A mouse model with high clonal barcode diversity for joint lineage, transcriptomic, and epigenomic profiling in single cells.

Cellular lineage histories and their molecular states encode fundamental principles of tissue development and homeostasis. Current lineage-recording mouse models have insufficient barcode diversity and single-cell lineage coverage for profiling tissues composed of millions of cells. Here, we developed DARLIN, an inducible Cas9 barcoding mouse line that utilizes terminal deoxynucleotidyl transferase (TdT) and 30 CRISPR target sites. DARLIN is inducible, generates massive lineage barcodes across tissues, and enables the detection of edited barcodes in ∼70% of profiled single cells. Using DARLIN, we examined fate bias within developing hematopoietic stem cells (HSCs) and revealed unique features of HSC migration. Additionally, we established a protocol for joint transcriptomic and epigenomic single-cell measurements with DARLIN and found that cellular clonal memory is associated with genome-wide DNA methylation rather than gene expression or chromatin accessibility. DARLIN will enable the high-resolution study of lineage relationships and their molecular signatures in diverse tissues and physiological contexts.

Single-cell lineage tracing unveils a role for TCF15 in haematopoiesis.

Bone marrow transplantation therapy relies on the life-long regenerative capacity of haematopoietic stem cells (HSCs)1,2. HSCs present a complex variety of regenerative behaviours at the clonal level, but the mechanisms underlying this diversity are still undetermined3-11. Recent advances in single-cell RNA sequencing have revealed transcriptional differences among HSCs, providing a possible explanation for their functional heterogeneity12-17. However, the destructive nature of sequencing assays prevents simultaneous observation of stem cell state and function. To solve this challenge, we implemented expressible lentiviral barcoding, which enabled simultaneous analysis of lineages and transcriptomes from single adult HSCs and their clonal trajectories during long-term bone marrow reconstitution. Analysis of differential gene expression between clones with distinct behaviour revealed an intrinsic molecular signature that characterizes functional long-term repopulating HSCs. Probing this signature through in vivo CRISPR screening, we found the transcription factor TCF15 to be required and sufficient to drive HSC quiescence and long-term self-renewal. In situ, Tcf15 expression labels the most primitive subset of true multipotent HSCs. In conclusion, our work elucidates clone-intrinsic molecular programmes associated with functional stem cell heterogeneity and identifies a mechanism for the maintenance of the self-renewing HSC state.

The miR156/SPL12 module orchestrates fruit colour change through directly regulating ethylene production pathway in blueberry.

Colour change is an important event during fruit ripening in blueberry. It is well known that miR156/SPLs act as regulatory modules mediating anthocyanin biosynthesis and ethylene plays critical roles during colour change, but the intrinsic connections between the two pathways remain poorly understood. Previously, we demonstrated that blueberry VcMIR156a/VcSPL12 affects the accumulation of anthocyanins and chlorophylls in tomato and Arabidopsis. In this study, we first showed that VcMIR156a overexpression in blueberry led to enhanced anthocyanin biosynthesis, decreased chlorophyll accumulation, and, intriguingly, concomitant elevation in the expression of ethylene biosynthesis genes and the level of the ethylene precursor ACC. Conversely, VcSPL12 enhanced chlorophyll accumulation and suppressed anthocyanin biosynthesis and ACC synthesis in fruits. Moreover, the treatment with ethylene substitutes and inhibitors attenuated the effects of VcMIR156a and VcSPL12 on pigment accumulation. Protein-DNA interaction assays indicated that VcSPL12 could specifically bind to the promoters and inhibit the activities of the ethylene biosynthetic genes VcACS1 and VcACO6. Collectively, our results show that VcMIR156a/VcSPL12 alters ethylene production through targeting VcACS1 and VcACO6, therefore governing fruit colour change. Additionally, VcSPL12 may directly interact with the promoter region of the chlorophyll biosynthetic gene VcDVR, thereby activating its expression. These findings established an intrinsic connection between the miR156/SPL regulatory module and ethylene pathway.

Identification of R2R3-MYB family in blueberry and its potential involvement of anthocyanin biosynthesis in fruits.

