Citations

AbstractMicroglial activation has been recognized as a major contributor to inflammation of the epileptic brain. Seizures are commonly accompanied by remarkable microgliosis and loss of neurons. In this study, we utilize the CX3CR1GFP/+ CCR2RFP/+ genetic mouse model, in which CX3CR1+ resident microglia and CCR2+ monocytes are labeled with GFP and RFP, respectively. Using a combination of time‐lapse two‐photon imaging and whole‐cell patch clamp recording, we determined the distinct morphological, dynamic, and electrophysiological characteristics of infiltrated monocytes and resident microglia, and the evolution of their behavior at different time points following kainic acid‐induced seizures. Seizure activated microglia presented enlarged somas with less ramified processes, whereas, infiltrated monocytes were smaller, highly motile cells that lacked processes. Moreover, resident microglia, but not infiltrated monocytes, proliferate locally in the hippocampus after seizure. Microglial proliferation was dependent on the colony‐stimulating factor 1 receptor (CSF‐1R) pathway. Pharmacological inhibition of CSF‐1R reduced seizure‐induced microglial proliferation, which correlated with attenuation of neuronal death without altering acute seizure behaviors. Taken together, we demonstrated that proliferation of activated resident microglia contributes to neuronal death in the hippocampus via CSF‐1R after status epilepticus, providing potential therapeutic targets for neuroprotection in epilepsy.

ObjectiveTo assess the biologic effects of lidocaine on the viability, proliferation, and function of human adipose tissue–derived mesenchymal stromal/stem cells (MSCs) in vitro.MethodsAdipose‐derived MSCs from three donors were exposed to lidocaine at various dilutions (2 mg/mL to 8 mg/mL) and exposure times (0.5 to 4 hours). Cell number and viability, mitochondrial activity, and real‐time reverse‐transcriptase quantitative polymerase chain reaction (RT‐qPCR) were analyzed at 0 (immediate effects) or 24 and 48 hours (recovery effects) after treatment with lidocaine.ResultsTrypan blue staining showed that increasing concentrations of lidocaine decreased the number of observable viable cells. 3‐[4,5,dimethylthiazol‐2‐yl]‐5‐[3‐carboxymethoxy‐phenyl]‐2‐[4‐sulfophenyl]‐2H‐tetrazolium (MTS) assays revealed a concentration‐ and time‐ dependent decline of mitochondrial activity and proliferative ability. Gene expression analysis by RT‐qPCR revealed that adipose‐derived MSCs exposed to lidocaine express robust levels of stress response/cytoprotective genes. However, higher concentrations of lidocaine caused a significant downregulation of these genes. No significant differences were observed in expression of extracellular matrix (ECM) markers COL1A1 and DCN except for COL3A1 (P < .05). Levels of messenger RNA (mRNA) for proliferation markers (CCNB2, HIST2H4A, P < .001) and MKI67 (P < .001) increased at 24 and 48 hours. Expression levels of several transcription factors— including SP1, PRRX1, and ATF1—were modulated in the same manner. MSC surface markers CD44 and CD105 demonstrated decreased expression immediately after treatment, but at 24 and 48 hours postexposure, the MSC markers showed no significant difference among groups.ConclusionLidocaine is toxic to MSCs in a dose‐ and time‐ dependent manner. MSC exposure to high (4‐8 mg/mL) concentrations of lidocaine for prolonged periods can affect their biologic functions. Although the exposure time in vivo is short, it is essential to choose safe concentrations when applying lidocaine along with MSCs to avoid compromising the viability and potency of the stem cell therapy.

AbstractA major challenge in the development of cancer nanomedicine is the inability for nanomaterials to efficiently penetrate and deliver therapeutic agents into solid tumors. Previous studies have shown that tumor vasculature and extracellular matrix regulate the transvascular and interstitial transport of nanoparticles, both critical for successfully delivering nanomedicine into solid tumors. Within the malignant tumor microenvironment, blood vessels are morphologically abnormal and functionally exhibit substantial permeability. Furthermore, the tumor extracellular matrix (ECM), unlike that of the normal tissue parenchyma, is densely packed with collagen. These pathophysiological properties greatly impede intratumoral delivery of nanomaterials. By using an antivascular endothelial growth factor receptor antibody, DC101, and an antitransforming growth factor β1 (TGF‐β1) antibody, normalization of the tumor vasculature and ECM is achieved, respectively, in a syngeneic murine glioma model. This normalization effect results in a more organized vascular network, improves tissue perfusion, and reduces collagen density, all of which contribute to enhanced nanoparticle delivery and distribution within tumors. These findings suggest that combined vascular and ECM normalization strategies can be used to remodel the tumor microenvironment and improve nanomedicine delivery into solid tumors, which has significant implications for developing more effective combinational therapeutic strategies using cancer nanomedicine.

