Indocyanine green-loaded platelet activated by photodynamic and photothermal effects for selective control of wound repair.

OBJECTIVE: Prompt and effective wound repair is an essential strategy to promote recovery and prevent infection in patients with various types of trauma. Platelets can release a variety of growth factors upon activation to facilitate revascularization and tissue repair, provided that their activation is uncontrollable. The present study is designed to explore the selective activation of platelets by photodynamic and photothermal effects (PDE/PTE) as well as the trauma repair mediated by PDE/PTE. MATERIALS AND METHODS: In the current research, platelets were extracted from the blood of mice. Indocyanine green (ICG) was applied to induce PDE/PTE. The uptake of ICG by platelets was detected by laser confocal microscopy and flow cytometry. The cellular integrity was measured by microscopy. The reactive oxygen species (ROS) generation and temperature of platelets were assayed by 2,7-Dichlorodihydrofluorescein diacetate (DCFH-DA) and temperature detector. The activation of platelets was measured by western blots (WB), dynamic light scattering (DLS), and scanning electron microscopy (SEM). The release of growth factor was detected by enzyme-linked immuno sorbent assay (Elisa), wherein the in vitro cell proliferation was investigated by 5-Ethynyl-2'-deoxyuridine (EDU) assay. The wound infection rates model and histological examination were constructed to assay the ICG-loaded platelet-mediated wound repair. RESULTS: Platelets could load with ICG, a kind of photodynamic and photothermal agent, as carriers and remain intact. Near-infrared (NIR) laser irradiation of ICG-loaded platelets (ICG@PLT) facilitated higher temperature and ROS generation, which immediately activated ICG@PLT, as characterized by increased membrane p-selectin (CD62p), cyclooxygenase-2 (COX-2), thromboxane A2 receptor (TXA2R) expression, elevated hydrated particle size, and prominent aggregation in platelets. Further investigation revealed that massive insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) were released from the activated ICG@PLT, which also promoted the proliferation of endothelial cells and keratinocytes in co-culture. In consequence, activated platelets and increased neovascularization could be observed in rats with wound infection treated by ICG@PLT in the presence of NIR. More impressively, the hydrogel containing ICG@PLT accelerated wound healing and suppressed inflammation under NIR, exhibiting excellent wound repair properties. CONCLUSION: Taken together, the current work identified that platelets could be activated by PDE/PTE and thereby release growth factor, potentiating wound repair in a controlled manner.

A Study of the Efficacy and Safety of Aerobic Exercise Training in Pulmonary Arterial Hypertension (the Saturday Study): Protocol for a Prospective, Randomized, and Controlled Trial.

Background: Patients with pulmonary arterial hypertension (PAH) have reduced exercise capacity and poor quality of life. Exercise-based rehabilitation in PAH results in clinically relevant improvements in exercise capacity and hemodynamics. To clarify the mechanism, we will evaluate the effect of aerobic exercise training rehabilitation on right ventricular (RV) remodeling and function as determined measured by cardiac magnetic resonance imaging (CMR). Methods: We will conduct a 26-week multicenter randomized controlled trial. Patients on stable and unchanged PAH-targeted medication are randomly assigned (1:1) to the control and training groups. The primary endpoint is the RV stroke volume (RVSV) change from baseline to Week 26, determined by CMR. Comprehensive RV function is also performed using CMR. Other characteristics of the RV and left ventricle, World Health Organization functional class, 6-min walk distance, and N-terminal pro-B-type natriuretic peptide are included in secondary endpoints. We also investigate the proteomic, metabolomic, and transcriptomic changes after exercise training as exploratory endpoints. Ethics and Dissemination: The study and protocol were approved by the Ethics Committee of Shanghai Pulmonary Hospital (Approved No. of ethics committee: L20-17). The results will be disseminated at medical conferences and in journal publications. All participants will sign written informed consent. Trial Registration Number: ChiCTR2000031650.