The Effect of Everolimus Initiation and Calcineurin Inhibitor Elimination on Cardiac Allograft Vasculopathy in De Novo Recipients: One-Year Results of a Scandinavian Randomized Trial.

Early initiation of everolimus with calcineurin inhibitor therapy has been shown to reduce the progression of cardiac allograft vasculopathy (CAV) in de novo heart transplant recipients. The effect of de novo everolimus therapy and early total elimination of calcineurin inhibitor therapy has, however, not been investigated and is relevant given the morbidity and lack of efficacy of current protocols in preventing CAV. This 12-month multicenter Scandinavian trial randomized 115 de novo heart transplant recipients to everolimus with complete calcineurin inhibitor elimination 7-11 weeks after HTx or standard cyclosporine immunosuppression. Ninety-five (83%) patients had matched intravascular ultrasound examinations at baseline and 12 months. Mean (± SD) recipient age was 49.9 ± 13.1 years. The everolimus group (n = 47) demonstrated significantly reduced CAV progression as compared to the calcineurin inhibitor group (n = 48) (ΔMaximal Intimal Thickness 0.03 ± 0.06 and 0.08 ± 0.12 mm, ΔPercent Atheroma Volume 1.3 ± 2.3 and 4.2 ± 5.0%, ΔTotal Atheroma Volume 1.1 ± 19.2 mm(3) and 13.8 ± 28.0 mm(3) [all p-values ≤ 0.01]). Everolimus patients also had a significantly greater decline in levels of soluble tumor necrosis factor receptor-1 as compared to the calcineurin inhibitor group (p = 0.02). These preliminary results suggest that an everolimus-based CNI-free can potentially be considered in suitable de novo HTx recipients.

Effect of everolimus introduction on cardiac allograft vasculopathy--results of a randomized, multicenter trial.

BACKGROUND Everolimus reduces the progression of cardiac allograft vasculopathy (CAV) in de novo heart transplant (HTx) recipients, but the influence on established CAV is unknown. METHODS In this Nordic Certican Trial in Heart and lung Transplantation substudy, 111 maintenance HTx recipients (time post-HTx 5.8 ± 4.3 years) randomized to everolimus+reduced calcineurin inhibitor (CNI) or standard CNI had matching (intravascular ultrasound) examinations at baseline and 12 months allowing accurate assessment of CAV progression. RESULTS No significant difference in CAV progression was evident between the treatment groups (P = 0.30). When considering patients receiving concomitant azathioprine (AZA) therapy (n = 39), CAV progression was attenuated with everolimus versus standard CNI (Δmaximal intimal thickness 0.00 ± 0.04 and 0.04 ± 0.04 mm, Δpercent atheroma volume 0.2% ± 3.0% and 2.6% ± 2.5%, and Δtotal atheroma volume 0.25 ± 14.1 and 19.8 ± 20.4 mm(3), respectively [P < 0.05]). When considering patients receiving mycophenolate mofetil (MMF), accelerated CAV progression occurred with everolimus versus standard CNI (Δmaximal intimal thickness 0.06 ± 0.12 vs. 0.02 ± 0.06 mm and Δpercent atheroma volume 4.0% ± 6.3% vs. 1.4% ± 3.1%, respectively; P < 0.05). The levels of C-reactive protein and vascular cell adhesion molecule-1 declined significantly with AZA+everolimus, whereas MMF+everolimus patients demonstrated a significant increase in levels of C-reactive protein, vascular cell adhesion molecule-1, and von Willebrand factor. CONCLUSIONS Conversion to everolimus and reduced CNI does not influence CAV progression among maintenance HTx recipients. However, background immunosuppressive therapy is important as AZA+everolimus patients demonstrated attenuated CAV progression and a decline in inflammatory markers, whereas the opposite pattern was seen with everolimus+MMF. The different effect of everolimus when combined with AZA versus MMF could potentially reflect hitherto unknown interactions.

Cervical spinal locking plate in combination with cortical ring allograft for a one level fusion in dogs with cervical spondylotic myelopathy.