BACKGROUND: Blueberries (Vaccinium corymbosum) are regarded as "superfoods" attributed to large amounts of anthocyanins, a group of flavonoid metabolites, which provide pigmentation in plant and beneficial effects for human health. MYB transcription factor is one of vital components in the regulation of plant secondary metabolism, which occupies a dominant position in the regulatory network of anthocyanin biosynthesis. However, the role of MYB family in blueberry responding to anthocyanin biosynthesis remains elusive. RESULTS: In this study, we conducted a comprehensive analysis of VcMYBs in blueberry based on the genome data, including phylogenetic relationship, conserved motifs, identification of differentially expressed MYB genes during fruit development and their expression profiling, etc. A total of 437 unique MYB sequences with two SANT domains were identified in blueberry, which were divided into 3 phylogenetic trees. Noticeably, there are many trigenic and tetragenic VcMYBs pairs with more than 95% identity to each other. Meanwhile, the transcript accumulations of VcMYBs were surveyed underlying blueberry fruit development, and they showed diverse expression patterns, suggesting various functional roles in fruit ripening. More importantly, distinct transcript profiles between skin and pulp of ripe fruit were observed for several VcMYBs, such as VcMYB437, implying the potential roles in anthocyanin biosynthesis. CONCLUSIONS: Totally, 437 VcMYBs were identified and characterized. Subsequently, their transcriptional patterns were explored during fruit development and fruit tissues (skin and pulp) closely related to anthocyanin biosynthesis. These genome-wide data and findings will contribute to demonstrating the functional roles of VcMYBs and their regulatory mechanisms for anthocyanins production and accumulation in blueberry in the future study.

Let-7c-5p down-regulates immune-related CDCA8 to inhibit hepatocellular carcinoma.

OBJECTIVE: The aim of this study is to investigate the effect of let-7c-5p on the malignant behaviors of hepatocellular carcinoma (HCC) and its specific molecular pathway. METHODS: Differential expression and survival analysis of let-7c-5p were obtained from The Cancer Genome Atlas database, and then its expression level was preliminarily verified through qPCR. The effect of let-7c-5p on the malignant phenotype of HCC cells was subsequently evaluated using CCK-8, transwell, wound healing, and flow cytometry assays. Downstream mRNA regulated by let-7c-5p was identified and confirmed by ENCORI database, dual-luciferase reporter, and western blot assays. The immunocorrelation of genes was evaluated by Xiantao tool, and TIMER and TISIDB databases. RESULTS: The expression level of let-7c-5p in HCC was obviously reduced, which was found to be closely associated with the short survival time of HCC patients. Cell phenotypic experiments showed that let-7c-5p inhibited proliferation, invasion, and migration and promoted apoptosis of HCC cells. Dual-luciferase reporter and western blot analysis demonstrated that CDCA8 is a downstream mRNA of let-7c-5p and is negatively regulated by it. Rescue experiment revealed that CDCA8 reversed the effect of let-7c-5p on the malignant phenotype of HCC cells. Furthermore, analysis of the public database revealed that CDCA8 is related to some immune cells and immunomodulators, and that it may participate in the regulation of some immune pathways and immune functions. CONCLUSION: Let-7c-5p has been proved to suppress HCC by down-regulating immune-related CDCA8, which will help understand the pathogenesis of HCC and develop drugs for its treatment.

High level of tumor marker CA19-9 returned to normal after cholecystectomy in calculous cholecystitis patients.

