Extracellular histones stimulate collagen expression in vitro and promote liver fibrogenesis in a mouse model via the TLR4-MyD88 signaling pathway

BACKGROUND Liver fibrosis progressing to liver cirrhosis and hepatic carcinoma is very common and causes more than one million deaths annually.Fibrosis develops from recurrent liver injury but the molecular mechanisms are not fully understood.Recently,the TLR4-MyD88 signaling pathway has been reported to contribute to fibrosis.Extracellular histones are ligands of TLR4 but their roles in liver fibrosis have not been investigated.AIM To investigate the roles and potential mechanisms of extracellular histones in liver fibrosis.METHODS In vitro,LX2 human hepatic stellate cells(HSCs)were treated with histones in the presence or absence of non-anticoagulant heparin(NAHP)for neutralizing histones or TLR4-blocking antibody.The resultant cellular expression of collagen I was detected using western blotting and immunofluorescent staining.In vivo,the CCl4-induced liver fibrosis model was generated in male 6-week-old ICR mice and in TLR4 or MyD88 knockout and parental mice.Circulating histones were detected and the effect of NAHP was evaluated.RESULTS Extracellular histones strongly stimulated LX2 cells to produce collagen I.Histone-enhanced collagen expression was significantly reduced by NAHP and TLR4-blocking antibody.In CCl4-treated wild type mice,circulating histones were dramatically increased and maintained high levels during the duration of fibrosisinduction.Injection of NAHP not only reduced alanine aminotransferase and liver injury scores,but also significantly reduced fibrogenesis.Since the TLR4-blocking antibody reduced histone-enhanced collagen I production in HSC,the CCl4 model with TLR4 and MyD88 knockout mice was used to demonstrate the roles of the TLR4-MyD88 signaling pathway in CCl4-induced liver fibrosis.The levels of liver fibrosis were indeed significantly reduced in knockout mice compared to wild type parental mice.CONCLUSION Extracellular histones potentially enhance fibrogenesis via the TLR4–MyD88 signaling pathway and NAHP has therapeutic potential by detoxifying extracellular histones.

Comparative Analysis of the Effect of Local Citrate Anticoagulation and Non-anticoagulation in Extended Intermittent Renal Replacement Therapy(PIRRT)

Objective:To observe the anticoagulant effect of local citrate anticoagulation and non-anticoagulation in prolonged intermittent renal replacement therapy(PITTR).Methods:From October 2018 to October 2019,30 patients with a high risk of bleeding who received PIRRT treatment in our hospital were selected and divided into RCA group(citrate group)and control group(non-anticoagulant group),15 cases in each group.The anticoagulant efficiency,filter service life,coagulation function,and blood gas indexes were compared between the two groups.Results:(1)the anticoagulant effective rate of the RCA group was higher than that of the control group,and the use time of the filter was longer than that of the control group(P<0.05).(2)There was no significant difference in Pt and APTT between the two groups before and after treatment(P>0.05).(3)There was no significant difference in plasma calcium concentration between the two groups before treatment,4,6 and 8 h after treatment(P>0.05).(4)In the RCA group,the pH value and be valued at 4,6 and 8 h after treatment were higher than those before treatment,but they were in the normal range,and the difference was statistically significant(P<0.05).Conclusion:In the extended intermittent renal replacement therapy,the effect of local citrate anticoagulation is better than that of non-anticoagulant therapy,which can prolong the service life of the filter,and there are no adverse reactions such as prolonged coagulation time,hypocalcemia,and metabolic acid-base imbalance.