Obstructive sleep apnea intensifies stroke severity following middle cerebral artery occlusion

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a sleep disorder caused by transient obstruction of the upper airway and results in intermittent hypoxia, sleep fragmentation, sympathetic nervous system activation, and arousal which can have an adverse effect on cardiovascular disease. It is theorized that OSA might intensify stroke injury. Our goal here was to develop a new model of experimental OSA and test its ability to aggravate behavioral and morphological outcomes following transient brain ischemia/reperfusion.

METHODS

We used a 3D printed OSA device to expose C57BL6 mice to 3 h of OSA (obstructive apnea index of 20 events per hour) for three days. These mice were then subjected to ischemia/reperfusion using the middle cerebral artery occlusion model (MCAO) stroke and examined for overall survival, infarct size and neurological scoring.

RESULTS

We found that OSA transiently decreased respiration and reduced oxygen saturation with bradycardia and tachycardia typical of human responses during apneic events. Brain injury from MCAO was significantly increased by OSA as measured by infarct size and location as well as by intensification of neurological deficits; mortality following MCAO was also increased in OSA animals.

CONCLUSIONS

Our findings suggest that our new model of OSA alters respiratory and cardiovascular physiological functions and is associated with enhanced ischemia/reperfusion mediated injury in our non-invasive, OSA intensified model of stroke.

Autologous Adipose Tissue-Derived Mesenchymal Stem Cells Introduced by Biliary Stents or Local Immersion in Porcine Bile Duct Anastomoses

Biliary complications (strictures and leaks) represent major limitations in living donor liver transplantation. Mesenchymal stem cells (MSCs) are a promising modality to prevent biliary complications because of immunosuppressive and angiogenic properties. Our goal was to evaluate the safety of adipose-derived MSC delivery to biliary anastomoses in a porcine model. Secondary objectives were defining the optimal method of delivery (intraluminal versus extraluminal) and to investigate MSC engraftment, angiogenesis, and fibrosis. Pigs were divided into 3 groups. Animals underwent adipose collection, MSC isolation, and expansion. Two weeks later, animals underwent bile duct transection, reanastomosis, and stent insertion. Group 1 received plastic stents wrapped in unseeded Vicryl mesh. Group 2 received stents wrapped in MSC-seeded mesh. Group 3 received unwrapped stents with the anastomosis immersed in an MSC suspension. Animals were killed 1 month after stent insertion when cholangiograms and biliary tissue were obtained. Serum was collected for liver biochemistries. Tissue was used for hematoxylin-eosin and trichrome staining and immunohistochemistry for MSC markers (CD44 and CD34) and for a marker of neoangiogenesis (CD31). There were no intraoperative complications. One pig died on postoperative day 3 due to acute cholangitis. All others recovered without complications. Cholangiography demonstrated no biliary leaks and minimal luminal narrowing. Surviving animals exhibited no symptoms, abnormal liver biochemistries, or clinically significant biliary stricturing. Group 3 showed significantly greater CD44 and CD34 staining, indicating MSC engraftment. Fibrosis was reduced at the anastomotic site in group 3 based on trichrome stain. CD31 staining of group 3 was more pronounced, supporting enhanced neoangiogenesis. In conclusion, adipose-derived MSCs were safely applied to biliary anastomoses. MSCs were locally engrafted within the bile duct and may have beneficial effects in terms of fibrosis and angiogenesis.

Brain Endothelial Cells Release Apical and Basolateral Microparticles in Response to Inflammatory Cytokine Stimulation: Relevance to Neuroinflammatory Stress?