BACKGROUND: High serum CA19-9 is usually caused by pancreaticobiliary malignancies, but it has also been found in a tiny minority of calculous cholecystitis patients. AIMS: To clarify the relationship between calculous cholecystitis and serum CA19-9. METHODS: Clinical data of calculous cholecystitis patients with high serum CA19-9 (high group, n = 20) and normal serum CA19-9 (normal group, n = 40) who underwent cholecystectomy were analyzed. Serum CA19-9 of high group were followed-up and gallbladder specimens were analyzed by immunohistochemistry. RESULTS: Serum CA19-9 in the high group ranged from 105 to 1635 U/ml, of which 30% exceeded 1000 U/ml. Follow-up results showed that 20 patient's serum CA19-9 returned to normal after cholecystectomy, including 4 closely followed-up patients whose serum CA19-9 recovered within one month. Immunohistochemical results revealed that CA19-9 was mildly positive only in mucosal epithelial cells in the normal group, but positive in mucosal epithelial cells, vascular endothelial cells, and intercellular substances in the high group, accounting for high serum CA19-9. CONCLUSION: Serum CA19-9 is proved to be associated with calculous cholecystitis for the first time, so that clinicians should consider calculous cholecystitis associated CA19-9 elevation in the clinic practice besides other CA19-9 related diseases.

Revealing evolutionary constraints on proteins through sequence analysis.

Statistical analysis of alignments of large numbers of protein sequences has revealed "sectors" of collectively coevolving amino acids in several protein families. Here, we show that selection acting on any functional property of a protein, represented by an additive trait, can give rise to such a sector. As an illustration of a selected trait, we consider the elastic energy of an important conformational change within an elastic network model, and we show that selection acting on this energy leads to correlations among residues. For this concrete example and more generally, we demonstrate that the main signature of functional sectors lies in the small-eigenvalue modes of the covariance matrix of the selected sequences. However, secondary signatures of these functional sectors also exist in the extensively-studied large-eigenvalue modes. Our simple, general model leads us to propose a principled method to identify functional sectors, along with the magnitudes of mutational effects, from sequence data. We further demonstrate the robustness of these functional sectors to various forms of selection, and the robustness of our approach to the identification of multiple selected traits.

FoxH1 mediates a Grg4 and Smad2 dependent transcriptional switch in Nodal signaling during Xenopus mesoderm development.

In the vertebrate blastula and gastrula the Nodal pathway is essential for formation of the primary germ layers and the organizer. Nodal autoregulatory feedback potentiates signaling activity, but mechanisms limiting embryonic Nodal ligand transcription are poorly understood. Here we describe a transcriptional switch mechanism mediated by FoxH1, the principle effector of Nodal autoregulation. FoxH1 contains a conserved engrailed homology (EH1) motif that mediates direct binding of groucho-related gene 4 (Grg4), a Groucho family corepressor. Nodal-dependent gene expression is suppressed by FoxH1, but enhanced by a FoxH1 EH1 mutant, indicating that the EH1 motif is necessary for repression. Grg4 blocks Nodal-induced mesodermal gene expression and Nodal autoregulation, suggesting that Grg4 limits Nodal pathway activity. Conversely, blocking Grg4 function in the ectoderm results in ectopic expression of Nodal target genes. FoxH1 and Grg4 occupy the Xnr1 enhancer, and Grg4 occupancy is dependent on the FoxH1 EH1 motif. Grg4 occupancy at the Xnr1 enhancer significantly decreases with Nodal activation or Smad2 overexpression, while FoxH1 occupancy is unaffected. These results suggest that Nodal-activated Smad2 physically displaces Grg4 from FoxH1, an essential feature of the transcriptional switch mechanism. In support of this model, when FoxH1 is unable to bind Smad2, Grg4 occupancy is maintained at the Xnr1 enhancer, even in the presence of Nodal signaling. Our findings reveal that FoxH1 mediates both activation and repression of Nodal gene expression. We propose that this transcriptional switch is essential to delimit Nodal pathway activity in vertebrate germ layer formation.

Successful use of partial aneurysmectomy and repair approach for managing complications of arteriovenous fistulas and grafts.

