Abstract
Background and Aims
Human kidneys have a role in water homeostasis, acid-base control, reabsorption of compounds, and secretion of xenobiotics and endogenous metabolites, exposing them to ...substances that could cause harm. This results in an alarming number of acute kidney injuries (AKI) worldwide, estimated at 13%. Furthermore, one-quarter of hospitalised cases are due to drug-induced AKI 1. Current methods for nephrotoxicity assays are based on animal testing and/or the use of simple human cell lines. Meta-analyses show that we can correctly predict human drug responses in only 10–50% 2. Our work aimed to develop a novel and optimised protocol for isolating proximal tubular epithelial cells (PTEC) from human kidney biopsy to aid future research regarding AKI and nephrotoxicity studies.
Method
Isolation and cultivation of primary human adult PTEC obtained with biopsy during the regular diagnostic procedure was performed. We used a protocol consisting of micro-dissection of a tissue sample to get ∼1 mm3 fragments, enzymatic dissociation with 0.2% collagenase type 1, and use of selective culture media (Advanced DMEM/F12 with added insulin, transferrin, and selenite (all three together termed ITS), epidermal growth factor (EGF), and hydrocortisone). Light microscopy was used for morphologic characterisation. Some cells were cultured on Transwell inserts, and the transepithelial electric resistance (TEER) was measured in mature cells that formed a confluent culture. For phenotypic characterisation, several markers characteristic of PTEC were chosen 3, and immunocytochemical staining was performed using a fluorescent microscope to evaluate the PTEC phenotype.
Results
Following the described protocol resulted in isolating cells that formed first colonies after 24 h. Using light microscopy, the cells exhibited a cobblestone appearance, reached confluence after eight days, and showed dome (hemicysts) formation after 13 days. TEER reached 169 Ω/cm2 after 14 days. The isolated cells were marked positive using immunocytochemistry for sodium-glucose cotransporter 2 (SGLT2), multidrug-resistant protein 4 (MRP4), organic anionic transporter 1 and 3 (OAT1 and OAT3), organic cationic transporter 2 (OCT2), p-glycoprotein (p-gp), multidrug and toxin extrusion protein 1 (MATE1), and N-cadherin.
Conclusion
In this study, we developed a protocol for isolating and cultivating primary human PTEC from biopsy samples. To the best of our knowledge, we have performed the most extensive systematic characterisation following the isolation of PTEC from kidney biopsy reported to date.
Abstract
Background and Aims
Serum cystatin C (cysC) is produced by all nucleated cells at a constant rate, is filtered freely by the glomerulus and metabolized after tubular reabsorption. It is ...influenced less by age, gender and muscle mass compared to serum creatinine. These properties make it an important marker in detecting renal impairment. Arterial stiffness is a hallmark of atherosclerosis and is connected to cardiovascular events and mortality. In patients with chronic kidney disease (CKD), cysC correlates with increased arterial stiffness, but less is known about the association between cysC and arterial stiffness in non-CKD patients.
Method
The study was performed at the University Medical Centre Maribor between October 1st 2018 and January 1st 2020. Basic demographic and laboratory data were recorded. To estimate glomerular filtration rate (eGFR), Chronic Kidney Disease Epidemiology (CKD-EPI) equation was used. Patients with previously diagnosed CKD and/or eGFR ≤ 60 ml/min/1.73m2 at the time of admission, known malignancy, thyroid disease and/or on steroid therapy were not enrolled in the study. Arterial stiffness was measured with applanation tonometry (Sphygmocor®, Australia), carotid-femoral pulse wave velocity (cfPWV) was used as the gold standard of central arterial stiffness and subendocardial viability ratio (SEVR) was used as the marker of myocardial perfusion. SPSS® version 22 was used for statistical analysis.
