Circumferential Strain as a Marker of Vessel Reactivity in Patients with Intradialytic Hypotension.

Background and Objectives: Intradialytic hypotension (IDH) complicates 4 to 39.9% of hemodialysis (HD) sessions. Vessels' reactivity disturbances may be responsible for this complication. Two-dimensional speckle tracking is used to assess arterial circumferential strain (CS) as a marker of the effectiveness of the cardiovascular response to the reduction of circulating plasma. Materials and Methods: The common carotid artery (CCA) and common iliac artery (CIA) CSs were recorded using ultrasonography in 68 chronically dialyzed patients before and after one HD session. Results: In patients with IDH episodes (n = 26), the CCA-CS was significantly lower both before (6.28 ± 2.34 vs. 4.63 ± 1.74 p = 0.003) and after HD (5.00 (3.53-6.78) vs. 3.79 ± 1.47 p = 0.010) than it was in patients without this complication. No relationship was observed between CIA-CS and IDH. IDH patients had a significantly higher UF rate; however, they did not differ compared to complication-free patients either in anthropometric or laboratory parameters. Conclusions: Patients with IDH were characterized by lower pre- and post-HD circumferential strain of the common carotid artery. The lower CCA-CS showed that impaired vascular reactivity is one of the most important risk factors for this complication's occurrence.

The reaction of arteries to haemodialysis - can a change in the cross-sectional area be an important parameter in the assessment of the vessels' condition?

Purpose: The objectives of our study were to evaluate the changes in the cross-section area of carotid and femoral arteries caused by fluid loss during haemodialysis (HD) and to determine the direction and amount of these changes. Material and methods: Seventy-four HD patients (28 women and 46 men) were studied. We performed ultrasound exams of the distal common carotid and proximal femoral arteries in each patient before and after a HD session. Recorded exams were analysed using EchoPac software. Arterial cross-section area values were acquired for further analysis. Results: We found a statistically significant decrease in arterial systolic cross-section area values after HD sessions (carotid arteries area before HD equalled 0.6731 cm2 and 0.6333 cm2, p = 0.00001 after HD, femoral arteries area before HD equalled 0.8263 cm2 and 0.7635 cm2, p = 0.00001 after HD). The decrease of systolic carotid cross-section area correlated with the amount of fluid lost during HD sessions (correlation coefficient of 0.3122, p = 0.010) and the percentage of the body mass lost during HD (correlation coefficient of 0.3577, p = 0.003). No statistically significant changes were found in the femoral cross-section area. Conclusions: Our findings suggest that the arterial cross-section area may be used in the assessment of response to body fluid loss. We were able to measure changes due to fluid loss during the HD session. The carotid cross-section values decreased after the procedure and correlated with the amount of fluid lost during the HD session.

An Insight into the Stages of Ion Leakage during Red Blood Cell Storage.

Packed red blood cells (pRBCs), the most commonly transfused blood product, are exposed to environmental disruptions during storage in blood banks. In this study, temporal sequence of changes in the ion exchange in pRBCs was analyzed. Standard techniques commonly used in electrolyte measurements were implemented. The relationship between ion exchange and red blood cells (RBCs) morphology was assessed with use of atomic force microscopy with reference to morphological parameters. Variations observed in the Na+, K+, Cl-, H+, HCO3-, and lactate ions concentration show a complete picture of singly-charged ion changes in pRBCs during storage. Correlation between the rate of ion changes and blood group type, regarding the limitations of our research, suggested, that group 0 is the most sensitive to the time-dependent ionic changes. Additionally, the impact of irreversible changes in ion exchange on the RBCs membrane was observed in nanoscale. Results demonstrate that the level of ion leakage that leads to destructive alterations in biochemical and morphological properties of pRBCs depend on the storage timepoint.

Multimodal detection and analysis of a new type of advanced Heinz body-like aggregate (AHBA) and cytoskeleton deformation in human RBCs.