Microparticles (MP) are regarded both as biomarkers and mediators of many forms of pathology, including neurovascular inflammation. Here, we characterized vectorial release of apical and basolateral MPs (AMPs and BMPs) from control and TNF-α/IFN-γ treated human brain endothelial monolayers, studied molecular composition of AMPs and BMPs and characterized molecular pathways regulating AMP and BMP release. The effects of AMPs and BMPs on blood-brain barrier properties and human brain microvascular smooth muscle tonic contractility in vitro were also evaluated. We report that human brain microvascular endothelial cells release MPs both apically and basolaterally with both AMP and BMP release significantly increased following inflammatory cytokine challenge (3.5-fold and 3.9-fold vs. control, respectively). AMPs and BMPs both carry proteins derived from parent cells including those in BBB junctions (Claudin−1, −3, −5, occludin, VE-cadherin). AMPs and BMPs represent distinct populations whose release appears to be regulated by distinctly separate molecular pathways, which depend on signaling from Rho-associated, coiled-coil containing protein kinase (ROCK), calpain as well as cholesterol depletion. AMPs and BMPs modulate functions of neighboring cells including BBB endothelial solute permeability and brain vascular smooth muscle contractility. While control AMPs enhanced brain endothelial barrier, cytokine-induced AMPs impaired BBB. Cytokine-induced but not control BMPs significantly impaired human brain smooth muscle contractility as early as day 1. Taken together these results indicate that AMPs and BMPs may contribute to neurovascular inflammatory disease progression both within the circulation (AMP) and in the brain parenchyma (BMP).

Antibiotics in 3D-printed implants, instruments and materials: benefits, challenges and future directions

3D printing is an additive manufacturing technology, which permits innovative approaches for incorporating antibiotics into 3D printed constructs. Antibiotic-incorporating applications in medicine have included medical implants, prostheses, along with procedural and surgical instruments. 3D-printed antibiotic-impregnated devices offer the advantages of increased surface area for drug distribution, sequential layers of antibiotics produced through layer-by-layer fabrication, and the ability to rapidly fabricate constructs based on patient-specific anatomies. To date, fused deposition modeling has been the main 3D printing method used to incorporate antibiotics, although inkjet and stereolithography techniques have also been described. This review offers a state-of-the-art summary of studies that incorporate antibiotics into 3D-printed constructs and summarizes the rationale, challenges, and future directions for the potential use of this technology in patient care.

Potential therapeutic roles of stem cells in ischemia-reperfusion injury

Ischemia-reperfusion injury (I/RI), produced by an initial interruption of organ blood flow and its subsequent restoration, contributes significantly to the pathophysiologies of stroke, myocardial infarction, renal I/RI, intestinal I/RI and liver I/RI, which are major causes of disability (including transplant failure) and even mortality. While the restoration of blood flow is required to restore oxygen and nutrient requirements, reperfusion often triggers local and systemic inflammatory responses and subsequently elevate the ischemic insult where the duration of ischemia determines the magnitude of I/RI damage. I/RI increases vascular leakage, changes transcriptional and cell death programs, drives leukocyte entrapment and inflammation and oxidative stress in tissues. Therapeutic approaches which reduce complications associated with I/RI are desperately needed to address the clinical and economic burden created by I/RI. Stem cells (SC) represent ubiquitous and uncommitted cell populations with the ability to self-renew and differentiate into one or more developmental 'fates'. Like immune cells, stem cells can home to and penetrate I/R-injured tissues, where they can differentiate into target tissues and induce trophic paracrine signaling which suppress injury and maintain tissue functions perturbed by ischemia-reperfusion. This review article summarizes the present use and possible protective mechanisms underlying stem cell protection in diverse forms of ischemia-reperfusion.

3D Printing for Bio-Synthetic Biliary Stents

Three-dimensional (3D) printing is an additive manufacturing method that holds great potential in a variety of future patient-specific medical technologies. This project validated a novel crosslinked polyvinyl alcohol (XL-PVA) 3D printed stent infused with collagen, human placental mesenchymal stem cells (PMSCs), and cholangiocytes. The biofabrication method in the present study examined 3D printing and collagen injection molding for rapid prototyping of customized living biliary stents with clinical applications in the setting of malignant and benign bile duct obstructions. XL-PVA stents showed hydrophilic swelling and addition of radiocontrast to the stent matrix improved radiographic opacity. Collagen loaded with PMSCs contracted tightly around hydrophilic stents and dense choloangiocyte coatings were verified through histology and fluorescence microscopy. It is anticipated that design elements used in these stents may enable appropriate stent placement, provide protection of the stent-stem cell matrix against bile constituents, and potentially limit biofilm development. Overall, this approach may allow physicians to create personalized bio-integrating stents for use in biliary procedures and lays a foundation for new patient-specific stent fabrication techniques.

