Effect of down-regulation of let-7c/g on triggering a double-negative feedback loop and promoting restenosis

Background:Excessive proliferation and migration of vascular smooth muscle cells(VSMCs)are the main causes of restenosis(RS)in diabetic lower extremity arterial disease(LEAD).However,the relevant pathogenic mechanisms are poorly understood.Methods:In this study,we introduced a“two-step injury protocol”rat RS model,which started with the induction of atherosclerosis(AS)and was followed by percutaneous transluminal angioplasty(PTA).Hematoxylin-eosin(HE)staining and immunohistochemistry staining were used to verify the form of RS.Two-step transfection was performed,with the first transfection of Lin28a followed by a second transfection of let-7c and let-7g,to explore the possible mechanism by which Lin28a exerted effects.5-ethynyl-2΄-deoxyuridine(EdU)and Transwell assay were performed to evaluate the ability of proliferation and migration of VSMCs.Western blotting and quantitative real-time polymerase chain reaction(qRT-PCR)were performed to detect the expression of Lin28a protein and let-7 family members.Results:Using a combination of in vitro and in vivo experiments,we discovered that let-7c,let-7g,and microRNA98(miR98)were downstream targets of Lin28a.More importantly,decreased expression of let-7c/let-7g increased Lin28a,leading to further inhibition of let-7c/let-7g.We also found an increased level of let-7d in the RS pathological condition,suggesting that it may function as a protective regulator of the Lin28a/let-7 loop by inhibiting the proliferation and migration of VSMCs.Conclusion:These findings indicated the presence of a double-negative feedback loop consisting of Lin28a and let-7c/let-7g,which may be responsible for the vicious behavior of VSMCs in RS.

Novel biomonitoring method for determining five classes of legacy and alternative flame retardants in human serum samples

Flame retardants(FRs)are ubiquitous in environment and biota and may pose harm to human health.In recent years,concern regarding legacy and alternative FRs has been intensified due to their widespread production and increasing contamination in environmental and human matrices.In this study,we developed and validated a novel analytical method for simultaneous determination of legacy and alternative FRs,including polychlorinated naphthalenes(PCNs),short-and middle-chain chlorinated paraffins(SCCPs and MCCPs),novel brominated flame retardants(NBFRs),and organophosphate esters(OPEs)in human serum.Serum samples were prepared by liquid-liquid extraction using ethyl acetate,and purified with Oasis®HLB cartridge and Florisil–silica gel columns.Instrumental analyses were carried out using gas chromatography-triple quadrupole mass spectrometry,highresolution gas chromatography coupled with high-resolution mass spectrometry,and gas chromatography coupled with quadrupole time-of-flight mass spectrometry,respectively.The proposed method was validated for linearity,sensitivity,precision,accuracy,and matrix effects.Method detection limits for NBFRs,OPEs,PCNs,SCCPs,and MCCPs were 4.6×10^(–4)–8.6×10^(–2),4.3×10^(–3)–1.3,1.1×10^(–5)–1.0×10^(–4),1.5,and 9.0×10–1 ng/mL,respectively.Matrix spike recoveries ranged from 73%–122%,71%–124%,75%–129%,92%–126%,and 94%–126%for NBFRs,OPEs,PCNs,SCCPs,and MCCPs,respectively.The analytical method was applied for detection of real human serum.CPs were the dominant FRs in serum,indicating CPs were widely presented in human serum and should be pay more attention for their health risk.

Survey on Arteriovenous Fistula in Maintenance Hemodialysis Patients with Type 2 Diabetic Nephropathy

This paper summed up the characteristics of native arteriovenous fistulas(AVFs) in maintenance hemodialysis patients with type 2 diabetic nephropathy(DN) in Chinese hemodialysis centers.A survey was conducted on AVF in maintenance hemodialysis patients with type 2 DN.A total of 224 cases of maintenance hemodialysis patients were included in this study,among which,65 cases in DN group,33 cases in diabetes mellitus(DM) group and 126 cases in non-diabetic control(C) group.Hemoglobin,albumin,blood urea nitrogen, parathyroid hormone and calcium-phosphate product of the three groups of patients were not significantly different. Glycated hemoglobin A1c of DN group and DM group was not significant different.AVF life of(28.7±10.0) months in DN group was significantly shorter than that of(36.5±19.4) months in C group(statistic probability P<0.01),and AVF life of(32.5±10.1) months in DM group(P<0.05) was also shorter than that in C group, while there was no significant difference in AVF life between DN group and DM group.Proportion of upper arm fistula in DN patients(11/65) was significantly higher than that in C group(6/123,P<0.01).Life of AVF in patients with DN was relatively short,with more times of angioplasty and greater possibility of selecting upper arm internal fistula.