Association of vascular access type with inflammatory marker levels in maintenance hemodialysis patients

Frailty in patients on dialysis

Frailty is a condition that is frequently observed among patients undergoing dialysis. Frailty is characterized by a decline in both physiological state and cognitive state, leading to a combination of symptoms, such as weight loss, exhaustion, low physical activity level, weakness, and slow walking speed. Frail patients not only experience a poor quality of life, but also are at higher risk of hospitalization, infection, cardiovascular events, dialysis-associated complications, and death. Frailty occurs as a result of a combination and interaction of various medical issues in patients who are on dialysis. Unfortunately, frailty has no cure. To address frailty, a multifaceted approach is necessary, involving coordinated efforts from nephrologists, geriatricians, nurses, allied health practitioners, and family members. Strategies such as optimizing nutrition and chronic kidney disease-related complications, reducing polypharmacy by deprescription, personalizing dialysis prescription, and considering home-based or assisted dialysis may help slow the decline of physical function over time in subjects with frailty. This review discusses the underlying causes of frailty in patients on dialysis and examines the methods and difficulties involved in managing frailty among this group.

Relationship between Compound α-Ketoacid and Microinflammation in Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) refers to the presence of structural or functional abnormalities in the kidneys that affect health, lasting for more than 3 months. CKD is not only the direct cause of global incidence rate and mortality, but also an important risk factor for cardiovascular disease. Persistent microinflammatory state has been recognized as an important component of CKD, which can lead to renal fibrosis and loss of renal function, and plays a crucial role in the pathophysiology and progression of the disease. Simultaneously, compound α-Ketoacid can bind nitrogen-containing metabolites in the blood and accelerate their excretion from the body, thereby reducing the level of metabolic waste, alleviating gastrointestinal reactions in patients, and reducing the inflammatory response and oxidative stress state of the body. Compound α-Ketoacid contains amino acids required by CKD patients. In this review, we explore the relationship between compound α-Ketoacid and microinflammation in patients with CKD. The review indicated that compound α-Ketoacid can improve the microinflammatory state in CKD patients by improving the nutritional status of CKD patients, improving patient's acid-base balance disorder, regulating oxidative stress, improving gut microbiota, and regulating abnormal lipid metabolism.

Plasma Interleukin-6 Level Predicts the Risk of Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis

Systemic inflammation has been proposed as a relevant factor of vascular remodeling and dysfunction. We aimed to identify circulating inflammatory biomarkers that could predict future arteriovenous fistula (AVF) dysfunction in patients undergoing hemodialysis. A total of 282 hemodialysis patients were enrolled in this prospective multicenter cohort study. Plasma cytokine levels were measured at the time of data collection. The primary outcome was the occurrence of AVF stenosis and/or thrombosis requiring percutaneous transluminal angioplasty or surgery within the first year of enrollment. AVF dysfunction occurred in 38 (13.5%) patients during the study period. Plasma interleukin-6 (IL-6) levels were significantly higher in patients with AVF dysfunction than those without. Diabetes mellitus, low systolic blood pressure, and statin use were also associated with AVF dysfunction. The cumulative event rate of AVF dysfunction was the highest in IL-6 tertile 3 (p = 0.05), and patients in tertile 3 were independently associated with an increased risk of AVF dysfunction after multivariable adjustments (adjusted hazard ratio = 3.06, p = 0.015). In conclusion, circulating IL-6 levels are positively associated with the occurrence of incident AVF dysfunction in hemodialysis patients. Our data suggest that IL-6 may help clinicians identify those at high risk of impending AVF failure.

The change in Geriatric Nutritional Risk Index is associated with mortality in patients who start hemodialysis: Korean Renal Data Registry, 2016-2018

Malnutrition is common in patients undergoing hemodialysis (HD) and is associated with mortality. This study aimed to investigate the association between changes in nutrition status measured by the Geriatric Nutritional Risk Index (GNRI) and all-cause mortality in patients who started HD. A nationwide retrospective cohort study was conducted based on the Korean Renal Data System database. Patients who started HD from January 2016 to December 2018, and were eligible for GNRI and GNRI trend were included. GNRI trend was a longitudinal change of GNRI, assessed by random slope in a mixed-effect model. Positive and negative random slopes in each patient were assigned to positive and negative GNRI trends. A total of 2313 patients were included and median follow-up period was 3.1 (2.6-3.7) years. GNRI values decreased over time (estimate - 1.212, 95% confidence interval (CI) - 1.116-0.692) and positive GNRI trend was associated with survival benefit (hazard ratio 0.55, 95% CI 0.36-0.84) after multivariate adjustment. These findings show that serial GNRI assessment, besides GNRI, is a useful prognostic factor for mortality in patients who start HD.