OBJECTIVE: Arteriovenous fistulas and grafts may often be associated with localized complications related to aneurysms/pseudoaneurysms, buttonholes, or structural defects that require proper management to ensure continued access functionality for hemodialysis. Partial aneurysmectomy and repair (PAR) is a targeted surgical approach specifically designed for managing these complications. The basic concepts of PAR include resecting unhealthy or excessive tissue over an access, reconstructing the vascular access lumen using in situ vascular wall or tissue when possible, and closing overlying skin with healthy margins to promote reliable healing. This report analyzes the clinical outcomes of PAR in a large clinical series. METHODS: The demographic and outcome data of patients who underwent PARs at an ambulatory surgery center from 2009 to 2016 were collected and analyzed. RESULTS: A total of 220 PAR operations were performed in 209 patients, of which 185 had fistulas and 24 had grafts. In the fistula group, 11 patients underwent subsequent staged aneurysm repairs. Comparing the fistula group (n = 185) vs the graft group (n = 24): men were 63% vs 29%, the mean age was 60.1 ± 14.8 vs 63.9 ± 16.0 years, diabetic patients were 54% vs 75%, the mean age of the accesses at the time of repair was 5.3 ± 3.2 vs 5.0 ± 4.0 years, the upper arm accesses were 69% vs 88%, the forearm accesses were 31% vs 12%, and the mean follow-up was 27.9 ± 21.9 vs 14.0 ± 11.6 months. A pneumatic tourniquet was used during 81% of the fistula and 42% of the graft operations. Dialysis catheters were required in 2% of the patients in the fistula group and 4% in the graft group to continue hemodialysis. After repair operations, the primary patency, assisted primary patency, and secondary patency rates of the whole access conduit for the fistula group were 45%, 96%, and 98% at 1 year; 28%, 91%, and 96% at 2 years; and 19%, 87%, and 95% at 3 years, respectively. The same patency rates of the graft group were 31%, 70%, and 96% at 6 months and 10%, 57%, and 96% at 1 year, respectively. Two fistulas and one graft were lost ≤30 days postoperatively. CONCLUSIONS: PAR is a reliable approach for managing localized arteriovenous access complications related to aneurysms/pseudoaneurysms, buttonholes, or structural defects. Given its simplicity and reliability, we recommend PAR as a first-line choice for managing these complications of arteriovenous fistulas and a choice in selected arteriovenous graft patients.

Basilic elevation transposition may improve the clinical outcomes for superficialization of basilic arteriovenous fistula veins.

OBJECTIVE: Basilic vein arteriovenous fistulas are an important and common option for hemodialysis access and require superficialization before use. Various superficialization techniques have been employed, such as basilic tunnel transposition (BTT), basilic elevation, and basilic elevation transposition (BET). Each technique may have advantages and disadvantages, and there have been few reports directly comparing the outcomes of these techniques. This report compares the clinical outcomes of BET vs BTT performed by a single operator and discusses some technical considerations derived from this study and the literature. METHODS: The demographic and outcome data of patients who underwent second-stage basilic vein transposition at an ambulatory surgery center from February 2009 to January 2016 were collected and analyzed. RESULTS: Of the 99 patients identified, 53% were male and 64% were diabetic; the mean age was 61 ± 16 years; 27 had BTT and 72 had BET; the mean follow-up was 26.2 ± 20.5 (range, 1-83) months. The primary patency, assisted primary patency, and secondary patency rates of the whole fistula conduit were 26%, 91%, and 100% for the BTT group and 46%, 98%, 100% for the BET group at 1 year and 21%, 80%, 94% for the BTT group and 38%, 98%, 98% for the BET group at 2 years. The primary patency rate of the basilic vein (segment of the fistula conduit superficialized by transposition) at 1 year was significantly lower for the BTT group vs the BET group (26% vs 61%; P = .004). The average number of percutaneous interventions required for the basilic vein was significantly more for the BTT group vs the BET group (1.5 ± 1.3 vs 0.6 ± 1.0/access-year; P = .007). Based on a Cox regression analysis, the surgical techniques were the only clinical factor that significantly affected the basilic vein primary patency (hazard ratio of 2.28 in favor of BET over BTT; 95% confidence interval, 1.25-4.14; P = .007). CONCLUSIONS: BET is a reliable approach that yields a high cumulative fistula survival rate. Compared with BTT, BET is associated with improved basilic vein primary patency and reduced need for endovascular interventions.

Entropy Production of Nanosystems with Time Scale Separation.

