the host cell. It was reported that Stat proteins play an important role in this process. In the present study, we investigate the changes in Stat-1 activation (phosphorylation in p-tyr701) after uptake of two Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and two Gram-negative bacteria (Salmonella typhimurium and Legionella pneumophila) characterized by their varying abilities to enter, survive, and replicate in human macrophages. Comparing the results obtained with Gram-negative and Gram-positive bacteria, Stat-1 activation in macrophages does not seem to be related to LPS content. The p-tyr701Stat-1 expression levels were found to be independent of the internalized bacterial number and IFN-γ release. On the contrary, Jak/Stat-1 pathway activation only occurs when an active infection has been established in the host macrophage, and it is plausible that the differences in the expression levels of p-tyr701Stat-1 could be due to different survival mechanisms or to differences in bacteria life cycles within macrophages.