Association of mean platelet volume/lymphocyte ratio with inflammation in non-dialysis patients with chronic kidney disease stages 1-4: A retrospective study

OBJECTIVE

The mean platelet volume/ratio (MPVLR) is recognized as a novel marker of inflammation. We evaluated whether the MPVLR is associated with inflammation in non-dialysis patients with chronic kidney disease (CKD) stages 1-4.

METHODS

A total of 402 non-dialysis patients with CKD stages 1-4 were included. The indicators of hematological, renal function (urea, serum creatinine [Scr], estimated glomerular filtration rate [eGFR], and urine albumin to creatinine ratio [ACR]) and the markers of inflammation (high-sensitivity C-reactive protein [hsCRP] and fibrinogen [FIB]) were recorded. The MPVLR values at different CKD stages were analyzed. Next, based on the absence (hsCRP level < 5 mg/L) and presence (hsCRP level > 5 mg/L) of inflammation, the patients were categorized, and the differences in indices between the two groups were observed. The patients were divided into two groups based on the median MPVLR value (6.39) at admission. The laboratory indices of patients with CKD were compared. Simultaneously, a correlation analysis was performed to identify the association between the MPVLR and each parameter. A binary logistic regression analysis was performed to test whether the MPVLR was associated independently with the presence of inflammation in non-dialysis patients with CKD. The receiver operating characteristic (ROC) curve was used to analyzed diagnostic performance of the MPVLR in evaluating the inflammation of non-dialysis patients with CKD stages 1-4.

RESULTS

The MPVLR was higher in patients with CKD stages 3-4 than in those with CKD stages 1 and 2. Significant differences in urea, Scr, eGFR, ACR, lymphocyte (LYM), red blood cell (RBC), hemoglobin (HGB), RBC distribution width (RDW-CV), MPVLR, and FIB values were observed between the groups with and without inflammation. The patients with a higher MPVLR had higher urea, Scr, ACR, WBC, neutrophils (NEU), RDW-CV, platelet distribution width (PDW), mean platelet volume (MPV), and hsCRP values and lower eGFR, LYM, RBC, HGB, and platelet (PLT) values. The MPVLR showed a positive correlation with age, urea, Scr, WBC, NEU, RDW-CV, PDW, MPV, and hsCRP values and a negative correlation with the eGFR, LYM, RBC, HGB, and PLT values. A logistic analysis revealed that the MPVLR was associated independently with the presence of inflammation in non-dialysis patients with CKD, after adjustment for the confounding factors (odds ratio = 1.020; P = 0.024). Furthermore, MPVLR exhibited a modest diagnostic performance for the assessment of inflammation in non-dialysis patients with CKD stages 1-4, with an area under the curve (AUC) of 0.706, and the sensitivity, specificity being 46.2% and 83.2%, respectively.

CONCLUSIONS

The MPVLR was associated independently with the presence of inflammation in non-dialysis patients with CKD and may be useful for monitoring inflammation.

High Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios Are Associated with a Higher Risk of Hemodialysis Vascular Access Failure