Energy flows in biomolecular motors and machines are vital to their function. Yet experimental observations are often limited to a small subset of variables that participate in energy transport and dissipation. Here we show, through a solvable Langevin model, that the seemingly hidden entropy production is measurable through the violation spectrum of the fluctuation-response relation of a slow observable. For general Markov systems with time scale separation, we prove that the violation spectrum exhibits a characteristic plateau in the intermediate frequency region. Despite its vanishing height, the plateau can account for energy dissipation over a broad time scale. Our findings suggest a general possibility to probe hidden entropy production in nanosystems without direct observation of fast variables.

Pneumatic tourniquet for surgical procedures of hemodialysis vascular access.

Pneumatic tourniquet has been frequently utilized in various surgical specialties to facilitate surgical procedures on the extremities. However, its use for surgical procedures of hemodialysis access has been limited to some surgeons in the United States and often confined to the hospital settings under general anesthesia or regional nerve block. We have successfully employed a pneumatic tourniquet system for surgical procedures of hemodialysis access under conscious sedation and local anesthesia in an outpatient setting. Because prolonged tourniquet inflation is associated with ischemic pain and other potential complications, we have limited the continuous inflation time to <30 minutes. Our recent data from 550 surgical procedures of hemodialysis access have emphasized that pneumatic tourniquet use is well tolerated under conscious sedation and not associated with significant adverse events. These and other reported data suggest that pneumatic tourniquet can reduce procedure time, minimize required dissection, reduce vascular trauma by eliminating vascular clamps and potentially improve the outcomes of surgical procedures of hemodialysis access. These advantages may be translated into cost savings for hemodialysis access care. This review discusses practical issues of pneumatic tourniquet use and its applications in surgical procedures of hemodialysis access.

The Venous Window Needle Guide, a hemodialysis cannulation device for salvage of uncannulatable arteriovenous fistulas.

BACKGROUND: Arteriovenous fistulas (AVFs) are recommended for hemodialysis access when possible. A noncannulatable but otherwise well functioning AVF leads to prolonged catheter dependency and frustration for the patient and the renal health care provider team. Difficult cannulation patients include obese individuals in whom cannulation sites are too deep, and others with vein segments that are short, tortuous, or otherwise difficult to palpate. The Venous Window Needle Guide for Salvage of AV Fistulae (SAVE) trial was designed to evaluate the efficacy and safety of the Venous Window Needle Guide (VWING; Vital Access Corp, Salt Lake City, Utah) device for salvage of such noncannulatable AVFs that are otherwise functional. METHODS: The SAVE study included patients with an established and otherwise mature AVF, in whom an additional procedure would otherwise be necessary to establish reliable cannulation. The VWING is a single-piece titanium device that allows repeated access of an AVF through a single puncture site (buttonhole technique). Inclusion criteria included mature AVFs 6.0 to 15.0 mm in depth with multiple failed attempts at cannulation or where the access could not be palpated. The devices were implanted subcutaneously and sutured to the anterior wall of the mature fistula. Study end points were reliable and successful cannulation and avoidance of adverse events during the 6-month follow-up, implant technical success, and clinical cannulation success. RESULTS: Enrollment included 54 patients at 11 trial sites with implantation of 82 VWING devices. Body mass index was 26 to 50 (median, 36), 40 (74%) patients were female, and age was 17 to 84 (median, 59) years. Forty (74%) individuals were diabetic. Thirty-three (61%) patients were white, 16 (30%) black, and 10 (18%) patients were Hispanic, Pacific Islander, or Native American. Three patients were excluded from data analysis for reasons unrelated to the device. Successful AVF access was achieved using the VWING in 49 (96%) of the 51 patients evaluated. The rate of device-related serious adverse events was 0.31 per patient-year; each event was resolved leaving the AVF functional. The rates of sepsis and study-related interventions were 0.04 and 0.65 per patient-year, respectively. There were no study-related deaths. One device was removed because of infection. The AVF survival rate at 6 months was 100%. The total number of study days was 9497 and the estimated number of device cannulations was 4238. CONCLUSIONS: The VWING was safe and effective in facilitating AVF cannulation for patients with an otherwise mature but noncannulatable fistula. Successful AVF access was achieved using the VWING in 49 (96%) of the 51 patients evaluated. The AVF survival rate at 6 months was 100%.

