Synthesis and functionalization of protease-activated nanoparticles with tissue plasminogen activator peptides as targeting moiety and diagnostic tool for pancreatic cancer

Background: Functionalized nanoparticles (NPs) are one promising tool for detecting specific molecular targets and combine molecular biology and nanotechnology aiming at modern imaging. We aimed at ligand-directed delivery with a suitable target-biomarker to detect early pancreatic ductal adenocarcinoma (PDAC). Promising targets are galectins (Gal), due to their strong expression in and on PDAC-cells and occurrence at early stages in cancer precursor lesions, but not in adjacent normal tissues. Results: Molecular probes (10-29 AA long peptides) derived from human tissue plasminogen activator (t-PA) were selected as binding partners to galectins. Affinity constants between the synthesized t-PA peptides and Gal were determined by microscale thermophoresis. The 29 AA-long t-PA-peptide-1 with a lactose-functionalized serine revealed the strongest binding properties to Gal-1 which was 25-fold higher in comparison with the native t-PA protein and showed additional strong binding to Gal-3 and Gal-4, both also over-expressed in PDAC. t-PA-peptide-1 was selected as vector moiety and linked covalently onto the surface of biodegradable iron oxide nanoparticles (NPs). In particular, CAN-doped maghemite NPs (CAN-Mag), promising as contrast agent for magnetic resonance imaging (MRI), were selected as magnetic core and coated with different biocompatible polymers, such as chitosan (CAN-Mag-Chitosan NPs) or polylactic co glycolic acid (PLGA) obtaining polymeric nanoparticles (CAN-Mag@PNPs), already approved for drug delivery applications. The binding efficacy of t-PA-vectorized NPs determined by exposure to different pancreatic cell lines was up to 90%, as assessed by flow cytometry. The in vivo targeting and imaging efficacy of the vectorized NPs were evaluated by applying murine pancreatic tumor models and assessed by 1.5 T magnetic resonance imaging (MRI). The t-PA-vectorized NPs as well as the protease-activated NPs with outer shell decoration (CAN-Mag@PNPs-PEG-REGAcp-PEG/tPA-pep1Lac) showed clearly detectable drop of subcutaneous and orthotopic tumor staining-intensity indicating a considerable uptake of the injected NPs. Post mortem NP deposition in tumors and organs was confirmed by Fe staining of histopathology tissue sections. Conclusions: The targeted NPs indicate a fast and enhanced deposition of NPs in the murine tumor models. The CAN-Mag@PNPs-PEG-REGAcp-PEG/tPA-pep1Lac interlocking steps strategy of NPs delivery and deposition in pancreatic tumor is promising

THE EFFECTS OF TIME-TO-SURGERY ON MORTALITY IN ELDERLY PATIENTS FOLLOWING HIP FRACTURES

Abstract Introduction: Mortality occurring as a consequence of hip fracture in older patients is very high. Mortality is highest in the first few months after the injury, and this rate is kept at a high level within the first six months postoperatively. Current guidelines indicate that surgery should be performed within 48 hours of injury because early surgery is associated with lower rates of perioperative complications and mortality. Aim: To analyse the effects of time-to-surgery on mortality in elderly patients with hip fracture. Material and methods: The research was conducted at the University Traumatology Clinic in Skopje, where 120 patients with hip fracture of age 65 and above were treated. The age span was 55-95 years, with a mean age of 73.9 ± 9.8 years. The time frame for the research and the follow-up of the patients was 6 months. Inclusion criteria included patients aged above 65 and isolated proximal femur fractures. Survival time for patients after six months was determined with the Kaplan-Meier product-limit method. Statistical significance was evaluated at level of p < 0.05. Results: The mean time from patient admission to surgical intervention was 3.07 ± 1.5 days (range 0-6 days). Hospitalization time averaged 11 ± 4.7 days. We separated our patient population into two groups, one consisting of patients operated in the first two days, the other after two days. The patient death rate in the first group of 25 patients operated in the first 48 hours was a total of 4 patients (16%) after 6 months. The second group, 95 patients operated after 48 hours, showed a significant rise in mortality -32 patients (33.7%). The mean survival time of patients operated within 48 hours is 168.8 days, while the mean survival time of patients operated after 48 hours from their hospital admission was 143.6 days. Conclusion: Delay in surgery is associated with significant increase in mortality. Patients should have their operation as soon as possible after admission to hospital, preferably in the first 48 hours