OBJECTIVE To evaluate use of a surgical technique commonly used in humans for treatment of cervical spondylotic myelopathy (CSM) in dogs. DESIGN Prospective case series. ANIMALS Dogs with CSM (n=10). METHODS Dogs weighing >30 kg that had CSM at 1 vertebral articulation were eligible for inclusion. Dogs had vertebral column distraction/fusion performed using a cortical ring allograft, cancellous autograft, and a spinal locking plate. Dogs were evaluated temporally by repeat neurological examinations and by client perception of postsurgical outcome, determined by telephone interview. RESULTS Nine dogs survived the immediate postoperative period. Seven of 8 dogs had moderate to complete improvement without recurrence (mean follow-up, 2.48 years). The most common postsurgical complications were screw loosening (n=4) and plate shifting (2), neither of which required surgical revision. One dog had pseudoarthrosis that may have negatively impacted outcome. CONCLUSION Treatment of single level CSM in dogs with ring allograft and a spinal locking plate system may lead to successful outcomes. The major problems encountered with included cost of the implants and adjusting the system designed for humans to fit the vertebral column of a dog. CLINICAL RELEVANCE For dogs with CSM at a single level, the use of a spinal locking plate in combination with a cortical ring allograft can be an effective surgical treatment. Costs of the implants as well as anatomic differences in dogs make this type of surgery less appealing.

Effect of Chronic Kidney Disease in Women Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents: A Patient-Level Pooled Analysis of Randomized Controlled Trials.

OBJECTIVES This study sought to evaluate: 1) the effect of impaired renal function on long-term clinical outcomes in women undergoing percutaneous coronary intervention (PCI) with drug-eluting stent (DES); and 2) the safety and efficacy of new-generation compared with early-generation DES in women with chronic kidney disease (CKD). BACKGROUND The prevalence and effect of CKD in women undergoing PCI with DES is unclear. METHODS We pooled patient-level data for women enrolled in 26 randomized trials. The study population was categorized by creatinine clearance (CrCl) <45 ml/min, 45 to 59 ml/min, and ≥60 ml/min. The primary endpoint was the 3-year rate of major adverse cardiovascular events (MACE). Participants for whom baseline creatinine was missing were excluded from the analysis. RESULTS Of 4,217 women included in the pooled cohort treated with DES and for whom serum creatinine was available, 603 (14%) had a CrCl <45 ml/min, 811 (19%) had a CrCl 45 to 59 ml/min, and 2,803 (66%) had a CrCl ≥60 ml/min. A significant stepwise gradient in risk for MACE was observed with worsening renal function (26.6% vs. 15.8% vs. 12.9%; p < 0.01). Following multivariable adjustment, CrCl <45 ml/min was independently associated with a higher risk of MACE (adjusted hazard ratio: 1.56; 95% confidence interval: 1.23 to 1.98) and all-cause mortality (adjusted hazard ratio: 2.67; 95% confidence interval: 1.85 to 3.85). Compared with older-generation DES, the use of newer-generation DES was associated with a reduction in the risk of cardiac death, myocardial infarction, or stent thrombosis in women with CKD. The effect of new-generation DES on outcomes was uniform, between women with or without CKD, without evidence of interaction. CONCLUSIONS Among women undergoing PCI with DES, CKD is a common comorbidity associated with a strong and independent risk for MACE that is durable over 3 years. The benefits of newer-generation DES are uniform in women with or without CKD.

Everolimus-Eluting Bioresorbable Vascular Scaffold System in the Treatment of Cardiac Allograft Vasculopathy: the CART (Cardiac Allograft Reparative Therapy) Prospective Multicenter Pilot Study.

Cardiac allograft vasculopathy (CAV) is a form of accelerated atherosclerosis, which represents the leading cause of late morbidity and mortality after heart transplantation. The recent bioresorbable vascular scaffold (BVS) technology represents a potential novel therapeutic tool, in the context of CAV, by allowing transient scaffolding and concomitant vessel healing. Eligible subjects will be treated by using the Absorb Everolimus-Eluting BVS (Abbott Vascular, Santa Clara, CA, USA), and evaluated at pre-determined time points, up to 3 years since the index procedure. Both clinical and imaging data will be collected in dedicated case report forms (CRF). All imaging data will be analyzed in an independent core laboratory. The primary aim of the study is to evaluate the angiographic performance at 1 year of second-generation Absorb BVS, in heart transplant recipients affected by CAV.

Use of Calcium Channel Blockers is Associated with Mortality in Patients with Chronic Kidney Disease.

