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Objective: Fluorescence contrast technology using indocyanine green (ICG) could be useful for the rapid, dynamic, and objective assessment of blood vessels and the surrounding tissues when combined with near-infrared (NIR) imaging. Although ICG is a clinically available NIR fluorescence imaging probe, it can easily aggregate and is, thus, unstable. In the present study, we examined the efficacy of a host–guest ICG–β-cyclodextrin (CD) complex, which is used in pharmaceutics to improve the water solubility, stability, and bioavailability of hydrophobic molecules, for NIR imaging after hind footpad administration in a rat model. Methods: To verify the performance of the ICG-β-CD complex with the host–guest self-assembly method in vivo, we performed simultaneous small animal (IVIS Spectrum system; PerkinElmer, Waltham, MA) and clinical (DIGI-MIH-001 near-infrared fluorescence imaging system; Beijing Digital Precision Medical Technology Co, Ltd, Beijing, China) imaging and evaluated the fluorescent properties of the ICG-β-CD complex in the hind footpad model of Sprague-Dawley male rats. Results: We successfully prepared the ICG-β-CD complex. Compared with ICG, in vivo experiments showed that this complex had reduced absorbance at 710 nm and increased absorbance at 780 nm, indicating that it could prevent the dimeric aggregation of ICG, and a significantly higher fluorescence intensity at 730 nm excitation. After injection of 1.25 mg/mL of ICG or ICG-β-CD complex solutions into the rat hind footpad, fluorescent NIR lymphatic images were observed with both imaging systems. During the 12-hour observation period, the signal background ratio of ICG-β-CD showed a greater acute increase and a higher signal background ratio compared with ICG. The signal background ratio of ICG-β-CD was 125 to 100 from 260 to 540 minutes. These in vivo data suggest that ICG-β-CD has greater diffusion from the injection site and faster transport to the lymphatic system compared with ICG. Conclusions: ICG-β-CD showed faster lymphatic transport than ICG, allowing for more rapid lymphatic NIR imaging. Thus, the ICG-β-CD complex might be a promising fluorescent agent for clinical lymphatic NIR imaging. : Clinical Relevance: The lymphatic system plays a crucial role in maintaining tissue fluid homeostasis by draining protein-rich fluid from the perivascular interstitial spaces back into the circulation. The lymphatic system also plays a variety of roles in the progression of some peripheral vascular diseases, including venous leg ulcers, atherosclerotic vascular disease, and severe foot infection. Understanding the dynamic changes of the lymphatic fluid is indispensable for a variety of clinical situations and research areas. We investigated the potential feasibility of the indocyanine green–β-cyclodextrin complex in clinical applications using clinically available near-infrared fluorescence imaging equipment.

Introduction: Intermittent hypoxia (IH), an important feature of obstructive sleep apnea, enhances the function of lung cancer cell-derived extracellular vesicles (EVs) to exacerbate the immunosuppressive properties of macrophages. Herein, we investigated the effects of EVs obtained from lung adenocarcinoma cells cultured under IH on macrophage polarization. Methods: The M1-type and M2-type tumor-associated macrophages (TAMs) in tissues from lung adenocarcinoma cases with (n = 10) or without (n = 12) OSA were assessed by immunohistochemical studies. EVs obtained from A549 cells grown under normoxia (EV-NA) or IH (EV-IH) were isolated and cocultured with macrophages. MicroRNA sequencing was used to determine discrepant miRNAs in EVs, selecting miR-20a-5p for subsequent experiments. Next, reverse transcription-quantitative polymerase chain reaction, flow cytometry, luciferase reporter assay, western blotting assay, and gain- and loss-of-function assays were used to explore the mechanism by which miR-20a-5p promotes M2 macrophage polarization by targeting phosphatase and Tensin homolog gene (PTEN). Results: Stromal M2 TAMs were highly abundant in patients with lung adenocarcinoma and obstructive sleep apnea. Macrophages treated with EV-IH that highly expressed miR-20a-5p showed the M2 phenotype. Luciferase reporter assay confirmed PTEN as a target of miR-20a-5p. Transfection of miR-20a-5p mimics decreased PTEN expression, upregulated M2 polarization markers, and promoted Akt phosphorylation in macrophages, while transfection with a miR-20a-5p inhibitor had the opposite effects. Furthermore, miR-20a-5p inhibition in macrophages eliminated the PTEN downregulation, Akt phosphorylation, and upregulation of M2 polarization markers induced by EV-IH transfection. Conclusion: These findings indicate that EVs obtained from lung adenocarcinoma cells cultured under IH deliver miR-20a-5p to promote M2 macrophage polarization by targeting PTEN.

Summary: Heart failure (HF) is a complex syndrome affecting millions of people around the world. Over the past decade, the therapeutic potential of targeting epigenetic regulators in HF has been discussed extensively. Recent advances in next-generation sequencing techniques have contributed substantial progress in our understanding of the role of DNA methylation, post-translational modifications of histones, adenosine triphosphate (ATP)-dependent chromatin conformation and remodeling, and non-coding RNAs in HF pathophysiology. In this review, we summarize epigenomic studies on human and animal models in HF. Key Words: cardiac hypertrophy, epigenetics, heart failure