A new type of aggregate, formed in human red blood cells (RBCs) in response to glutaraldehyde treatment, was discovered and analyzed with the classical and advanced biomolecular imaging techniques. Advanced Heinz body-like aggregates (AHBA) formed in a single human RBC are characterized by a higher level of hemoglobin (Hb) degradation compared to typical Heinz bodies, which consist of hemichromes. The complete destruction of the porphyrin structure of Hb and the aggregation of the degraded proteins in the presence of Fe3+ ions are observed. The presence of such aggregated, highly degraded proteins inside RBCs, without cell membrane destruction, has been never reported before. For the first time the spatial differentiation of two kinds of protein mixtures inside a single RBC, with different phenylalanine (Phe) conformations, is visualized. The non-resonant Raman spectra of altered RBCs with AHBA are characterized by the presence of a strong band located at 1037 cm-1, which confirms that glutaraldehyde interacts strongly with Phe. The shape-shifting of RBCs from a biconcave disk to a spherical structure and sinking of AHBA to the bottom of the cell are observed. Results reveal that the presence of AHBA should be considered when fixing RBCs and indicate the analytical potential of Raman spectroscopy, atomic force microscopy and scanning near-field optical microscopy in AHBA detection and analysis.

Temporal sequence of the human RBCs' vesiculation observed in nano-scale with application of AFM and complementary techniques.

Based on the multimodal characterization of human red blood cells (RBCs), the link between the storage-related sequence of the nanoscale changes in RBC membranes in the relation to their biochemical profile as well as mechanical and functional properties was presented. On the background of the accumulation of RBCs waste products, programmed cell death and impaired rheological properties, progressive alterations in the RBC membranes including changes in their height and diameter as well as the in situ characterization of RBC-derived microparticles (RMPs) on the RBCs surface were presented. The advantage of atomic force microscopy (AFM) in RMPs visualization, even at the very early stage of vesiculation, was shown based on the results revealed by other reference techniques. The nanoscale characterization of RMPs was correlated with a decrease in cholesterol and triglycerides levels in the RBC membranes, proving the link between the lipids leakage from RBCs and the process of vesiculation.

An Analysis of Isolated and Intact RBC Membranes-A Comparison of a Semiquantitative Approach by Means of FTIR, Nano-FTIR, and Raman Spectroscopies.

This work presents the potential of vibrational spectroscopy, Vis and NIR Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) in reflection and transmission modes, and nano-FTIR microscopy to study the biochemical alterations in membranes of isolated and intact red blood cells (RBCs). The main goal was to propose the best spectroscopic method which enabled following biochemical alterations in the RBC membranes and then to translate this spectroscopic signature of degradation to in situ analysis of RBCs. Two models corresponding to two distinct cases of RBC membrane conditions were employed, and they were derived from healthy and young mice and mature mice with advanced atherosclerosis. It was shown that each technique provided essential information about biochemical alterations of the isolated membranes as well as membranes in the intact RBCs, which can be used in the development of a rapid and in situ analytical technology. Finally, we proposed that the combination of macro- and nanoprobing implemented in IR spectroscopy provided a wide chemical characterization of the RBC membranes, including alterations in lipid and protein fractions. This study also examined the effect of the sample preparation to determine destructive factors influencing a spectroscopic analysis of isolated membranes and intact RBCs derived from healthy and disease-affected mice.

Feasibility of two-dimensional speckle tracking in evaluation of arterial stiffness: Comparison with pulse wave velocity and conventional sonographic markers of atherosclerosis.

Objective Arterial stiffening is an early marker of atherosclerosis that has a prognostic value for cardiovascular morbidity and mortality. Although many markers of arterial hardening have been proposed, the search is on for newer, more user-friendly and reliable surrogates. One such potential candidate has emerged from cardiology, the speckle-tracking technique. The aim of this study was to evaluate the feasibility of the two-dimensional speckle tracking for the evaluation of arterial wall stiffness in comparison with standard stiffness parameters. Methods Carotid ultrasound and applanation tonometry were performed in 188 patients with no cardiovascular risk factors. The following parameters were then evaluated: the intima-media complex thickness, distensibility coefficient, ß-stiffness index, circumferential strain/strain rate, and pulse wave velocity and augmentation index. These variables were compared with each other and with patient age, and their reliability was assessed with Bland-Altman plots. Results Strain parameters derived from two-dimensional speckle tracking and intima-media complex thickness correlated better with age and pulse wave velocity than standard makers of arterial stiffness. Moreover, the reliability of these measurements was significantly higher than conventional surrogates. Conclusions Two-dimensional speckle tracing is a reliable method for the evaluation of arterial stiffness. Therefore, together with intima-media complex thickness measurement, it offers great potential in clinical practice as an early marker of atherosclerosis.

Right aortic arch analysis - Anatomical variant or serious vascular defect?