3D printing of surgical hernia meshes impregnated with contrast agents: in vitro proof of concept with imaging characteristics on computed tomography

BACKGROUND

Selected medical implants and other 3D printed constructs could potentially benefit from the ability to incorporate contrast agents into their structure. The purpose of the present study is to create 3D printed surgical meshes impregnated with iodinated, gadolinium, and barium contrast agents and characterize their computed tomography (CT) imaging characteristics. Commercial fused deposition layering 3D printing was used to construct surgical meshes impregnated with imaging contrast agents in an in vitro model. Polycaprolactone (PCL) meshes were printed containing iodinated, gadolinium, or barium contrast; control PCL meshes without contrast were also fabricated. The three different contrast agents were mixed with PCL powder and directly loaded into the 3D printer. CT images of the three contrast-containing meshes and the control meshes were acquired and analyzed using small elliptical regions of interest to record the Hounsfield units (HU) of each mesh. Subsequently, to test their solubility and sustainability, the contrast-containing meshes were placed in a 37 °C agar solution for 7 days and imaged by CT at days 1, 3 and 7.

RESULTS

All 3D printed meshes were visible on CT. Iodinated contrast meshes had the highest attenuation (2528 mean HU), significantly higher than both and gadolinium (1178 mean HU) and barium (592 mean HU) containing meshes. Only barium meshes sustained their visibility in the agar solution; the iodine and gadolinium meshes were poorly perceptible and had significantly lower mean HU compared to their pre-agar solution imaging, with iodine and gadolinium present in the adjacent agar at day 7 CT.

CONCLUSION

3D prints embedded with contrast materials through this method displayed excellent visibility on CT; however, only barium mesh maintained visibility after 7 days incubation on agar at human body temperature. This method of 3D printing with barium may have potential applications in a variety of highly personalized and CT visible medical devices.

High-throughput scaffold-free microtissues through 3D printing

BACKGROUND

Three-dimensional (3D) cell cultures and 3D bioprinting have recently gained attention based on their multiple advantages over two-dimensional (2D) cell cultures, which have less translational potential to recapitulate human physiology. 3D scaffold supports, cell aggregate systems and hydrogels have been shown to accurately mimic native tissues and support more relevant cell-cell interactions for studying effects of drugs and bioactive agents on cells in 3D. The development of cost-effective, high-throughput and scaffold-free microtissue assays remains challenging. In the present study, consumer grade 3D printing was examined as a fabrication method for creation of high-throughput scaffold-free 3D spheroidal microtissues.

RESULTS

Consumer grade 3D printing was capable of forming 96-well cell culture inserts to create scaffold-free microtissues in liquid suspensions. The inserts were seeded with human glioblastoma, placental-derived mesenchymal stem cells, and intestinal smooth muscle cells. These inserts allowed for consistent formation of cell density-controllable microtissues that permit screening of bioactive agents.

CONCLUSION

A variety of different cell types, co-cultures, and drugs may be evaluated with this 3D printed microtissue insert. It is suggested that the microtissue inserts may benefit 3D cell culture researchers as an economical assay solution with applications in pharmaceuticals, disease modeling, and tissue-engineering.

Three-Dimensional Printing of Cell Exclusion Spacers (CES) for Use in Motility Assays

PURPOSE

Cell migration/invasion assays are widely used in commercial drug discovery screening. 3D printing enables the creation of diverse geometric restrictive barrier designs for use in cell motility studies, permitting on-demand assays. Here, the utility of 3D printed cell exclusion spacers (CES) was validated as a cell motility assay.

METHODS

A novel CES fit was fabricated using 3D printing and customized to the size and contour of 12 cell culture plates including 6 well plates of basal human brain vascular endothelial (D3) cell migration cells compared with 6 well plates with D3 cells challenged with 1uM cytochalasin D (Cyto-D), an F-actin anti-motility drug. Control and Cyto-D treated cells were monitored over 3 days under optical microscopy.

RESULTS

Day 3 cell migration distance for untreated D3 cells was 1515.943μm ± 10.346μm compared to 356.909μm ± 38.562μm for the Cyt-D treated D3 cells (p < 0.0001). By day 3, untreated D3 cells reached confluency and completely filled the original voided spacer regions, while the Cyt-D treated D3 cells remained significantly less motile.

CONCLUSIONS

Cell migration distances were significantly reduced by Cyto-D, supporting the use of 3D printing for cell exclusion assays. 3D printed CES have great potential for studying cell motility, migration/invasion, and complex multi-cell interactions.