Aging aggravates liver fibrosis through downregulated hepatocyte SIRT1-induced liver sinusoidal endothelial cell dysfunction.

BACKGROUND: Aging increases the susceptibility to chronic liver diseases and hastens liver fibrosis deterioration, but the underlying mechanisms remain partially understood. The aim of this study was to investigate the effect of aging and chronic liver diseases on hepatocyte Sirtuin 1 (SIRT1) and LSECs and their contribution to liver fibrosis pathogeneses. METHODS: Young (8-12 wk) and aged (18-20 mo) mice were subjected to carbon tetrachloride-induced liver fibrosis. Primary HSCs and LSECs were isolated and cocultured for in vitro experiments. Liver tissues and blood samples from healthy controls and patients with liver fibrosis were analyzed. RESULTS: Downregulated hepatocytes SIRT1 in aged mice increased high mobility group box 1 acetylation, cytoplasmic translocation, and extracellular secretion, causing LSECs dysfunction by means of the toll-like receptor 4/AK strain transforming (AKT)/endothelial nitric oxide synthase pathway, ultimately activating HSCs and increasing susceptibility to liver injury and fibrosis. Adeno-associated virus-mediated overexpression of SIRT1 in hepatocytes suppressed the abovementioned alterations and attenuated carbon tetrachloride-induced liver injury and fibrosis in liver fibrosis mice, and there were no significant differences in liver injury and fibrosis indicators between young and aged mice after SIRT1 overexpression treatment. In vitro experiments demonstrated that SIRT1 overexpression and endothelial nitric oxide synthase agonist YC-1 improved LSECs function and inhibited HSCs activation, mediated by nitric oxide. Similarly, downregulated hepatocytes SIRT1 and LSECs dysfunction were observed in the livers of aged individuals compared to young individuals and were more pronounced in aged patients with liver fibrosis. CONCLUSIONS: Aging aggravates liver fibrosis through downregulated hepatocytes SIRT1-induced LSECs dysfunction, providing a prospective curative approach for preventing and treating liver fibrosis.

A Multicentric Study of Different Methods of Open Surgical Cerebral Revascularization for Internal Carotid Artery Orifice Stenosis.

To analyze the long-term results of transposition of the internal carotid artery (ICA) into the lateral wall of the external carotid artery (ECA) in the presence of hemodynamically significant stenosis of the ICA. During the period from 3.10.2017 to 28.12.2020, 784 patients with isolated hemodynamically significant ICA orifice stenosis were included in the present retrospective multicentric open comparative study "Russian Birch." Depending on the implemented surgical technique, groups were formed: group 1 (n = 517) - eversion carotid endarterectomy (eCEA); group 2 (n = 193) classic CEA with implantation of a xenopericardium patch treated with di-epoxy compounds; group 3 (n = 74) - transposition of the ICA into the lateral wall of the ECA. Transposition of the ICA into the lateral wall of the ECA is performed as follows. The common carotid artery, ECA, and ICA are isolated and then they are clamped with vascular clamps. At the same time, the ICA and ECA are clamped 4 cm above the orifice. The ICA is cut 2.5 cm above the orifice. Then the section of the ICA with local stenosis in the orifice is sutured with a polypropylene suture. At the same time, the redundant nonfunctioning ICA stump is not resected due to the fact that there are receptors of the carotid sinus at the ICA orifice. Thus, such manipulation may damage the sinus, causing arterial hypertension that is difficult to control in the postoperative period. Then, in the lateral wall of the ECA 2.5 cm above the orifice, a 0.5 cm diameter round hole is formed using a scalpel and angled vascular scissors. Then an end-to-side anastomosis between the severed section of the ICA and the rounded opening formed in the lateral wall of the ECA is performed using a polypropylene suture. Vascular clamps are removed and blood flow is started. No complications were detected in the hospital postoperative period. No adverse cardiovascular events were registered in group 3 in the long-term follow-up period. The group of classic CEA with implantation of a xenopericardium patch treated with di-epoxy compounds showed the highest number of fatal outcomes from acute cerebrovascular accident (CVA) (Group 1: 0.2%, n = 1; group 2: 2.6%; n = 5; p = 0.008); nonfatal ischemic CVA (group 1: 0.6%, n = 3; group 2: 14.0%, n = 27; p < 0.0001); ICA restenosis (more than 60%) requiring a repeat revascularization (group 1: 0.8%, n = 4; group 2: 16.6%, n = 32; p < 0.0001). The cause of all CVAs after classical CEA was restenosis of the ICA due to neointimal hyperplasia; after eversion CEA and progression of atherosclerosis. The composite end point was statistically more frequent after classical CEE with plasty of the reconstruction area with a diepoxy-treated xenopericardium patch (group 1: 1.0%, n = 5; group 2: 17.7%, n = 33; p < 0.0001). When analyzing the survival curves free of ICA restenosis, it was determined that the overwhelming number of all ICA restenosis requiring revascularization in the group of classical CEA with implantation of a diepoxy-treated xenopericardium patch is diagnosed as early as 6 months after surgery. In the group of eversion CEA, the loss of the vessel lumen is most often visualized more than a year after the intervention. When comparing the survival curves (Logrank test), it was determined that restenosis of the ICA develops statistically more frequently (p < 0.0001) after classical CEA with implantation of a diepoxytreated xenopericardium patch. Transposition of the ICA into the lateral wall of the ECA is not accompanied by the risk of ICA restenosis due to the absence of inflammation of the internal artery wall after endarterectomy. Thus, this technique can be an alternative to CEA and be routinely used in case of local hemodynamically significant stenosis of the ICA orifice. Classical CEA with patch implantation is the least preferable operation due to the high risk of ICA restenosis in the mid-term and long-term follow-up.

