1.Eph-B4Activates TGF-β Signaling:a Novel Pathway Through Which Eph-B4May Limit Vein Graft Thickening2.An Postoperative Retrospective Analysis Of A Serjes Of Patients With Chronic Venous Insufficiency

Background and objectiveVeins are the most commonly used conduit for coronary and peripheral artery bypass; placement of a vein into the higher pressure and flow of the arterial circulation results in adaptation of the vein to the arterial environment, a process termed vein graft "arterialization" or "adaptation." Successful vein graft adaptation is a complex process that includes cell proliferation and migration, programmed cell death, and changes in production and degradation of the extracellular matrix as well as coordinating growth factors, producing a thicker walled vessel.The natural history of normal human vein graft adaptation is incompletely described, as excision of patent vein grafts that have adapted well to the arterial circulation is not ordinarily performed for ethical reasons; furthermore, reported specimens are often taken from abnormal or failing vein grafts. In addition, although in vito and in vivo models of vein graft adaptation to the arterial circulation are well described, the regulation of this complex process by factors unique to aged hosts, which are relevant to elderly patients undergoing bypass surgery, is not well understood. Similarly, many of the in vitro models, noted above, have only examined arterial endothelial responses to shear stress, not venous endothelial responses.Advances in developmental biology have demonstrated that there are genetic predeterminants of arterial and venous endothelium, and the molecular distinction between arteries and veins is becoming established. How genes are regulated during vein graft adaptation is beginning to be explored; however, there are little data regarding regulation of genes associated with arterial or venous identity, in postnatal adults and aged animals. For example,the Ephrin ligands and Eph receptors are an important class of signaling molecules that are differentially expressed on arteries and veins.Ephrin-B2is a marker of arterial endothelium and smooth muscle and persists into adult vessels. Conversely, Eph-B4, a receptor tyrosine kinase, is a marker of venous cells. Previous studies have shown that Eph-B4inhibits vein graft thickening after arterial placement; however, the molecular mechanisms by which Eph-B4regulates venous remodeling and limits graft intimal thickening remain largely unknown.Transforming growth factor beta (TGF-β) signaling pathway plays an important role involved in many cellular processes including cell growth, cell differentiation, apoptosis, cellular homeostasis and other cellular functions. Similarly, the TGF-(3pathways are also important signaling pathways involved in neointimal hyperplasia and fibrosis in vein grafts. The aim of our experiments is to investigate a possible link between the EphB4and TGF-β pathwaysMethods1. Animal model experiment:Vein graft model is established.2. Cell culture experiment:Mouse lung endothelial cells (MLEC) were used as a model of vein graft endothelium as they are Eph-B4positive3. Activate experiment:Eph-B4was activated in MLEC using its bivalent ligand Ephrin-B2/Fc in a time course manner.4. Western blot experiment:TGF-beta pathway activation was assessed by Smad2(Smad2is a soluble protein kinase in the TGF-B pathway) phosphorylation on Western blot analysis.5. Inhibitor experiment:MLEC were pretreated with wortmannin, a PI3K inhibitor, and PD-98059, a MEK1inhibitor and so on.6. immunofluorescence experiment:Analyze vein graft tissue for TGF-β receptor and smad2phosphorylation 7. Data was analyzed with one-way ANOVA.Results:1. Time course ligand stimulation with TGF-beta is associated with a single peak increase of Smad2phosphorylation.2. Time course ligand stimulation of Eph-B4with Ephrin-B2/Fc is associated with bimodal phosphorylation of Smad2, with peak phosphorylation of Smad2at5and60minutes.3.10nM wortmannin pretreatment followed by a time course stimulation with Ephrin-B2/Fc eliminates the late peak of Smad2phosphorylation. The early peak of Smad2phosphorylation is unaffected.4. U0126(25uM) pretreatment followed by a time course stimulation with Ephrin-B2/Fc eliminates the early peak of Smad2phosphorylation. The late peak of Smad2phosphorylation is unaffected.5. Pretreatment of MLEC with increasing doses of PD-98059followed by5minute Ephrin-B2/Fc stimulation