Results
111 patients (65.8% male, average age 64.3±9.4 years) were included in our study. Most common comorbidities were arterial hypertension (n=86, 77.5%), hyperlipidaemia (n=64, 57.7%) and diabetes mellitus (n=22, 19.8%). Mean creatinine value was 77.7±13.8 μmol/L (range 49-108 μmol/L), mean eGFR was 81.3±9.4 ml/min/1.73m2 (range 62-90 ml/min/1.73m2) and mean value of cysC was 0.94±0.18 mg/L (range 0.67-1.63 mg/L). Mean SEVR value was 165.7±36.1% (range 92-299%) and mean cfPWV value was 10.1±2.4 m/s (range 6.2-16.8 m/s). Significant correlation was found between cysC and SEVR (r=-0.316, p<0.001) and between cysC and cfPWV (r=0.472, p<0.001). Multiple regression analysis of arterial stiffness indices and cysC, age, gender, diabetes mellitus, arterial hypertension, eGFR and hyperlipidemia, showed statistically significant association between cysC and cfPWV (ß=0.220, p=0.038) and cysC and SEVR (ß=-0.278, p=0.017).
Conclusion
Serum cysC is independently associated with increased arterial stiffness, reduced myocardial perfusion and increased cardiovascular risk in non-CKD patients.
Atherosclerosis is a leading cause of morbidity and mortality in hemodialysis (HD) patients. Low (<0.90) and high (>1.40) ankle‐brachial index (ABI) is known as a non‐invasive diagnostic marker for ...generalized atherosclerosis associated with higher cardiovascular (CV) mortality in the general population. Less is known about associations between ABI and CV mortality in HD patients. The aim of our study was to determine the impact of the ABI on CV mortality in nondiabetic HD patients. Fifty‐two nondiabetic HD patients (mean age 59 years, range 22 – 76 years) were enrolled in our study. Twenty‐three (44%) were women and 29 (56%) men. The ABI was determined using an automated, non‐invasive, waveform analysis device. All patients were divided according to the ABI into three groups: low ABI (<0.9), normal ABI (0.9–1.4) and high ABI (>1.4). The presence of arterial hypertension and smoking was established. Serum cholesterol (HDL and LDL) and triglycerides were measured by routine laboratory methods. Survival rates were analyzed using Kaplan–Meier survival curves. The Cox regression model was used to assess the influence of the ABI on CV outcomes. The model was adjusted for age, arterial hypertension, smoking, cholesterol and triglycerides. Mean ABI value was 1.2 ± 0.3 (range 0.2–2.2). Patients were observed from the date of the ABI measurement until their death or maximally up to 1620 days. Kaplan–Meier survival analysis showed that the risk for CV death was higher for HD patients with low and high ABI compared to normal ABI (log rank test: P < 0.006; P < 0.0001). In the adjusted Cox multivariable regression model low and high ABI (P < 0.011; P < 0.003) remained predictors of mortality in our patients. The results indicate a U‐shaped association between the ABI and CV mortality in nondiabetic HD patients and showed that low and high ABI were directly associated with higher mortality of our patients.
Abstract Background and Aims Lactic acidosis (LA) is the most common cause of metabolic acidosis in hospitalised patients. LA is frequent in intensive care unit (ICU) patients with acute kidney ...injury (AKI) treated with renal replacement therapy (RRT). The aim of our study was to analyse the impact of LA on mortality. Method We conducted a retrospective observational study in a tertiary care hospital with a 12-bed ICU. During the study period of 4 years before the COVID pandemic, 2939 patients were admitted to the ICU, 503 patients were diagnosed with AKI and 210 of them required RRT. Due to missing data, we retrospectively analysed only 176 patients. LA was defined as a serum lactate concentration above 4 mmol/L on admission to the ICU. Demographic data, comorbidities, laboratory data at ICU admission and 30-day survival after ICU admission were obtained from the medical record. Survival was estimated using the Kaplan-Meier method, and factors associated with 30-day mortality were assessed in a Cox regression. Results The mean age of patients was 63.4±12.9 years, and 68.2% were men. Sixty-five (36.9%) of patients had LA. The prevalence of comorbidities prior to admission and baseline laboratory values are shown in Table 1. All patients were treated with RRT, 137 (77.8%) with continuous RRT and 39 (22.2%) with intermittent hemodialysis. The mean ICU stay was 14.6 ± 12 days, and 114 (64.8%) patients died during the observational period of 30 days. A Kaplan-Meier survival analysis showed that the survival was statistically significantly lower (log-rank; p = 0.027) in the group of patients with LA (Fig. 1). Univariate Cox regression analysis showed that LA was a significant predictor of 30-day survival (HR 1.51; 95% CI 1.038-2.197; p = 0.031). In the multivariate Cox regression analysis, which included age, gender, diabetes, hypertension, LA and C-reactive protein, only age (HR 1.029; 95% CI 1.011-1.046; p = 0.001) and LA (HR 1.515; 95% CI 1.030-2.228; p = 0.035) were independent predictors of mortality. Conclusion LA on ICU admission is an independent, highly prognostic factor for death within 30 days of admission in patients with AKI treated with RRT.