BACKGROUND/AIMS The use of antihypertensive medicines has been shown to reduce proteinuria, morbidity, and mortality in patients with chronic kidney disease (CKD). A specific recommendation for a class of antihypertensive drugs is not available in this population, despite the pharmacodynamic differences. We have therefore analysed the association between antihypertensive medicines and survival of patients with chronic kidney disease. METHODS Out of 2687 consecutive patients undergoing kidney biopsy a cohort of 606 subjects with retrievable medical therapy was included into the analysis. Kidney function was assessed by glomerular filtration rate (GFR) estimation at the time point of kidney biopsy. Main outcome variable was death. RESULTS Overall 114 (18.7%) patients died. In univariate regression analysis the use of alpha-blockers and calcium channel antagonists, progression of disease, diabetes mellitus (DM) type 1 and 2, arterial hypertension, coronary heart disease, peripheral vascular disease, male sex and age were associated with mortality (all p<0.05). In a multivariate Cox regression model the use of calcium channel blockers (HR 1.89), age (HR 1.04), DM type 1 (HR 8.43) and DM type 2 (HR 2.17) and chronic obstructive pulmonary disease (HR 1.66) were associated with mortality (all p < 0.05). CONCLUSION The use of calcium channel blockers but not of other antihypertensive medicines is associated with mortality in primarily GN patients with CKD.

[Transition in kidney transplantation]

Transition from pediatric to adult care in renal transplantation has emerged as a critical step in the life of a young kidney recipient. During this phase, young patients are faced with the physiological and psychological changes associated with adolescence that can lead to non-compliance and potentially graft loss. To date, there is not a unique accepted model of transition, however it has been proved that the presence of a multidisciplinary team including specialists in adolescent management and in the transition from pediatric to adult transplant care is beneficial during this at-risk phase. The goal of this team is to ensure a progressive transition of the patients according to a precise plan and time line.

Diffusion tensor imaging of the human kidney: Does image registration permit scanning without respiratory triggering?

PURPOSE To investigate if image registration of diffusion tensor imaging (DTI) allows omitting respiratory triggering for both transplanted and native kidneys MATERIALS AND METHODS: Nine kidney transplant recipients and eight healthy volunteers underwent renal DTI on a 3T scanner with and without respiratory triggering. DTI images were registered using a multimodal nonrigid registration algorithm. Apparent diffusion coefficient (ADC), the contribution of perfusion (FP ), and the fractional anisotropy (FA) were determined. Relative root mean square errors (RMSE) of the fitting and the standard deviations of the derived parameters within the regions of interest (SDROI ) were evaluated as quality criteria. RESULTS Registration significantly reduced RMSE in all DTI-derived parameters of triggered and nontriggered measurements in cortex and medulla of both transplanted and native kidneys (P < 0.05 for all). In addition, SDROI values were lower with registration for all 16 parameters in transplanted kidneys (14 of 16 SDROI values were significantly reduced, P < 0.04) and for 15 of 16 parameters in native kidneys (9 of 16 SDROI values were significantly reduced, P < 0.05). Comparing triggered versus nontriggered DTI in transplanted kidneys revealed no significant difference for RMSE (P > 0.14) and for SDROI (P > 0.13) of all parameters. In contrast, in native kidneys relative RMSE from triggered scans were significantly lower than those from nontriggered scans (P < 0.02), while SDROI was slightly higher in triggered compared to nontriggered measurements in 15 out of 16 comparisons (significantly for two, P < 0.05). CONCLUSION Registration improves the quality of DTI in native and transplanted kidneys. Diffusion parameters in renal allografts can be measured without respiratory triggering. In native kidneys, respiratory triggering appears advantageous. J. Magn. Reson. Imaging 2016.

Racial Disparities in Access to and Outcomes of Kidney Transplantation in Children, Adolescents, and Young Adults: Results From the ESPN/ERA-EDTA (European Society of Pediatric Nephrology/European Renal Association-European Dialysis and Transplant Association) Registry.

BACKGROUND Racial disparities in kidney transplantation in children have been found in the United States, but have not been studied before in Europe. STUDY DESIGN Cohort study. SETTING & PARTICIPANTS Data were derived from the ESPN/ERA-EDTA Registry, an international pediatric renal registry collecting data from 36 European countries. This analysis included 1,134 young patients (aged ≤19 years) from 8 medium- to high-income countries who initiated renal replacement therapy (RRT) in 2006 to 2012. FACTOR Racial background. OUTCOMES & MEASUREMENTS Differences between racial groups in access to kidney transplantation, transplant survival, and overall survival on RRT were examined using Cox regression analysis while adjusting for age at RRT initiation, sex, and country of residence. RESULTS 868 (76.5%) patients were white; 59 (5.2%), black; 116 (10.2%), Asian; and 91 (8.0%), from other racial groups. After a median follow-up of 2.8 (range, 0.1-3.0) years, we found that black (HR, 0.49; 95% CI, 0.34-0.72) and Asian (HR, 0.54; 95% CI, 0.41-0.71) patients were less likely to receive a kidney transplant than white patients. These disparities persisted after adjustment for primary renal disease. Transplant survival rates were similar across racial groups. Asian patients had higher overall mortality risk on RRT compared with white patients (HR, 2.50; 95% CI, 1.14-5.49). Adjustment for primary kidney disease reduced the effect of Asian background, suggesting that part of the association may be explained by differences in the underlying kidney disease between racial groups. LIMITATIONS No data for socioeconomic status, blood group, and HLA profile. CONCLUSIONS We believe this is the first study examining racial differences in access to and outcomes of kidney transplantation in a large European population. We found important differences with less favorable outcomes for black and Asian patients. Further research is required to address the barriers to optimal treatment among racial minority groups.