Our aim was to determine the predictive role of the preoperative neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in vascular access malfunctioning in patients who had undergone their first native arterio-venous fistula (AVF) for hemodialysis. Methods: This was a single-center retrospective observational study. All patients who underwent the procedure of the creation of a first native AVF for hemodialysis from January 2019 to December 2020 were considered eligible to be part of this study. Reinterventions for AVF malfunctioning were registered and the population was subdivided into two groups with respect to AVF malfunctioning. ROC curves were obtained to find the appropriate cut-off values for the NLR and PLR. A multivariate analysis was used to identify the independent predictors for an AVF malfunction. Kaplan−Meier curves were used to evaluate the AVF patency rates. A total of 178 patients were enrolled in the study, of them 70% (n = 121) were male. The mean age was 67.5 ± 12 years. Reinterventions for AVF malfunctioning were performed on 102 patients (57.3%). An NLR > 4.21 and a PLR > 208.8 was selected as the cut-off for AVF malfunctioning. The study population was divided into two groups depending on the NLR and PLR values of the individual. For the NLR < 4.21 group, the AVF patency rates were 90.7%, 85.3%, and 84% at the 3-, 6-, and 12-month follow-up, respectively, and 77.5%, 65.8%, and 39.3% at 3, 6, and 12 months for the NLR > 4.21 group, respectively (p < 0.0001). For the PLR < 208.8 group, the patency rates were 85.6%, 76.7%, and 67.7% at the 3-, 6-, and 12-month follow-up. For the PLR > 208.28 group, the patency rates were 80.8%, 71.2%, and 50.7% for the 3-, 6-, and 12-month follow-up, respectively (p = 0.014). The multivariate analysis highlighted that diabetes mellitus, the neutrophil count, the lymphocyte count, and the NLR were independent risk factors for an AVF failure. In our experience, the NLR and PLR are useful markers for the stratification of vascular access failure in hemodialysis patients. The inexpensive nature and ready availability of the values of these biomarkers are two points of strength for everyday clinical practice.

Influence of Tunneled Hemodialysis-Catheters on Inflammation and Mortality in Dialyzed Patients

Older age and comorbidities in hemodialysis patients determines the use of tunneled catheters as vascular access despite their reported clinical and mortality disadvantages. This prospective matched study analyzes the impact of permanent catheters on inflammation and mortality in hemodialysis patients; We studied 108 patients, 54 with AV-fistula (AVF) and 54 with indwelling hemodialysis catheters (HDC) matched by sex, age, diabetes and time under renal-replacement therapy comparing dialysis efficacy, inflammation and micro-inflammation parameters as well as mortality. Cox-regression analysis was applied to determine predictors of mortality, HDC patients presented higher C-reactive-protein (CRP) blood levels and percentage of pro-inflammatory lymphocytes CD14+/CD16+ with worse dialysis-efficacy parameters. Thirty-six-months mortality appeared higher in the HDC group although statistical significance was not reached. Age with a Hazard Ratio (HR) = 1.06, hypoalbuminemia (HR = 0.43), hypophosphatemia (HR = 0.75) and the increase in CD14+/CD16+ monocyte count (HR = 1.02) were predictors of mortality; elder patients dialyzing through HDC show increased inflammation parameters as compared with nAVF bearing patients, although they do not present a significant increase in mortality when matched by covariates. Increasing age and percentage of pro-inflammatory monocytes as well as decreased phosphate and serum-albumin were predictors of mortality and indicate the main conclusions or interpretations.

Understanding Development of Malnutrition in Hemodialysis Patients: A Narrative Review

Hemodialysis (HD) majorly represents the global treatment option for patients with chronic kidney disease stage 5, and, despite advances in dialysis technology, these patients face a high risk of morbidity and mortality from malnutrition. We aimed to provide a novel view that malnutrition susceptibility in the global HD community is either or both of iatrogenic and of non-iatrogenic origins. This categorization of malnutrition origin clearly describes the role of each factor in contributing to malnutrition. Low dialysis adequacy resulting in uremia and metabolic acidosis and dialysis membranes and techniques, which incur greater amino-acid losses, are identified modifiable iatrogenic factors of malnutrition. Dietary inadequacy as per suboptimal energy and protein intakes due to poor appetite status, low diet quality, high diet monotony index, and/or psychosocial and financial barriers are modifiable non-iatrogenic factors implicated in malnutrition in these patients. These factors should be included in a comprehensive nutritional assessment for malnutrition risk. Leveraging the point of origin of malnutrition in dialysis patients is crucial for healthcare practitioners to enable personalized patient care, as well as determine country-specific malnutrition treatment strategies.

Safety of radiotherapy for hemodialysis patients with cancer

BACKGROUND

The number of hemodialysis (HD) patients is increasing worldwide, and they are at a higher risk of cancer than the general population. Because HD patients are more likely to have inflammation, radiotherapy (RT)-induced adverse effects (AEs) are theoretically expected to be worse for HD patients. Since only a few reports have been published on this subject, we aimed to evaluate the tolerability of RT in HD patients.