BACKGROUND: The right-sided aortic arch (RAA) is a rare congenital defect of the aorta. The aim of the study was to assess the occurrence of RAA in diagnoses performed by the University Radiology Department and analyze the frequency of concomitant vascular abnormalities. METHODS: The database of the Radiology Department was retrospectively analyzed between January 2008 and May 2016 with the keyword "right aortic arch". Twenty patients with this diagnosis were identified from a total of 11,690 CT examinations of the chest area, 19,623 CT examinations of brain-supplying vessels, and 1863 MRI examinations of the heart and aortic arch or brain-supplying arteries. The type of aortic arch, the occurrence of Kommerell's diverticulum and possible other vascular abnormalities, such as stenosis, kinking or occlusion, were then investigated. RESULTS: The analysis identified nine patients with type I and 11 patients with type II RAA. Eight of the 11 type II patients presented Kommerell's diverticulum. Concomitant vascular abnormalities were detected in four patients with type II RAA. In two cases, the right common carotid artery (RCCA) was narrowed by up to 80%, with steal phenomenon confirmed in one of them. In the second coincident right subclavian artery (RSA) stenosis was depicted. In two other cases, the aberrant left subclavian arteries (ALSA) were found to be narrowed at the level of origin by up to 70%. One patient was found with type B aortic dissection including ALSA and Kommerell's diverticulum. CONCLUSIONS: Our observations indicate that concomitant vascular abnormalities may occur more often than reported in literature. Patients diagnosed with type II RAA should be examined with Doppler ultrasonography to identify coincident vascular disorders, especially stenosis of the common carotid arteries or subclavian arteries.

Plasma Desphospho-Uncarboxylated Matrix Gla Protein as a Marker of Kidney Damage and Cardiovascular Risk in Advanced Stage of Chronic Kidney Disease.

BACKGROUND/AIMS: Desphospho-uncarboxylated matrix Gla protein (dp-ucMGP) is formed as a result of vitamin K insufficiency. The aim of this study was to investigate the association between plasma dp-ucMGP, kidney function and cardiovascular risk factors before and after 9-months substitution of vitamin K2 in non-dialysis patients with chronic kidney disease (CKD) stage 4 and 5. METHODS: 38 CKD patients were supplemented for 270±12 days with 90 µg vitamin K2 and 10 µg cholecalciferol or 10 µg cholecalciferol alone. At baseline and at follow-up circulating calcium, phosphate, lipids, hemoglobin, albumin and total protein, dp-ucMGP, osteoprotegerin, fetuin A, osteocalcin and fibroblast grown factor 23 (FGF-23) were assessed. Proteinuria was assessed in the first morning void. RESULTS: Baseline plasma dp-ucMGP was 1018.6±498.3 pmol/l and was significantly higher in patients at stage 5 CKD (1388.3 ±505.4 pmol/l) than at stage 4 (885.1±419.7 pmol/l), p=0.04. Vitamin K2 supplementation resulted in a decrease of dp-ucMGP level by 10.7%. Plasma dp-ucMGP was positively associated with proteinuria, serum creatinine, PTH and FGF-23; and inversely associated with glomerular filtration rate, serum hemoglobin and albumin. CONCLUSIONS: High dp-ucMGP level, reflecting a poor vitamin K status seems to be associated with kidney damage and may be also a marker of cardiovascular risk in CKD patients. Supplementation with vitamin K2 may improve the carboxylation status of MGP.

Neuroplasticity of sensory and sympathetic nerve fibers in a mouse model of a painful arthritic joint.

OBJECTIVE: Many forms of arthritis are accompanied by significant chronic joint pain. This study was undertaken to investigate whether there is significant sprouting of sensory and sympathetic nerve fibers in the painful arthritic knee joint and whether nerve growth factor (NGF) drives this pathologic reorganization. METHODS: A painful arthritic knee joint was produced by injection of Freund's complete adjuvant (CFA) into the knee joint of young adult mice. CFA-injected mice were then treated systemically with vehicle or anti-NGF antibody. Pain behaviors were assessed, and at 28 days following the initial CFA injection, the knee joints were processed for immunohistochemistry analysis using antibodies against calcitonin gene-related peptide (CGRP; sensory nerve fibers), neurofilament 200 kd (NF200; sensory nerve fibers), growth-associated protein 43 (GAP-43; sprouted nerve fibers), tyrosine hydroxylase (TH; sympathetic nerve fibers), CD31 (endothelial cells), or CD68 (monocyte/macrophages). RESULTS: In CFA-injected mice, there was a significant increase in the density of CD68+ macrophages, CD31+ blood vessels, and CGRP+, NF200+, GAP-43+, and TH+ nerve fibers in the synovium, as well as a significant increase in joint pain-related behaviors. None of these findings were observed in sham-injected mice. Administration of anti-NGF reduced these pain-related behaviors and the ectopic sprouting of nerve fibers, but had no significant effect on the increase in density of CD31+ blood vessels or CD68+ macrophages. CONCLUSION: These findings demonstrate that ectopic sprouting of sensory and sympathetic nerve fibers occurs in the painful arthritic joint and may be involved in the generation and maintenance of arthritic pain.