Prevalence and risk factors for polyomavirus reactivation in solid-organ transplantation

Background. Polyomavirus reactivation is common in solid-organ transplant recipients who are given immunosuppressive medications as standard treatment of care. Previous studies have shown that polyomavirus infection can lead to allograft failure in as many as 45% of the affected patients. Hypothesis. Ubiquitous polyomaviruses when reactivated by post-transplant immunosuppressive medications may lead to impaired renal function and possibly lower survival prospects. Study Overview. Secondary analysis of data was conducted on a prospective longitudinal study of subjects who were at least 18 years of age and were recipients of liver and/or kidney transplant at Mayo Clinic Scottsdale, Arizona. Methods. DNA extractions of blinded urine and blood specimens of transplant patients collected at Mayo Clinic during routine transplant patient visits were performed at Baylor College of Medicine using Qiagen kits. Virologic assays included testing DNA samples for specific polyomavirus sequences using QPCR technology. De-identified demographic and clinical patient data were merged with laboratory data and statistical analysis was performed using Stata10. Results. 76 patients enrolled in the study were followed for 3.9 years post transplantation. The prevalence of BK virus and JC virus urinary excretion was 30% and 28%. Significant association was observed between JC virus excretion and kidney as the transplanted organ (P = 0.039, Pearson Chi-square test). The median urinary JCV viral loads were two logs higher than those of BKV. Patients that excreted both BKV and JCV appeared to have the worst renal function with a mean creatinine clearance value of 71.6 millimeters per minute. A survival disadvantage was observed for dual shedders of BKV and JCV, log-rank statistics, p = 0.09; 2/5 dual-shedders expired during the study period. Liver transplant and male sex were determined to be potential risk factors for JC virus activation in renal and liver transplant recipients. All patients tested negative for SV40 and no association was observed between polyomavirus excretion and type of immunosuppressive medication (tacrolimus, mycophenolate mofetil, cyclosporine and sirolimus). Conclusions. Polyomavirus reactivation was common after solid-organ transplantation and may be associated with impaired renal function. Male sex and JCV infection may be potential risk factors for viral reactivation; findings should be confirmed in larger studies.^

A case-control study of medication-associated acute kidney injuries in hospitalized pediatric patients

Acute kidney Injury (AKI) in hospitalized pediatric patients can be a significant event that can result in increased patient morbidity and mortality. The incidence of medication associated AKI is increasing in the pediatric population. Currently, there are no data to quantify the risks of developing AKI for various potentially nephrotoxic medications. The primary objective of this study was to determine the odds of nephrotoxic medication exposure in hospitalized pediatric patients with AKI as defined by the pediatric modified pRIFLE criteria. A retrospective case-control study was performed with patients that developed AKI, as defined by the pediatric pRIFLE criteria, as cases, and patients without AKI as controls that were matched by age category, gender, and disease state. Patients between 1 day and 18 years of age, admitted to a non-intensive care unit at Texas Children's Hospital for at least 3 days, and had at least 2 serum creatinine values drawn were included. Patient data was analyzed with Student's t test, Mann-Whitney U test, Chi square analysis, ANOVA, and conditional logistic regression. ^ Out of 1,660 patients identified for inclusion, 561 (33.8%) patients had AKI, and 357 cases were matched with 357 controls to become pairs. Of the cases, 441 were category 'R', 117 category 'I', 3 patients were category 'F', and no patient died. Cases with AKI were significantly younger than controls (p < 0.05). Significantly longer hospital length of stays, increased hospital costs, and exposure to more nephrotoxic medications for a longer period of time were characteristics of patients with AKI compared to patient without AKI. Patients with AKI had greater odds of exposure to one or more nephrotoxic medication than patients without AKI (OR 1.3, 95% CI 1.1–1.4, p < 0.05). Percent changes in estimated creatinine clearance (eCCl) from baseline were greatest with increased number of nephrotoxic medication exposures. ^ Exposure to potentially nephrotoxic medications may place pediatric patients at greater risk of acute kidney injury. Multiple nephrotoxic medication exposure may confer a greater risk of development of acute kidney injury, and result in increased hospital costs and patient morbidity. Due to the high percentage of patients that were exposed to potentially nephrotoxic medications, monitoring and medication selection strategies may need to be altered to prevent or minimize risk.^