Antibacterial and antibiofouling clay nanotube-silicone composite

Introduction

Invasive medical devices are used in treating millions of patients each day. Bacterial adherence to their surface is an early step in biofilm formation that may lead to infection, health complications, longer hospital stays, and death. Prevention of bacterial adherence and biofilm development continues to be a major healthcare challenge. Accordingly, there is a pressing need to improve the anti-microbial properties of medical devices.

Materials and Methods

Polydimethylsiloxane (PDMS) was doped with halloysite nanotubes (HNTs), and the PDMS-HNT composite surfaces were coated with PDMS-b-polyethylene oxide (PEO) and antibacterials. The composite material properties were examined using SEM, energy dispersive spectroscopy, water contact angle measurements, tensile testing, UV-Vis spectroscopy, and thermal gravimetric analysis. The antibacterial potential of the PDMS-HNT composites was compared to commercial urinary catheters using cultures of E. coli and S. aureus. Fibrinogen adsorption studies were also performed on the PDMS-HNT-PEO composites.

Results

HNT addition increased drug load during solvent swelling without reducing material strength. The hydrophilic properties provided by PEO were maintained after HNT addition, and the composites displayed protein-repelling properties. Additionally, composites showed superiority over commercial catheters at inhibiting bacterial growth.

Conclusion

PDMS-HNT composites showed superiority regarding their efficacy at inhibiting bacterial growth, in comparison to commercial antibacterial catheters. Our data suggest that PDMS-HNT composites have potential as a coating material for anti-bacterial invasive devices and in the prevention of institutional-acquired infections.

Personalized Bioactive Nasal Supports for Postoperative Cleft Rhinoplasty

PURPOSE

After cleft lip and palate surgical procedures, patients often need nostril supports to help the reconstructed nostrils retain their shape during healing. Many postoperative nasal stents use a one-size-fits-all approach, in which a standard rubber tube retainer is trimmed and used to support the healing nares. The purpose of this study was to examine photogrammetry and 3-dimensional (3D) printing as a fabrication tool for postoperative patient-specific nasal supports that can be loaded with bioactive agents for localized delivery.

MATERIALS AND METHODS

A "normal" right nostril injection mold was prepared from a left-sided unilateral cleft defect, and the negative-space impression was modeled using a series of photographs taken at different rotation angles with a commercial mobile phone camera. These images were "stitched" together using photogrammetry software, and the computer-generated models were reflected, joined, and digitally sculpted to generate hollow bilateral supports. Three-dimensional prints were coated with polyvinylpyrrolidone-penicillin and validated for their ability to inhibit Escherichia coli using human blood agar diffusion assays.

RESULTS

The results showed that our approach had a high level of contour replication and the antibiotic coating was able to inhibit bacterial growth with a mean zone of inhibition of 15.15 ± 0.99 mm (n = 9) (P < .0001) in disc diffusion assays.

CONCLUSIONS

Consumer-grade 3D printing displays potential as a fabrication method for postoperative cleft bilateral nasal supports and may support the surgically reconstructed internal contours. The results of this study suggest that such types of bioactive 3D prints may have potential applications in personalized drug-delivery systems and medical devices.

Three-Dimensional Printing Antimicrobial and Radiopaque Constructs

Three-dimensional (3D) printing holds tremendous potential as a tool for patient-specific devices. This proof-of- concept study demonstrated the feasibility, antimicrobial properties, and computed tomography(CT) imaging characteristics of iodine/polyvinyl alcohol (PVA) 3D meshes and stents. Under scanning electron microscopy, cross-linked PVA displays smoother and more compacted filament arrangements. X-ray and transaxial CT images of iodized PVA vascular stents show excellent visibility and significantly higher Hounsfield units of radiopacity than control prints. Three-dimensional PVA prints stabilized by glutaraldehyde cross-linking and loaded with iodine through sublimation significantly suppressed Escherichia coli and Staphylococcus aureus growth in human blood agar disk diffusion assays. It is suggested that PVA 3D printing with iodine represents an important new synthetic platform for generating a wide variety of antimicrobial and high-visibility devices.