Sex-Specific Differences of Adenosine Triphosphate Levels in Red Blood Cells Isolated From ApoE/LDLR Double-Deficient Mice.

In this study for the first time, we investigated the correlation between sex-specific differences in adenosine triphosphate (ATP) levels in red blood cells (RBCs) and their mechanical, biochemical, and morphological alterations during the progression of atherosclerosis in ApoE/LDLR double-deficient (ApoE/LDLR-/-) mice. Our results indicate that both sex and age affect alterations in RBCs of both ApoE/LDLR-/- and C57BL/6J mice. When compared with male RBCs, female RBCs were characterized by lower basal ATP and mean corpuscular hemoglobin concentration (MCHC), higher hemoglobin concentration (HGB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), deformability, and phosphatidylserine (PS) exposure levels, regardless of age in both, ApoE/LDLR-/- and C57BL/6J mice. ApoE/LDLR-/- mice compared with age-matched controls showed lower basal ATP levels regardless of age and sex. Intracellular ATP level of RBCs was decreased solely in senescent female C57BL/6J mice, while it was elevated in males. Basal extracellular ATP levels were 400 times lower than corresponding intracellular level. In conclusion, basal ATP levels, RBC morphology, deformability, PS exposure levels alterations are sex-dependent in mice. Changes in basal ATP levels were correlated with PS exposure and trends of changes in MCV. Trends of changes of the most RBC parameters were similar in both sexes of ApoE/LDLR-/- mice compared with age-matched controls; however, their kinetics and levels vary greatly between different stages of disease progression.

Label-free testing strategy to evaluate packed red blood cell quality before transfusion to leukemia patients.

Patients worldwide require therapeutic transfusions of packed red blood cells (pRBCs), which is applied to the high-risk patients who need periodic transfusions due to leukemia, lymphoma, myeloma and other blood diseases or disorders. Contrary to the general hospital population where the transfusions are carried out mainly for healthy trauma patients, in case of high-risk patients the proper quality of pRBCs is crucial. This leads to an increased demand for efficient technology providing information on the pRBCs alterations deteriorating their quality. Here we present the design of an innovative, label-free, noninvasive, rapid Raman spectroscopy-based method for pRBCs quality evaluation, starting with the description of sample measurement and data analysis, through correlation of spectroscopic results with reference techniques' outcomes, and finishing with methodology verification and its application in clinical conditions. We have shown that Raman spectra collected from the pRBCs supernatant mixture with a proper chemometric analysis conducted for a minimum one ratio of integral intensities of the chosen Raman marker bands within the spectrum allow evaluation of the pRBC quality in a rapid, noninvasive, and free-label manner, without unsealing the pRBCs bag. Subsequently, spectroscopic data were compared with predefined reference values, either from pRBCs expiration or those defining the pRBCs quality, allowing to assess their utility for transfusion to patients with acute myeloid leukemia (AML) and lymphoblastic leukemia (ALL).

Serum osteoprotegerin is a predictor of progression of atherosclerosis and coronary calcification in hemodialysis patients.