Pancreatic cancer, mostly pancreatic ductal adenocarcinoma (PDAC), is one of the most lethal cancer types, with an estimated 44,330 death in 2018 in the US alone. While targeted therapies and immune checkpoint inhibitors have significantly improved treatment options for patients with lung cancer and renal cell carcinomas, little progress has been made in pancreatic cancer, with a dismal 5-year survival rate currently at ~8%. Upon diagnosis, the majority of pancreatic cancer cases (~80%) are already metastatic. Thus, identifying ways to reduce pancreatic cancer metastasis is an unmet medical need. Furthermore, pancreatic cancer is notorious resistant to chemotherapy. While Kirsten RAt Sarcoma virus oncogene (K-RAS) mutation is the major driver for pancreatic cancer, specific inhibition of RAS signaling has been very challenging, and combination therapy is thought to be promising. In this study, we report that combination of hedgehog (Hh) and Mitogen-activated Protein/Extracellular Signal-regulated Kinase Kinase (MEK) signaling inhibitors reduces pancreatic cancer metastasis in mouse models. In mouse models of pancreatic cancer metastasis using human pancreatic cancer cells, we found that Hh target gene Gli1 is up-regulated during pancreatic cancer metastasis. Specific inhibition of smoothened signaling significantly altered the gene expression profile of the tumor microenvironment but had no significant effects on cancer metastasis. By combining Hh signaling inhibitor BMS833923 with RAS downstream MEK signaling inhibitor AZD6244, we observed reduced number of metastatic nodules in several mouse models for pancreatic cancer metastasis. These two inhibitors also decreased cell proliferation significantly and reduced CD45+ cells (particularly Ly6G+CD11b+ cells). We demonstrated that depleting Ly6G+ CD11b+ cells is sufficient to reduce cancer cell proliferation and the number of metastatic nodules. In vitro, Ly6G+ CD11b+ cells can stimulate cancer cell proliferation, and this effect is sensitive to MEK and Hh inhibition. Our studies may help design novel therapeutic strategies to mitigate pancreatic cancer metastasis.

AbstractIntroductionThe outcomes of repeated cardiovascular implantable electronic device (CIED) lead extraction have not been well studied. We sought to determine the indications, outcomes, and safety of repeated lead extraction procedures.MethodsThis retrospective study was conducted using data from two medical centers, including 38 patients who had undergone two or more lead extraction procedures compared to 439 patients who had a single procedure. The electronic medical records and procedural databases were reviewed to determine the indications, procedural characteristics, and outcomes. The outcomes of the first procedure were compared to the outcomes of subsequent procedures.ResultsThe 5‐year cumulative probability of a repeated extraction procedure was 11% (95% confidence interval, 7%–15%). In 439 patients who underwent single lead extractions, 72% had device and lead related infections as the procedure indication compared to 39% for 38 patients who underwent repeated extraction (P < 0.001). The mean duration from device reimplant to repeated extraction procedures was 63 ± 48 months. Ninety‐eight percent of the leads were removed completely in repeated procedures, similar to the 95% success rate of the first procedure (P = 0.51). There was no significant difference in major complication rate in the first or repeated extractions (2.6% vs 5.2%, P = 0.79).ConclusionsRepeated transvenous lead extraction is not uncommon. It had a high success rate comparable to that of the initial procedure and was not associated with an increased incidence of adverse events.

BackgroundTransplantation of mesenchymal stem cells (MSCs) is a promising therapy for degenerative spine conditions. However, cell therapy for painful spine degeneration presently requires use of contrast agents during fluoroscopy‐guided injections, and the effects of these agents on MSCs represents a gap in knowledge.ObjectiveTo investigate the biological effects of contrast media (CM) that are coinjected with MSCs.DesignProspective observational study.SettingAcademic medical center.ParticipantsPatient‐derived clinical‐grade culture expanded MSCs.InterventionsIohexol (Omnipaque300) was reduced to 12.5%, 25%, 50%, and 100% of the stock solution and incubated with MSCs for 30 minutes, 4 hours, and 48 hours. We also used complete media and 12.5%, 25%, 50%, 100% of phosphate‐buffered saline as a control group.Main Outcome MeasuresWe examined cytotoxicity of iohexol at different concentrations and exposure duration, as well as the potential for recovery over time. Cell counts, mitochondrial activity, and quantitative real time reverse‐transcriptase polymerase chain reaction of related genes were analyzed immediately after exposure (day 0) and after 2 days of exposure (day 2).ResultsHuman MSCs exhibit a time‐ and concentration‐dependent cytotoxic response to iodinated CM. A brief, 30‐minute exposure did not affect MSCs function and viability. However, extended treatment with iohexol for 4 hours at 50% or higher concentration had a significant impact on both viability and gene expression in MSCs.ConclusionsIohexol is cytotoxic to MSCs in a time‐and concentration‐dependent manner. Hence, the concentration of CM that accompanies MSC injections should be carefully considered during MSC therapy for disk‐degenerative diseases.Level of EvidenceIII.