Membrane topography of the renal phosphate carrier NaPi-2: limited proteolysis studies

The rat sodium/phosphate cotransporter NaPi-2 is a 70 kDa polypeptide (p70) for which eight transmembrane segments have been predicted. We have shown that p70 exists predominantly as p45 and p40 fragments which are linked by disulfide bonds. In this work, the p40 fragment, corresponding to the C-terminus of NaPi-2, was purified from renal brush-border membranes using non-reducing and then reducing column electrophoresis followed by enzymatic deglycosylation and SDS-PAGE. The N-terminal sequence obtained for this fragment, VEAIG, indicates that the formation of p45 and p40 arises from the cleavage of p70 between arginine-319 and valine-320. In order to determine the membrane topography of NaPi-2, brush-border membrane vesicles were digested with various proteases and the transporter-derived proteolytic peptides were subsequently identified by Western blotting using N- and C-terminal-directed antibodies. Our results lead us to propose an alternative topographical model in which p45 and p40 possess three transmembrane domains each and indicate that the processing site of p70 for the generation of p45 and p40 is localized in a large protein core facing the extracellular milieu. This localization of the cleavage site indicated that NaPi-2 could either be processed intracellularly by vesicular proteases or extracellularly by secretory proteases or by brush-border membrane ectoenzymes.

Immunodetection of a type III sodium-dependent phosphate cotransporter in tissues and OK cells

Polyclonal antibodies were raised in rabbits against a 14-amino acid portion of the gibbon ape leukemia virus human membrane receptor Glvr-1. This epitope also contained seven amino acids common to the receptor for the amphotropic murine retrovirus Ram-1. Antibody specificity and molecular size of Glvr-1/Ram-1-related proteins were assayed by Western blot. Using a standard Laemmli buffer system, under reducing conditions, a single band of approximately 85 kDa (designated p85) was immunodetected in membranes prepared from opossum kidney (OK) cells and in brain membranes from rat, rabbit and hamster. In mouse brain, p85 as well as a protein of 70-72 kDa were immunodetected. This protein was also present in several other mouse tissues. Limited proteolysis of p85 and the 70-72kDa-protein from mouse yielded similar peptide fragments, suggesting that both proteins are related. Fragments of the same molecular masses were also detected in OK cell membranes following proteolysis, showing that p85 in both models (mouse brain and OK cell) share a similar sequence. p85 is not N-glycosylated since an assay using endoglycosidase F/N-glycosidase F did not alter the electrophoretic mobility of p85. We also observed that regulation of phosphate transport by incubating OK cells without any phosphate or by PTH treatment occurs without any changes in the amount of p85. In conclusion, these data demonstrate for the first time a Western blot detection of a type III phosphate transporter using polyclonal antibodies. They also suggest that, conversely to type I and type II phosphate transporters which are localized in the kidney, this third type of transporter is ubiquitous and probably absorbs the readily available phosphate from interstitial fluid for normal cellular functions in many species and tissues, serving as a housekeeping Na+/Pi cotransport system. This is also the first report showing that p85 is not regulated in the same manner as type II phosphate transporters.

Involvement of disulphide bonds in the renal sodium/phosphate co-transporter NaPi-2

The rat renal brush border membrane sodium/phosphate co-transporter NaPi-2 was analysed in Western blots with polyclonal antibodies raised against its N-terminal and C-terminal segments. Under reducing conditions, proteins of 45-49 and 70-90 kDa (p45 and p70) were detected with N-terminal antibodies, and proteins of 40 and 70-90 kDa (p40 and p70) were detected with C-terminal antibodies. p40 and p45 apparently result from a post-translational cleavage of NaPi-2 but remain linked through one or more disulphide bonds. Glycosidase digestion showed that both polypeptides are glycosylated; the cleavage site could thus be located between Asn-298 and Asn-328, which have been shown to constitute the only two N-glycosylated residues in NaPi-2. In the absence of reducing agents, both N-terminal and C-terminal antibodies detected p70 and a protein of 180 kDa (p180), suggesting the presence of p70 dimers. Much higher concentrations of beta-mercaptoethanol were required to produce a given effect in intact membrane vesicles than in solubilized proteins, indicating that the affected disulphide bonds are not exposed at the surface of the co-transporter. Phosphate transport activity decreased with increasing concentrations of reducing agents [beta-mercaptoethanol, dithiothreitol and tris-(2-carboxyethyl)phosphine] and was linearly correlated with the amount of p180 detected. The target sizes estimated from the radiation-induced loss of intensity of p40, p70 and p180 were all approx. 190 kDa, suggesting that NaPi-2 exists as an oligomeric protein in which the subunits are sufficiently close to one another to allow substantial energy transfer between the monomers. When protein samples were pretreated with beta-mercaptoethanol [2.5% and 5% (v/v) to optimize the detection of p40 and p70] before irradiation, target sizes estimated from the radiation-induced loss of intensity of p40 and p70 were 74 and 92 kDa respectively, showing the presence of disulphide bridges in the molecular structure of NaPi-2.