BACKGROUND: The aim of this prospective cohort study was to evaluate the progression of coronary artery calcification (CAC), and atherosclerosis in hemodialysis (HD) patients and to relate them to novel biomarkers, i.e. serum osteoprotegerin (OPG) and fibroblast growth factor 23 (FGF-23). MATERIAL AND METHODS: Forty-seven HD patients were followed up for 30 months or until death. Intima media thickness (CCA-IMT), atherosclerotic plaques and CAC were assessed at baseline and after 30 months. Serum mineral parameters, lipids, OPG and plasma FGF-23 were also measured. RESULTS: At baseline, 70% HD patients presented detectable CAC. The patients without calcification at baseline remained calcification free at 30 months and presented lower serum OPG and FGF-23 than those with CAC. A 64.4% progression of CAC was observed in all patients with CAC at baseline. In parallel, a 13% increase in CCA-IMT was found. Both ΔCAC and ΔCCA-IMT correlated positively with baseline and follow-up serum OPG. The patients who died had significantly higher baseline CAC and serum OPG. CONCLUSION: The plasma level of OPG could serve as a surrogate marker of progression of atherosclerosis and calcification in patients with end-stage renal disease. Therefore, the serum OPG may be a candidate biomarker of cardiovascular complications and poor outcome among dialysis patients.

Peripheral arterial response during haemodialysis - is two-dimensional speckle-tracking a useful arterial reactivity assessment tool?

Aim: 2D speckle tracking is a method used in myocardial strain assessment. However, several studies have confirmed the suitability of its application in the assessment of arterial strain (a marker of arterial stiffness). The aims of our study were to evaluate whether 2D speckle tracking can assess the changes in carotid and femoral strain caused by fluid loss during haemodialysis, and to determine the direction and amount of these changes. Material and methods: We examined the distal common carotid and proximal femoral arteries in 74 haemodialysed patients (28 women and 46 men) before and after their haemodialysis sessions. EchoPac software was used to analyse the recorded ultrasound examinations. Circumferential strain values were acquired for further analysis. Results: We found a decrease in carotid circumferential strain values after haemodialysis sessions (5.916 ± 2.632% before haemodialysis and 4.909 ± 2.409% after haemodialysis, p = 0.000022). The amount of fluid lost during haemodialysis sessions correlated (correlation coefficient of 0.434, p = 0.000222) with the decrease of carotid circumferential strain. The correlation coefficients were slightly higher (0.445, p = 0.000146) when a ratio of fluid loss volume to the BMI was used. No statistically significant changes were found in femoral circumferential strain. Conclusions: Our findings suggest that arterial response to body fluid loss may be assessed by 2D speckle tracking. This method enabled us to measure carotid circumferential strain changes caused by fluid volume contraction during haemodialysis sessions. We found an important decrease in the carotid circumferential strain values after the procedure. The amount of this decrease correlated significantly with the decrease in the volume of fluid lost during the haemodialysis session.

Is contrast-enhanced ultrasonography (CEUS) useful in the assessment of obstructive uropathy-induced perfusion disorders?

Aim: The study aimed to evaluate the usefulness of contrast-enhanced ultrasonography in renal perfusion disorders caused by obstructive uropathy. Case description: We present a case of a patient with a horseshoe kidney, in which the urine outflow from the right part of the kidney was blocked due to the presence of a bladder tumour infiltrating the ureter. Perfusion disorders in both parts of the kidney, visible in computed tomography, were partially reflected in the ultrasound image. Conclusions: Doppler ultrasound and contrast-enhanced ultrasound may be useful for monitoring perfusion disorders in the course of obstructive uropathy, provided that appropriate methodology is developed to compare blood flow in both kidneys.

Age-related and atherosclerosis-related erythropathy in ApoE/LDLR-/- mice.

In this work we applied a multimodal approach to define the age- and atherosclerosis-related biochemical and functional alterations in red blood cells (RBCs) in ApoE/LDLR-/- mice. Our results revealed that age-related changes in RBCs, such as decreases in RBC deformability and mean height, were more pronounced in ApoE/LDLR-/- mice than in age-matched control mice (C57BL/6J). The decreases in phospholipid content and level of lipid unsaturation were accompanied by an increase in cholesterol esters and esterified lipids in RBC membranes in aged C57BL/6J mice. The age-related decrease in the phospholipid content was more pronounced in ApoE/LDLR-/- mice. In contrast, the increase in the total lipid content in RBC membranes occurred only in ApoE/LDLR-/- mice with advanced atherosclerosis. The age-related alterations also included a decrease in the ratio of turns to α-helices in the secondary structure of hemoglobin (Hb) inside intact RBCs. On the other hand, an increase in the ratio of unordered conformations to α-helices of Hb was observed only in ApoE/LDLR-/- mice and occurred already at the age of 5-weeks. This was related to hypercholesterolemia and resulted in an increased oxygen-carrying capacity. In conclusion, progressive mechanical and functional alterations of RBCs in aged ApoE/LDLR-/- mice were more pronounced than in age-matched C57BL/6J mice. Although, several biochemical changes in RBCs in aged ApoE/LDLR-/- mice recapitulated age-dependent changes observed in control mice, some biochemical features of RBC membranes attributed to hypercholesterolemia were distinct and could contribute to the accelerated deterioration of RBC function in ApoE/LDLR-/- mice.

