Research progress of exosomes in the diagnosis and treatment of sepsis / 中华危重病急救医学

Sepsis is a life-threatening organ dysfunction caused by infection that lead to dysregulation of the host response. Sepsis and septic shock with a high mortality threaten human health at present, which are important medical and health problems. Early diagnosis and treatment decision-making for sepsis and septic shock still need to be improved. Exosomes are extracellular vesicles with a diameter of 30-150 nm formed by the fusion of multi-vesicle bodies and cell membranes. Exosomes can effectively transport a variety of bioactive substances such as proteins, lipids, RNA, DNA, and participate in the regulation of inflammatory response, immune response, infection and other pathophysiological processes. In recent years, exosomes have become one of the important methods for the diagnosis and treatment of systemic inflammatory diseases. This article will focus on the basic and clinical research of sepsis, and focus on the research progress of exosomes in the diagnosis and targeted therapy of sepsis.

Establishment of a droplet digital PCR method for the detection of hepatitis B virus covalently closed circular DNA / 临床肝胆病杂志

ObjectiveTo establish a droplet digital PCR (ddPCR) method for detecting hepatitis B virus (HBV) covalently closed circular DNA (cccDNA). MethodsHBV cccDNA standard substance was constructed, and HBV cccDNA primers and probes were designed based on the structural differences between HBV cccDNA and relaxed circular DNA (rcDNA). HBV plasmid was amplified to obtain HBV cccDNA standard substance, and a ddPCR detection method was established with the standard substance after gradient dilution as the template for HBV cccDNA detection; the limit of detection and repeatability of this method were analyzed. Liver tissue samples were collected from 20 patients who attended Beijing YouAn Hospital, Capital Medical University, from June 2017 to October 2020, all of whom were diagnosed with HBV infection, and DNA of the samples was extracted and digested with plasmid-safe ATP-dependent DNA enzyme to obtain HBV cccDNA template; the ddPCR detection method was evaluated in clinical samples and was compared with the quantitative real-time PCR (qPCR) detection method. The chi-square test was used for comparison of categorical data between the two groups. ResultsThe HBV cccDNA detection method based on ddPCR was established, which accurately detected HBV cccDNA in standard substance after gradient dilution, with a limit of detection of 1 copy/μl, and the coefficients of variation of 1×103, 1×102, and 1×101 copies/μl standard substances were 441%, 3.98%, and 5.09%, respectively. HBV cccDNA was detected in the samples of 20 patients with HBV infection; the ddPCR detection method detected HBV cccDNA in 17 patients, with a positive rate of 85%, while the qPCR detection method detected HBV cccDNA in 11 patients, with a positive rate of 55%, and there was a significant difference between the two methods (χ2=4.286, P=0038). ConclusionThe established ddPCR method for detecting HBV cccDNA has a low limit of detection and good repeatability, which provides an effective tool for further clinical detection.