Phosphate deprivation induces overexpression of two proteins related to the rat renal phosphate cotransporter NaPi-2

Polyclonal antibodies were raised in rabbits against the C-terminal portion of the rat renal brush-border membrane sodium/phosphate cotransporter NaPi-2. Antibody specificity and molecular sizes of proteins related to NaPi-2 were assayed by Western blot analysis. Proteins of 40 and 70-75 kDa (p40 and p70) were immunodetected in rat and mouse brush-border membranes and proteins of 72 and 82 kDa were detected in rabbit. The absence or presence of beta-EtSH in the samples before electrophoresis greatly influenced the immunodetection profile of the rat proteins. Since the 40 kDa protein (p40) can only be detected under reducing conditions, it probably originates from reduction of disulfide bonds in p70. Tryptic cleavage of p40 and p70 revealed identical protein fragments showing the close structural identity of those proteins. Both proteins were more abundant in the outer cortex portion of the rat kidney than in the juxtamedullary portion. Furthermore, rats fed a low-phosphate diet for 24 h showed a 20- and 14-fold increase in the amount of p40 and p70, respectively, compared to control rats, showing that the adaptation to P(i) deprivation by increasing renal phosphate reabsorption is not only the result of overproduction of p70, as previously shown, but is also due to the novel p40 which most probably derives from p70.

Successful use of cuffed central venous hemodialysis catheters inserted percutaneously

Although endogenous fistulae and grafts are preferred for permanent hemodialysis access, central venous catheters are often required for varying intervals when creating permanent access is not feasible. The prospective experience with 118 catheters in over a 3.5-yr period is reported; 93 (79%) were placed by percutaneous techniques, and 25 (21%) were placed by operative techniques. Seventy seven catheters (65%) were placed in the subclavian vein, 36 (31%) were placed in the internal jugular vein (usually right side), and 5 (4%) were placed in the femoral vein. Early postplacement complications were infrequent. Catheter function at last local follow-up ranged from several days to nearly 2 yr, averaging approximately 3 mo, even though many patients returned to their referring centers with a functioning catheter after only a short follow-up. Actuarial survival for percutaneously placed catheters was approximately 60% at 6 mo and 30% at 12 mo. Catheter failure occurred in 36% of cases, equally divided between malfunction (thrombosis refractory to fibrinolysis, extrusion, kinking, or related event) and infection with septicemia requiring removal. Such failure was not more frequent after percutaneous placement than after operative placement. Failure due to mechanical malfunction, but not that due to infection, tended to be less frequent among catheters placed in the internal jugular vein than among catheters placed in the subclavian vein. Finally, infection with septicemia involved 22% of all catheters and occurred at an average cumulated rate of approximately one infection per patient-year. Coagulase-positive staphylococcus was the most common organism isolated.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful use of indwelling cuffed femoral vein catheters in ambulatory hemodialysis patients

Three hemodialysis patients with multiple upper extremity vascular access complications and central vein stenosis were treated for as long as 3 months using an indwelling femoral vein catheter having a buried felt cuff in its subcutaneous tunnel. Four catheters were placed in these three patients. In one case, initial failure due to poor flow and clotting occurred using a straight catheter with its tunnel crossing the inguinal ligament and exiting caudally on the anterior thigh. Otherwise, each patient had successful placement of a 180-degree, curved catheter that exited the femoral vein in the usual fashion but had a subcutaneous tunnel and skin exit pointing cephalad in the inferior portion of the right lower quadrant. The three successful devices functioned immediately after placement, having acceptable outflow pressures and recirculation values. One of three catheters was removed 3 weeks after placement when persisting infection was thought to reside on the device. No other bleeding, thromboembolic, or infectious complications occurred in these patients. In conclusion, short-term indwelling femoral vein access may be feasible in ambulatory hemodialysis patients with previous access difficulties that complicate temporary dialysis treatment.