METHODS

We retrospectively analyzed AEs related to RT for HD patients. Our study included patients from three institutions treated between January 2007 and July 2017. The patient eligibility criteria were (i) receipt of maintenance HD 2-3 times per week for end-stage renal disease prior to the start of RT and (ii) pathologically confirmed malignancies. The endpoints were acute and late non-hematologic AEs.

RESULTS

The study included 56 patients. The most common histology was head and neck cancer (23%), followed by lung cancer (14%) and prostate cancer (11%). The median radiation dose was 60 (range, 12-93.8) Gy at an equivalent dose in 2-Gy fractions (EQD2). The RT completion rate was 96%. Patients had a median follow-up period after RT of 9.1 (range 0.5-98.1) months. Grade 3 or worse acute and late AEs were noted in 6 (11%) and 3 (7%) patients, respectively. In the acute phase, 2 patients had grade 5 AEs, both of which were infections.

CONCLUSION

Our results suggest that RT for HD patients is clinically tolerable. However, some patients can experience severe infections related to treatment.

Survival and Prognostic Predictors of Primary Arteriovenous Fistula for Hemodialysis

Objectives: This study aims to evaluate the survival and prognostic predictors of arteriovenous fistulas (AVFs) among patients undergoing AVF creation. The significant predictors were incorporated into a prognostic model to determine its prognostic performance for five-year AVF survival.

Materials and Methods: Data on 290 patients who underwent first-time AVF creation and who had been followed up for at least 5 years or until AVF failure were reviewed. The Kaplan–Meier survival curves and Cox proportional hazards model were generated to determine the AVF survival and associated prognostic predictors. Significant predictors were used to derive a prognostic model.

Results: The mean age of the patients was 59.7±14.6 years, and the 5-year AVF survival rate was 34.5%. Three features were found to be independent prognostic factors for the five-year AVF survival: old age, diabetes mellitus, and prior central venous catheter placement. These three significant factors were integrated into a prognostic scoring model that ranged from zero to five points. According to this model, the patients whose scores were 0, 1, 2, 3 and 4 or more had five-year AVF survival rates of 60.0%, 45.3%, 36.6%, 15.0%, and 2.9%, respectively.

Conclusion: The five-year survival rate of AVFs was modest, and a prognostic model could excellently estimate the five-year AVF survival.

Maturation of arteriovenous fistulas in patients with and without preexisting hemodialysis catheters

Background

Central venous catheter (CVC) placement has been linked to systemic inflammation. This study was conducted to compare the successful maturation of arteriovenous fistulas (AVFs) and the preoperative white blood cell (WBC) profiles between patients with and without preexisting CVCs.

Materials and methods

A retrospective cohort study was conducted with 550 patients who underwent first-time AVF creation. Patients were divided into three groups according to preexisting CVCs and CVC types as follows: tunneled CVC (n = 23), nontunneled CVC (n = 223), and no CVC (n = 304). These three groups were compared in terms of AVF maturation and preoperative WBC profiles.

Results

The mean age of the patients was 61.1 ± 14.3 years. The AVF maturation rates of the tunneled CVC, nontunneled CVC and no CVC groups were 65.2%, 54.7% and 74.7%, respectively (p < 0.001). According to the uni- and multivariate analyses, only the nontunneled CVC group had a lower odds of AVF maturation compared to the no CVC group (adjusted odds ratio 0.43; 95% confidence interval 0.29–0.62). Patients with preexisting nontunneled CVC but not tunneled CVC also had significantly higher mean WBC and neutrophil counts but a lower percentage of lymphocytes than patients with no preexisting CVC.

Conclusion

Preexisting nontunneled CVC had a negative impact on the successful maturation of the newly created AVF. Patients in the nontunneled CVC group had the highest preoperative WBC and neutrophil counts but the lowest lymphocyte percentage compared to patients in the other two groups.

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Nontunneled CVC has a negative impact on the successful maturation of AVF.

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AVF maturation could be affected by duration of CVC placement.

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Preexisting nontunneled CVC is significantly related to high preoperative WBC count.

Antiplatelet agents maintain arteriovenous fistula and graft function in patients receiving hemodialysis: A nationwide case-control study

Background

In this study, we evaluated the effects of various medications on the patency of vascular access (VA) for hemodialysis.