Irreversible alterations in the hemoglobin structure affect oxygen binding in human packed red blood cells.

The ability of hemoglobin (Hb) to transport respiratory gases is directly linked to its quaternary structure properties and reversible changes between T (tense) and R (relax) state. In this study we demonstrated that packed red blood cells (pRBCs) storage resulted in a gradual increase in the irreversible changes in the secondary and quaternary structures of Hb, with subsequent impairment of the T↔R transition. Such alteration was associated with the presence of irreversibly settled in the relaxed form, quaternary structure of Hb, which we termed R'. On the secondary structure level, disordered protein organization involved formation of ß-sheets and a decrease in α-helices related to the aggregation process stabilized by strong intermolecular hydrogen bonding. Compensatory changes in RBCs metabolism launched to preserve reductive microenvironment were disclosed as an activation of nicotinamide adenine dinucleotide phosphate (NADPH) production and increased reduced to oxidized glutathione (GSH/GSSG) ratio. For the first time we showed the relationship between secondary structure changes and the occurrence of newly discovered R', which through an artificial increase in oxyhemoglobin level altered Hb ability to bind and release oxygen.

Relationship between renal resistive index and early target organ damage in patients with never-treated essential hypertension.

The aim of our study was to evaluate renal resistive index (RI) value in never treated hypertensive patients in relation to ambulatory blood pressure measurement (ABPM) values and early target organ damage. The study included 318 subjects: 223 patients with never treated essential hypertension (mean age 37.1 years) and 95 normotensive healthy subjects (mean age 37.9 years). ABPM, echocardiography and carotid and renal arteries duplex color Doppler examinations were performed. RI values in patients with never treated essential hypertension were no different from the normotensive control group (0.59 +/- 0.05 vs 0.59 +/- 0.05; NS). In the untreated patients RI correlated significantly with 24-h pulse pressure (r=0.234; p<0.01) and ambulatory arterial stiffness index (AASI) values (r=0.274; p<0.001), intima-media thickness (IMT) (r=0.249; p<0.001), E'/A' (rho= -0.279; p<0.001) and relative wall thickness (RWT; r=0.185; p<0.01). In the multivariate stepwise analysis, RI values correlated independently with carotid IMT (beta=0.272; p=0.020) and 24-h AASI values (beta=0.305; p=0.009). In normotensive healthy controls, significant independent correlation between RI and carotid IMT and 24-h AASI values were also found. Our study may indicate limited value of RI in differentiating patients with uncomplicated hypertension with healthy controls. Renal resistive values were independently correlated with carotid IMT and AASI. These may suggest that renal vascular resistance is related to two markers for cardiovascular events both in the hypertensive and normotensive subjects.

Arterial vessel reactivity in patients in the long term after kidney transplantation - preliminary study.

INTRODUCTION: The aim of this study was to evaluate the endothelial-dependent and -independent arterial vessels' reactivity in patients in the long term after kidney transplantation (KTx). MATERIAL AND METHODS: The study included 36 (15 females; 21 males) patients after KTx with good, stable graft function and 94 healthy individuals (51 males, 43 females). The endothelial-dependent dilatory capacity of the brachial artery was estimated by an ischemic test (flow-mediated dilation - FMD), and independent by nitroglycerin-mediated vasodilation (NMD). The results were shown for age-related groups and compared with age-related healthy people. RESULTS: KTx patients were mean 5.1 ±2.3 years after transplantation with the mean estimated glomerular filtration rate (eGFR) 50.3 ±17.1 ml/min/1.73 m2. The mean vessel diameter before tests was significantly larger in healthy people than in KTx patients. The FMD test showed vasodilation becoming weaker along with age in both groups, but in KTx patients this relationship was clearly enhanced. The NMD was delayed in relation to age, and in KTx patients was preserved, being only slightly weaker than in healthy people. CONCLUSIONS: Both endothelium-dependent and -independent arterial wall reactions decrease with age. The endothelial-dependent vascular response is more attenuated in KTx patients than the independent one. The endothelium-independent vasodilation in KTx patients is comparable with that in healthy people.