Analysis of Wnt/beta-catenin signaling in kidney tubulogenesis

The β-catenin/Lef/Tcf-mediated Wnt pathway is central to the developmental of all animals, stem cell renewal, and cancer progression. Prior studies in frogs and mice have indicated that the ligand Wnt-4 is essential for the mesenchyme to epithelial transition that generates tubules in the context of kidney organogenesis. More recently, Wnt-9b in mice, was likewise found to be required. Yet despite the importance of Wnt signals in renal development, the corresponding Frizzled receptor(s) and downstream signaling mechanim(s) are unclear. My work addresses these knowledge gaps using in vitro (Madin-Darby Canine Kidney cells) and in vivo (Xenopus laevis and zebrafish pronephros) tubulogenic kidney model systems. Employing established reporter constructs of Wnt/β-catenin pathway activity, I have determined that MDCK cells are highly responsive to Wnt-4, -1, and -3A, but not to Wnt-5A and control conditions. I have confirmed that Wnt-4's canonical signaling activity in MDCK cells is mediated by downstream effectors of the Wnt/β-catenin pathway using β-Engrailed and dnTCF-4, constructs that suppress this pathway. I have further found that MDCK cells express the Frizzled-6 receptor, and that Wnt-4 forms a biochemical complex with Frizzled-6, yet does not appear to transduce Wnt-4's canonical signal. Additionally, I demonstrate that standard Hepatocyte Growth Factor (HGF)-mediated (non-physiologic) induction of MDCK tubulogenesis in collagen matrices is not altered by activation or suppression of β-catenin signaling activity; however, β-catenin signaling maintains cell survival in this in vitro system. Using a Wnt/β-catenin signaling reporter in Xenopus laevis, I detect β-catenin signaling activity in the early pronephric epithelial kidney tubules. By inhibiting the Wnt/β-catenin signaling pathway in both zebrafish and Xenopus , a significant loss of kidney tubulogenesis is observed with little or no effect on adjoining axis or somite development. This inhibition also leads to the appearance of severe edema that phenocopies embryos depleted for Wnt-4. Tubulogenic loss does not appear to be caused by increased cell death in the Xenopus pronephric field, but rather by lessened expression of tubule epithelium genes associated with cellular differentiation. Together, my results show that Wnt/β-catenin signaling is required for renal tubule development and that Wnt-4 is a strong candidate for activating this pathway. ^

Effects of overweight and obesity on economic outcomes among U.S. adults with kidney disease