Methods

We analyzed data from the Longitudinal Health Insurance Database of Taiwan. We adopted a case–control study design within a cohort of patients who had received regular hemodialysis between 2002 and 2012; 34,354 patients with first VA failure were identified, and the duration from VA creation date to the first VA failure date was calculated. We then classified these patients into two groups, namely arteriovenous fistula (AVF, n = 25,933) and arteriovenous graft (AVG, n = 8,421). Each group was further divided into two subgroups, namely short-term (<1 year) and long-term (≥1 year) patency.

Results

The risk factors for early VA failure were age ≥65 years, diabetes mellitus, hyperlipidemia, cerebral vascular disease, congestive heart failure, peripheral artery disease, and sepsis. Male sex, hypertension, cancer, and peptic ulcer were associated with early AVF failure. Antiplatelet therapy increased the AVF and AVG patency times with adjusted odds ratios of 0.748 (95% confidence interval [CI]: 0.703–0.796, p < 0.0001) and 0.810 (95% CI: 0.728–0.901, p = 0.0001), respectively. A significant decrease in the VA failure risk was observed with an increase in the cumulative defined daily dose of antiplatelet agents.

Conclusion

This nationwide study demonstrated that some risk factors were associated with early VA failure and that the use of antiplatelet agents prevented the loss of VA patency in a dose–response manner. Thus, antiplatelet drugs should be routinely administered to high-risk patients receiving dialysis.

Vascular Access Type and Clinical Outcomes among Elderly Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

The optimal type of initial permanent access for hemodialysis among the elderly is controversial. Duration of central venous catheter dependence, patient comorbidities, and life expectancy are important considerations in whether to place an arteriovenous fistula or graft. We used an observational study design to compare clinical outcomes in elderly patients who initiated hemodialysis with a central venous catheter and subsequently had an arteriovenous fistula or graft placed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified 9458 United States patients ages ≥67 years old who initiated hemodialysis from July 1, 2010 to June 30, 2011 with a central venous catheter and no secondary vascular access and then received an arteriovenous fistula (n=7433) or graft (n=2025) within 6 months. We evaluated key clinical outcomes during the 6 months after vascular access placement coincident with high rates of catheter use and used a matched propensity score analysis to examine patient survival.

RESULTS

Central venous catheter dependence was greater in every month during the 6-month period after arteriovenous fistula versus graft placement (P<0.001). However, rates of all-cause infection-related hospitalization (adjusted relative risk, 0.93; 95% confidence interval, 0.87 to 0.99; P=0.01) and bacteremia/septicemia-related hospitalization (adjusted relative risk, 0.90; 95% confidence interval, 0.82 to 0.98; P=0.02) were lower in the arteriovenous fistula versus graft group as was the adjusted risk of death (hazard ratio, 0.76; 95% confidence interval, 0.73 to 0.80; P<0.001).

CONCLUSIONS

Despite extended central venous catheter dependence, elderly patients initiating hemodialysis with a central venous catheter who underwent arteriovenous fistula placement within 6 months had fewer hospitalizations due to infections and a lower likelihood of death than those receiving an arteriovenous graft.

C-reactive protein variability is associated with vascular access outcome in hemodialysis patients

BACKGROUND

Hemodialysis (HD) vascular access failure is one of the most important causes of morbidity and contributes to the cost of dialysis care. There is paucity of data evaluating long-term monitoring of C-reactive protein (CRP) on outcome of HD vascular access.

METHODS

We conducted a retrospective study to investigate whether variability of serum CRP level was associated with vascular access failure rate over a 7-year period. A total of 318 HD patients were included. Their demographic data, co-morbidities and biochemical data were reviewed and collected. Serum high-sensitivity CRP (hs-CRP) level was measured every 6 months. Patients were divided into three groups according to their serial hs-CRP levels. Patients with their hs-CRP below 2 mg/L were defined as low group (n=65, 20.4%) and those with higher than 4 mg/L were defined as high (n=39, 12.3%). The rest were classified as fluctuated hs-CRP group (n=214, 67.3%). Treatment of vascular access failure includes angioplasty and access re-creation.

RESULTS

Their body mass index, indicators of dialysis adequacy and serum albumin and hs-CRP levels differed significantly among three groups. The annual vascular access failure rate was significantly higher in fluctuated hs-CRP group than in high hs-CRP group (0.41 vs 0.36, P=.037). Serum albumin was a significant associate of vascular access failure. Kaplan-Meier survival analysis indicated patients with high or fluctuated hs-CRP had shorter free interval of vascular access failure than low hs-CRP group.