does not change Smad2phosphorylation above Ephrin-B2/Fc stimulation alone.6. MLECs are stimulated with Ephrin-B2/Fc and TGF-β1separately and no bimodal phosphorylation of Akt and p44/42MAPK (Erkl/2) is observed.7. Under immunofluorescence microscope, we can see that phosphorylation of Smad2and expression level of EphB4and TGF-β are increased on vein graft tissue(day7) in comparison with normal vein.Conclusions1. Unlike TGF-beta, Eph-B4activation stimulates phosphorylation of Smad2, an initial step in the TGF-beta signaling pathway in a novel bimodal distribution.2. The late peak of Smad2phosphorylation is inhibited by Wortmannin, a PI3K inhibitor, suggesting multiple points of control.3. These results suggest a possible novel molecular mechanism by which Eph-B4regulates vein graft thickening. Background and purpose:Lower extremity chronic venous insufficiency are a common clinical problem, affecting up to25%of women and15%of men in the world, particularly with the higher incidence (50%) in people over50years of age. Varicose veins are main clinical symptom.The incidence of varicose veins reaches8.89%in China. For nearly a decade, the incidence of this condition has been rising steadily such that lower extremity chronic venous insufficiency has become one of the most common vascular diseases.Early symptoms of varicose veins include lower extremity superficial veins that are circuitous and dilated. Patients often complain of pain when standing that disappears when they lie down or when they walk. As the illness progresses, lower extremity skin dystrophy can appear due to an impairment of blood circulation, including skin atrophy, desquamation, pruritus, pigmentation, skin and subcutaneous tissue scleroma. Eczema and ulcers can form, especially in the lower segment of dorsumpedis, ankle and crus.The most effective treatment method of lower extremity varicose veins remains surgical correction. Greater saphenous vein (GSV) high ligation, stripping and the perforating veins ligation for the treatment of varicose veins became the surgical procedure of choice for the treatment of lower extremity varicose veins. However, the postoperative recurrence rate is relatively high, ranging from7to65%after long-term follow-up. Sarin et al reported that the recurrent rate of GSV reflux after ligation and stripping was18%while the rate of recurrence after high ligation alone was45%, which occurred as early as3months after treatment. Similarly, Dwerryhouse et al found a recurrence rate of29%after GSV ligation and stripping and71%after high ligation alone. However, the reason for recurrence of varicose veins is poorly documented and understood.The purpose of this paper is to evaluate the reasons of postoperative recurrence of varicose veins of the lower extremity. We presented a retrospective study of92cases with109limbs who had previously undergone treatment for varicose veins who presented with recurrence at a single center, analyzing the clinical manifestations and imaging findings to better understand the factors underlying varicose vein recurrence.Methods:A total of92consecutive cases of recurrent varicose veins after previous surgical intervention presenting to Shandong Provincial Hospital between August2005to August2011were reviewed. The collected data included clinical characteristics, symptoms and imaging results, such as color Doppler and venography of lower limbs.Results:92patients with109limbs were graded according to Clinical Etiology Anatomic and Pathophysiologic (CEAP) classification:37cases (34%) were grade4,40cases (37%) were grade5and32(29%) cases were grade6.101limbs (92.7%) showed reflux of the perforating veins,86(79%) of limbs showed reflux of the superficial femoral vein, of which mild reflux was present in25(22.8%), moderate reflux in40(37%), severe reflux in21(19%). There were4limbs without valves(3.67%).82limbs (75%) showed residual saphenous vein,19limbs showed post-thrombotic syndrome (PTS)(17.4%),1limb showed the Klippel-Trenaunay syndrome (KTS)(0.9%),2limbs showed Cockett syndrome(2.8%).Conclusion:Our study identified that failure to ligate perforating veins, failure to perform surgical interventions and underlying etiology of the patient's varicose, were the main reasons for varicose vein recurrence. Reducing the incidence of recurrent varicose veins after surgical correction will likely require the more careful use of preoperative imaging to tailor surgical intervention for individual patients.