Inflammatory response toward a Mg-based metallic biomaterial implanted in a rat femur fracture model.

The immune system plays an important role in fracture healing, by modulating the pro-inflammatory and anti-inflammatory responses occurring instantly upon injury. An imbalance in these responses can lead to adverse outcomes, such as non-union of fractures. Implants are used to support and stabilize complex fractures. Biodegradable metallic implants offer the potential to avoid a second surgery for implant removal, unlike non-degradable implants. However, considering our dynamic immune system it is important to conduct in-depth studies on the immune response to these implants in living systems. In this study, we investigated the immune response to Mg and Mg-10Gd in vivo in a rat femur fracture model with external fixation. In vivo imaging using liposomal formulations was used to monitor the fluorescence-related inflammation over time. We combine ex vivo methods with our in vivo study to evaluate and understand the systemic and local effects of the implants on the immune response. We observed no significant local or systemic effects in the Mg-10Gd implanted group compared to the SHAM and Mg implanted groups over time. Our findings suggest that Mg-10Gd is a more compatible implant material than Mg, with no adverse effects observed in the early phase of fracture healing during our 4-week study. STATEMENT OF SIGNIFICANCE: Degradable metallic implants in form of Mg and Mg-10Gd intramedullary pins were assessed in a rat femur fracture model, alongside a non-implanted SHAM group with special respect to the potential to induce an inflammatory response. This pre-clinical study combines innovative non-invasive in vivo imaging techniques associated with multimodal, ex vivo cellular and molecular analytics. The study contributes to the development and evaluation of degradable biometals and their clinical application potential. The study results indicate that Mg-10Gd did not exhibit any significant harmful effects compared to the SHAM and Mg groups.

Maternal microbiota communicates with the fetus through microbiota-derived extracellular vesicles.

BACKGROUND: Reports regarding the presence of bacteria in the fetal environment remain limited and controversial. Recently, extracellular vesicles secreted by the human gut microbiota have emerged as a novel mechanism for host-microbiota interaction. We aimed to investigate the presence of bacterial extracellular vesicles in the fetal environment during healthy pregnancies and determine whether extracellular vesicles derived from the gut microbiota can cross biological barriers to reach the fetus. RESULTS: Bacterial extracellular vesicles were detectable in the amniotic fluid of healthy pregnant women, exhibiting similarities to extracellular vesicles found in the maternal gut microbiota. In pregnant mice, extracellular vesicles derived from human maternal gut microbiota were found to reach the intra-amniotic space. CONCLUSIONS: Our findings reveal maternal microbiota-derived extracellular vesicles as an interaction mechanism between the maternal microbiota and fetus, potentially playing a pivotal role in priming the prenatal immune system for gut colonization after birth. Video Abstract.

Multimodal Targeted Nanoparticle-Based Delivery System for Pancreatic Tumor Imaging in Cellular and Animal Models.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC), which ranks forth on the cancer-related death statistics still is both a diagnostic and a therapeutic challenge. Adenocarcinoma of the exocrine human pancreas originates in most instances from malignant transformation of ductal epithelial cells, alternatively by Acinar-Ductal Metaplasia (ADM). RA-96 antibody targets to a mucin M1, according to the more recent nomenclature MUC5AC, an extracellular matrix component excreted by PDAC cells. In this study, we tested the usability of multimodal nanoparticle carrying covalently coupled RA-96 Fab fragments for pancreatic tumor imaging. METHODS: In order to make and evaluate a novel, better targeting, theranostic nanoparticle, iron nanoparticles and the optical dye indocyanin green (ICG) were encapsulated into the cationic sphingomyelin (SM) consisting liposomes. RA-96 Fab fragment was conjugated to the liposomal surface of the nanoparticle to increase tumor homing ability. ICG and iron nanoparticle-encapsulated liposomes were studied in vitro with cells and (i) their visibility in magnetic resonance imaging (MRI), (ii) optical, (iii) Magnetic particle spectroscopy (MPS) and (iv) photoacoustic settings was tested in vitro and also in in vivo models. The targeting ability and MRI and photoacoustic visibility of the RA-96-nanoparticles were first tested in vitro cell models where cell binding and internalization were studied. In in vivo experiments liposomal nanoparticles were injected into the tail vain using an orthotopic pancreatic tumor xenograft model and subcutaneous pancreatic cancer cell xenografts bearing mice to determine in vivo targeting abilities of RA-96-conjugated liposomes Results: Multimodal liposomes could be detected by MRI, MPS and by photoacoustic imaging in addition to optical imaging showing a wide range of imaging utility. The fluorescent imaging of ICG in pancreatic tumor cells Panc89 and Capan-2 revealed an increased association of ICG-encapsulated liposomes carrying RA-96 Fab fragments in vitro compared to the control liposomes without covalently linked RA-96. Fluorescent molecular tomography (FMT) studies showed increased accumulation of the RA96-targeted nanoparticles in the tumor area compared to non-targeted controls in vivo. Similar accumulation in the tumor sites could be seen with liposomal ferric particles in MRI. Fluorescent tumor signal was confirmed by using an intraoperative fluorescent imaging system, which showed fluorescent labeling of pancreatic tumors. CONCLUSION: These results suggest that RA-96-targeted liposomes encapsulating ICG and iron nanoparticles can be used to image pancreatic tumors with a variety of optical and magnetic imaging techniques. Additionally, they might be a suitable drug delivery tool to improve treatment of PDAC patients.

Acid sphingomyelinase activity as an indicator of the cell stress in HPV-positive and HPV-negative head and neck squamous cell carcinoma.

Human papillomavirus (HPV) infection, especially HPV-16 and HPV-18, has been increasingly associated with head and neck squamous cell carcinoma. The treatment of HPV-positive squamous cell carcinoma has a better response to both radiotherapy and chemotherapy and presents a better prognosis for the patient. Defining the underlying mechanism of the difference might help in developing future treatment options and could be an important factor in personal therapy planning. Endogenously secreted acid sphingomyelinase (ASMase) levels in the cellular stress caused by irradiation and cisplatin were investigated. MTT assay was performed to evaluate the viability of the treated cells. Keratinocytes were used to evaluate the effects of radiation on normal tissues. Irradiation caused a dose-dependent increase in ASMase activity in both SCC9 HPV-negative, and UDSCC2 HPV-positive cells. ASMase activity in UDSCC2 cells was significantly higher than that in SCC9 cells. UDSCC cells were more sensitive to cisplatin treatment than SCC cells, and the dose-response in the activity was observed in long-time treatments when high doses of cisplatin were used. The results of the current study have clearly showed that HPV positivity should be considered as one of the determinative factors which should be considered when tumor treatments are planned. However, further studies are needed to determine the differences in cellular responses and pathways among HPV-negative and HPV-positive cells.