CONCLUSIONS

HD patients with fluctuated hs-CRP levels were associated with increased vascular access failure.

Dialysis modality and nutritional status are associated with variability of inflammatory markers

BACKGROUND

Inflammation is a common feature in dialysis patients and is associated with cardiovascular complications and poor outcome. Measuring the variability of inflammatory markers may help in understanding underlying factors triggering inflammation. Whether the inflammatory pattern in hemodialysis (HD) and peritoneal dialysis (PD) patients differs has scarcely been studied. Here we explored factors associated with the magnitude and variability of inflammation markers in HD and PD patients.

METHODS

In two 3-month, prospective cohort studies comprising 228 prevalent HD and 80 prevalent PD patients, interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRP) were measured in blood samples drawn each month and every week, respectively. Information on comorbidity, protein-energy wasting (PEW) and medications was gathered at baseline, and information on symptoms potentially related to inflammation was gathered weekly. A mixed-effect model was used for multivariate analysis of factors linked to CRP and IL-6 variation.

RESULTS

IL-6 and CRP levels were higher and showed higher variability in HD versus PD patients [median IL-6 8.3 (interquartile range, IQR, 5.3-14.5) versus 6.7 (IQR 4.2-10.0) pg/mL, P < 0.001 and median CRP 6.1 (IQR 2.5-14.0) versus 5.4 (IQR 1.6-9.0) mg/L, P < 0.001). PEW predicted increased inflammation variability after correcting for age, sex, dialysis vintage, modality and comorbidity. Increased comorbidity predicted IL-6, but not CRP, variability.

CONCLUSIONS

Circulating concentrations as well as variability of IL-6 and CRP levels were higher in HD as compared with PD patients. In HD and PD patients, short-term variability of IL-6 and CRP levels associated strongly with PEW, while comorbidity was related to IL-6 but not to CRP variability.

Aortic Arch Calcification Predicts Patency Loss of Arteriovenous Fistula in End-Stage Renal Disease Patients

Aortic arch calcification (AAC) is recognized as an important cardiovascular risk factor in patients with end-stage renal disease (ESRD). The aim of the study was to evaluate the impact of AAC grade on patency rates of arteriovenous fistula (AVF) in this specific population. The data of 286 ESRD patients who had an initial AVF placed were reviewed. The extent of AAC identified on chest radiography was divided into four grades (0–3). The association between AAC grade, other clinical factors, and primary patency of AVF was then analyzed by Cox proportional hazard analysis. The multivariate analysis demonstrated that the presence of AAC grade 2 (hazard ratio (95% confidence interval): 1.80 (1.15–2.84); p = 0.011) and grade 3 (3.03 (1.88–4.91); p < 0.001), and higher level of intact-parathyroid hormone (p = 0.047) were associated with primary patency loss of AVF. In subgroup analysis, which included AVF created by a surgeon assisted with preoperative vascular mapping, only AAC grade 3 (2.41 (1.45–4.00); p = 0.001), and higher intact-parathyroid hormone (p = 0.025) level were correlated with AVF patency loss. In conclusion, higher AAC grade and intact-parathyroid hormone level predicted primary patency loss of AVF in an ESRD population.

Tracking and Therapeutic Value of Human Adipose Tissue-derived Mesenchymal Stem Cell Transplantation in Reducing Venous Neointimal Hyperplasia Associated with Arteriovenous Fistula

PURPOSE

To determine if adventitial transplantation of human adipose tissue-derived mesenchymal stem cells (MSCs) to the outflow vein of B6.Cg-Foxn1(nu)/J mice with arteriovenous fistula (AVF) at the time of creation would reduce monocyte chemoattractant protein-1 (Mcp-1) gene expression and venous neointimal hyperplasia. The second aim was to track transplanted zirconium 89 ((89)Zr)-labeled MSCs serially with positron emission tomography (PET) for 21 days.