Transradial approach for cardiovascular interventions and its implications for hemodialysis vascular access.

Because of its advantages, the transradial approach for cardiovascular interventions has gained significant popularity. However, this approach can be associated with radial artery thrombosis and occlusion. The complication generates a major concern for its potential impact on the future creation of an arteriovenous hemodialysis access. The issue gains more importance as a significant number of patients with cardiovascular disease suffer from underlying chronic kidney disease (CKD) and might need an arteriovenous access for hemodialysis therapy. In this context, the preservation of the arterial system is of equal importance to the frequently highlighted venous conservation for the successful creation of an arteriovenous access. It is for this reason that the Fistula First Breakthrough Initiative recommends avoiding the use of the radial artery for performing percutaneous interventions in patients with advanced CKD. Furthermore, there is scarce clinical data and publication regarding the impact of transradial approach on hemodialysis access. Is it possible to utilize the potential benefits and minimize the potential risks of transradial approach in chronic kidney disease patients? On the basis of current knowledge, this review discusses related issues of transradial approach to raise awareness and understanding, which are essential to proper caring of CKD patients undergoing cardiovascular interventions.

Surgical management of cephalic arch occlusive lesions: are there predictors for outcomes?

Cephalic arch lesions are common cause for dysfunction of brachiocephalic arteriovenous fistulas. For lesions resistant or not amenable to endovascular interventions, we used a term "cephalic arch occlusive lesions" (CAO) that included cephalic arch total occlusion, frequently recurrent stenosis (requiring angioplasty in <3-month intervals), high-grade elastic stenosis (residual stenosis >50% after angioplasty), or other lesions not amenable to endovascular interventions. Herein, we report 40 patients who underwent surgical revisions for total occlusions (17/40), frequently recurrent stenosis (17/40), high-grade elastic stenosis (5/40), and zigzag stenosis (1/40). The revisions included cephalic transposition and venovenostomy (CTV = 37/40), basilic transposition and venovenostomy (1/40), stenotic segment resection (1/40), and cephalic-jugular vein bypass graft (1/40). At 12-month post-CTV, the primary patency of the transposed cephalic vein, the fistula assisted primary and secondary patency rates were 25%, 82% and 97%, respectively. Notably, pre-CTV angioplasty of the proximal cephalic vein was the only significant predictor for the low primary patency rate (hazard ratio 4.5, p = 0.002). Accordingly, the primary patency rates were 12% and 58% in patients with and without pre-CTV angioplasty, respectively. In summary, surgical interventions are effective in salvaging fistulas complicated with CAO. Importantly, pre-CTV angioplasty of the proximal cephalic vein might adversely affect the outcome of CTV.