Background. Kidney disease is a growing public health phenomenon in the U.S. and in the world. Downstream interventions, dialysis and renal transplants covered by Medicare's renal disease entitlement policy in those who are 65 years and over have been expensive treatments that have been not foolproof. The shortage of kidney donors in the U.S. has grown in the last two decades. Therefore study of upstream events in kidney disease development and progression is justified to prevent the rising prevalence of kidney disease. Previous studies have documented the biological route by which obesity can progress and accelerate kidney disease, but health services literature on quantifying the effects of overweight and obesity on economic outcomes in the context of renal disease were lacking. Objectives . The specific aims of this study were (1) to determine the likelihood of overweight and obesity in renal disease and in three specific adult renal disease sub-populations, hypertensive, diabetic and both hypertensive and diabetic (2) to determine the incremental health service use and spending in overweight and obese renal disease populations and (3) to determine who financed the cost of healthcare for renal disease in overweight and obese adult populations less than 65 years of age. Methods. This study was a retrospective cross-sectional study of renal disease cases pooled for years 2002 to 2009 from the Medical Expenditure Panel Survey. The likelihood of overweight and obesity was estimated using chi-square test. Negative binomial regression and generalized gamma model with log link were used to estimate healthcare utilization and healthcare expenditures for six health event categories. Payments by self/family, public and private insurance were described for overweight and obese kidney disease sub-populations. Results. The likelihood of overweight and obesity was 0.29 and 0.46 among renal disease and obesity was common in hypertensive and diabetic renal disease population. Among obese renal disease population, negative binomial regression estimates of healthcare utilization per person per year as compared to normal weight renal disease persons were significant for office-based provider visits and agency home health visits respectively (p=0.001; p=0.005). Among overweight kidney disease population health service use was significant for inpatient hospital discharges (p=0.027). Over years 2002 to 2009, overweight and obese renal disease sub-populations had 53% and 63% higher inpatient facility and doctor expenditures as compared to normal weight renal disease population and these result were statistically significant (p=0.007; p=0.026). Overweigh renal disease population had significant total expenses per person per year for office-based and outpatient associated care. Overweight and obese renal disease persons paid less from out-of-pocket overall compared to normal weight renal disease population. Medicare and Medicaid had the highest mean annual payments for obese renal disease persons, while mean annual payments per year were highest for private insurance among normal weight renal disease population. Conclusion. Overweight and obesity were common in those with acute and chronic kidney disease and resulted in higher healthcare spending and increased utilization of office-based providers, hospital inpatient department and agency home healthcare. Healthcare for overweight and obese renal disease persons younger than 65 years of age was financed more by private and public insurance and less by out of pocket payments. With the increasing epidemic of obesity in the U.S. and the aging of the baby boomer population, the findings of the present study have implications for public health and for greater dissemination of healthcare resources to prevent, manage and delay the onset of overweight and obesity that can progress and accelerate the course of the kidney disease.^

(Table 1) Retinol (vitamin A) and alpha-tocopherol (vitamin E) concentration in polar bear (Ursus maritimus) kidney

Vitamins A and E content of inner organs, among these the kidneys, are increasingly being used as an indicator of adverse effects caused to the organism by e.g. environmental contaminants. In general, only a renal sub sample is used for analyses, and it is thus essential to know which part of the organ to sample in order to get a representative value for this important biomarker. The aim here was to assess the distribution of vitamins A (retinol) and E (alpha-tocopherol) within the polar bear multireniculate kidney (i.e. polar vs. medial position) and also within the cortex vs. medulla of each separate renculi. The results showed no significant difference between the medial and polar renculi with regards to either retinol (p = 0.44) or alpha-tocopherol (p = 0.75). There were, however, significant differences between cortex and medulla for both vitamins (retinol, p = 0.0003; alpha-tocopherol, p<0.0001). The kidney cortex contained higher values of both vitamins than the medulla; on average 29% more retinol and 57% more alpha-tocopherol. Mean concentrations in the medulla was 2.7 mg/kg for retinol and 116 mg/kg for alpha-tocopherol, and in the cortex 3.5 mg/kg for retinol and 182 mg/kg for alpha-tocopherol. These results clearly indicate that one should take precautions when analyzing retinol and alpha-tocopherol in polar bear kidneys. Prior to analysis, the renculi should be separated into medulla and cortex. The results indicated no significant differences between renculi from different parts of the kidney.

Raft association of SNAP receptors acting in apical trafficking in Madin–Darby canine kidney cells

We have investigated the relationships between the apical sorting mechanism using lipid rafts and the soluble N-ethyl maleimide-sensitive factor attachment protein receptor (SNARE) machinery, which is involved in membrane docking and fusion. We first confirmed that anti-alpha-SNAP antibodies inhibit the apical pathway in Madin– Darby canine kidney (MDCK) cells; in addition, we report that a recombinant SNAP protein stimulates the apical transport whereas a SNAP mutant inhibits this transport step. Based on t-SNARE overexpression experiments and the effect of botulinum neurotoxin E, syntaxin 3 and SNAP-23 have been implicated in apical membrane trafficking. Here, we show in permeabilized MDCK cells that antisyntaxin 3 and anti-SNAP-23 antibodies lower surface delivery of an apical reporter protein. Moreover, using a similar approach, we show that tetanus toxin-insensitive, vesicle-associated membrane protein (TI-VAMP; also called VAMP7), a recently described apical v-SNARE, is involved. Furthermore, we show the presence of syntaxin 3 and TI-VAMP in isolated apical carriers. Polarized apical sorting has been postulated to be mediated by the clustering of apical proteins into dynamic sphingolipid-cholesterol rafts. We provide evidence that syntaxin 3 and TI-VAMP are raft-associated. These data support a raft-based mechanism for the sorting of not only apically destined cargo but also of SNAREs having functions in apical membrane-docking and fusion events.