MATERIALS AND METHODS

All animal experiments were performed according to protocols approved by the institutional animal care and use committee. Fifty B6.Cg-Foxn1(nu)/J mice were used to accomplish the study aims. Green fluorescent protein was used to stably label 2.5 × 10(5) MSCs, which were injected into the adventitia of the outflow vein at the time of AVF creation in the MSC group. Eleven mice died after AVF placement. Animals were sacrificed on day 7 after AVF placement for real-time polymerase chain reaction (n = 6 for MSC and control groups) and histomorphometric (n = 6 for MSC and control groups) analyses and on day 21 for histomorphometric analysis only (n = 6 for MSC and control groups). In a separate group of experiments (n = 3), animals with transplanted (89)Zr-labeled MSCs were serially imaged with PET for 3 weeks. Multiple comparisons were performed with two-way analysis of variance, followed by the Student t test with post hoc Bonferroni correction.

RESULTS

In vessels with transplanted MSCs compared with control vessels, there was a significant decrease in Mcp-1 gene expression (day 7: mean reduction, 62%; P = .029), with a significant increase in the mean lumen vessel area (day 7: mean increase, 176% [P = .013]; day 21: mean increase, 415% [P = .011]). Moreover, this was accompanied by a significant decrease in Ki-67 index (proliferation on day 7: mean reduction, 81% [P = .0003]; proliferation on day 21: mean reduction, 60%, [P = .016]). Prolonged retention of MSCs at the adventitia was evidenced by serial PET images of (89)Zr-labeled cells.

CONCLUSION

Adventitial transplantation of MSCs decreases Mcp-1 gene expression, accompanied by a reduction in venous neointimal hyperplasia.

Doppler ultrasound and calcification score: improving vascular access surveillance

AIM

Vascular access (VA) dysfunction limits hemodialysis delivery, which increases morbidity and mortality. The most com mon cause of VA failure is thrombosis, due to flow limiting stenosis resulting from neointimal hyperplasia. This occurs not only due to hemodynamic factors but also by systemic ones related to vascular atherosclerosis, inflammation and calcification, which has developed a simple vascular calcification score (SVCS) predictor of vascular calcification and arterial stiffness. The NKF-K/DOQ recommends several diagnostic procedures for VA surveillance. Blood access flow (Qa) has predictive power for the detection of stenosis. Our aim was to evaluate the role of systemic factors, especially SCVS, on Qa.

MATERIAL AND METHODS

Transversal study in 50 patients. Qa value was obtained with Blood Temperature Monitor and Doppler method. Pearson coefficient evaluated correlation between them. Clinical, lab and radiological variables were recorded and non-parametric tests evaluated how both Qa varied with them.

RESULTS

Pearson's corelation between DU-Qa and TD-Qa was 0.851 (p-value <0.001). DU-Qa varied significantly with age (p = 0.012), VA type (p = 0.021), SCVS (p = 0.030), intra-access arterial pressure (p = 0.015) and time on dialysis (p = 0.002). BTM-Qa varied significantly with diabetes status (p = 0.027), age (p = 0.017), first VA status (p = 0.036), intra-access arterial pressure (p = 0.028) and dialysis time (p = 0.001). Nevertheless, gender, hypertensive status and analitical parameters did not change the flow values.

CONCLUSION

Higher SVCS was associated only with lower DU-Qas, giving this method an advantage towards the indirect one. Additionally, a simple method like SVCS may be used to guide new surveillance recommendations accordingly to risk stratification.

CD4(+) lymphocytes improve venous blood flow in experimental arteriovenous fistulae

BACKGROUND

The role of immune cells in arteriovenous fistulae (AVF) maturation is poorly understood and has received, until quite recently, little attention. This study examines the function of T lymphocytes in AVF vascular remodeling.

METHODS

Experimental fistulae were created in athymic rnu nude rats lacking mature T lymphocytes and euthymic control animals by anastomosing the left superior epigastric vein to the nearby femoral artery. Blood flow rates, wall morphology, and histologic changes were assessed in AVF 21 days after creation. The effect of CD4(+) lymphocytes on AVF maturation in athymic animals was analyzed by adoptive transfer of cells after fistula creation.

RESULTS

The absence of T lymphocytes compromised blood flow in experimental fistulae. Histopathologic inspection of AVF from athymic rats revealed that T-cell immunodeficiency negatively affected venous vascular remodeling, as evidenced by a reduced lumen, a thick muscular layer, and a low number of inflammatory cells compared with control animals. Adoptive transfer of CD4(+) lymphocytes from euthymic rats into athymic animals after fistula creation improved blood flow and reduced intima-media thickness.

CONCLUSION

These results point at the protective role of CD4(+) lymphocytes in the remodeling of the AVF vascular wall.