Dilator-assisted banding for managing complications associated with excessive hemodialysis access flow.

Excessive hemodialysis access flow can be associated with serious complications, such as ischemic steal syndrome and heart failure. Among the therapeutic approaches, endoluminal balloon-guided banding has the advantage of being minimally invasive. However, it requires fluoroscopic guidance. We here report a simpler approach, Dilator-assisted Banding (DAB), in which over-the-wire vascular dilators of known diameters are used as endoluminal-guides to achieve precision banding with or without fluoroscopic guidance. The dilators used are 10, 12, and 14 French, corresponding to 3.3, 4.0, and 4.7 mm in diameter, respectively. Of the seven treated patients with ischemic steal syndrome, three were males, mean age was 67.7 ± 16.3 years, five were diabetics, all were hypertensive, five had fistulas, and two had grafts. Mean age of hemodialysis accesses was 17.2 ± 8.4 months. Three patients had banding without fluoroscopic guidance, including two performed during fistula vein superficialization and basilic vein transposition. With follow-up of 2-12 months, all hemodialysis accesses remained functional. Six patients had complete resolution and one reported marked improvement of ischemic symptoms. In summary, DAB is a simple, effective, and economical flow-reduction alternative for managing ischemic steal syndrome and potentially other complications associated with excessive access flows. In addition, it can be safely performed without fluoroscopic guidance.

Radial artery harvest: a potential cause of arteriovenous access-associated hand ischemia.

Hand ischemia has multiple causes. In this article, we report an additional factor that can induce hand ischemia in hemodialysis patients. A 64-year-old white man with coronary artery disease underwent a coronary artery bypass graft procedure using the left radial artery as the bypass graft. Several months later, a left extremity Gracz fistula was created for arteriovenous access. Ever since dialysis was performed via the fistula the patient has experienced a cold hand and pain during dialysis that was somewhat relieved by wearing a woolen glove while on dialysis. Absence of the radial artery in the context of an ipsilateral arteriovenous access was highlighted as a possible etiology. A complete arteriography to determine the presence of stenoses, distal arteriopathy, and true steal was recommended, but the patient refused to undergo any investigation or procedure and instead decided to continue wearing the glove during the treatment. A plan for close follow-up and possible interventions in the event of worsening pain/ulceration was agreed upon. Radial artery harvest can result in hand ischemia if an ipsilateral arteriovenous access is created. We suggest that the contralateral extremity should be considered if an arteriovenous access is required to minimize this risk of this phenomenon.

Partial aneurysmectomy is effective in managing aneurysm-associated complications of arteriovenous fistulae for hemodialysis: case series and literature review.

Fistula aneurysms are commonly seen and usually do not affect fistula function for hemodialysis. However, these aneurysms are associated with complications that increase the risk of fistula bleeding and loss. The common feature of these complications is that the diseased tissues usually affect a localized area of an aneurysm. Accordingly, we developed a targeted intervention "partial aneurysmectomy" in which only the diseased area was resected. In this report, we sought to examine the outcomes of partial aneurysmectomies performed in 36 cases for the following indications: active bleeding (14%), skin scab plus fistula defect in imminent danger of bleeding (33%), skin necrosis and erosion (28%), and thin-walled aneurysm in danger of rupture (25%). Postoperatively, all patients continued hemodialysis using their fistulae. During 2-18-month follow-up, all fistulae but one were functional and required no intervention on the repaired areas. At 6 months, the aneurysm primary patency, fistula primary patency, and fistula-assisted primary patency rates were 97%, 56%, and 97%, respectively. In conclusion, partial aneurysmectomy is a simple and effective intervention for managing aneurysm-associated complications and preserving fistula function. Owing to its advantages over other interventions, we recommend partial aneurysmectomy as first-line choice for managing aneurysm-associated complications.