The data presented in this article are related to the research article entitled “The Diagnostic Value of Rescaled Renal Biomarkers Serum Creatinine and Serum Cystatin C and their Relation with ...Measured Glomerular Filtration Rate” (Pottel et al. (2017) 1). Data are presented demonstrating the rationale for the normalization or rescaling of serum cystatin C, equivalent to the rescaling of serum creatinine. Rescaling biomarkers brings them to a notionally common scale with reference interval 0.67–1.33. This article illustrates the correlation between rescaled biomarkers serum creatinine and serum cystatin C by plotting them in a 2-dimensional graph. The diagnostic value in terms of sensitivity and specificity with measured Glomerular Filtration Rate as the reference method is calculated per age-decade for both rescaled biomarkers. Finally, the interchangeability between detecting impaired kidney function from renal biomarkers and from the Full Age Spectrum FAS-estimating GFR-equation and measured GFR using a fixed and an age-dependent threshold is shown.
There is a pandemic of obesity worldwide and in Europe up to 30% of the adult population is already obese. Obesity is strongly related to the risk of CKD, progression of CKD, and end-stage renal ...disease (ESRD), also after adjustment for age, sex, race, smoking status, comorbidities, and laboratory tests. In the general population, obesity increases the risk of death. In nondialysis-dependent CKD patients, the association between body mass index and weight with mortality is controversial. In ESRD patients, obesity is paradoxically associated with better survival. There are only a few studies investigating changes in weight in these patients and in most weight loss was associated with higher mortality. However, it is not clear if weight change was intentional or unintentional and this is an important limitation of these studies. Management of obesity includes life-style interventions, bariatric surgery, and pharmacotherapy. In the last 2 years, a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist and GLP-1 and glucose-dependent insulinotropic polypeptide receptor agonist were shown to be effective in managing weight loss in non-CKD patients, but we are awaiting results of more definitive studies in CKD patients.
Abstract
BACKGROUND AND AIMS
Ankle-brachial index (ABI) is a marker of peripheral arterial disease and is associated with increased cardiovascular morbidity and mortality. Structural alterations in ...the arterial walls lead to functional central haemodynamic changes, potentially impacting pulse wave reflection and, consequently, myocardial perfusion.
The aim of this study was to determine the association between ABI and subendocardial viability ratio (SEVR) as a non-invasive measure of coronary perfusion in chronic haemodialysis patients.
METHOD
We measured ABI using an automated non-invasive waveform analysis device (MESI®, Slovenia) and SEVR using applanation tonometry (Sphygmocor, Atcor Medical, Sydney, Australia). All the measurements were performed on a non-dialysis day and SEVR on the non-arteriovenous fistula (non-AVF) hand. ABI was calculated as the ratio between systolic blood pressure on the non-AVF hand and systolic blood pressure on the calves of both legs. Mean ABI of both sides was used in the statistical analysis.
RESULTS
A total of 29 patients (mean age 63.6 ± 10.5 years, 69.0% male) were included. In Table 1, descriptive parameters are presented.
Of those, 4 patients (13.8%) have an ABI <0.9 and the other 25 patients (86.2%) have a normal ABI between 0.9 and 1.3. Using the independent-samples T-test, patients with a lower ABI have a statistically significant lower SEVR compared with patients with normal ABI (109 versus 142%; P = 0.039).
CONCLUSION
Low ABI is independently associated with decreased subendocardial perfusion in chronic haemodialysis patients, suggesting that both methods of ABI and SEVR measurement may reflect an atherosclerotic process in peripheral and coronary arteries.
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