Next Article in Journal
Association of Body Mass Index with Long-Term All-Cause Mortality in Patients Who Had Undergone a Vertebroplasty for a Vertebral Compression Fracture
Previous Article in Journal
Meditation and Irritable Bowel Syndrome, a Systematic Review and Meta-Analysis
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
JCM
Volume 11
Issue 21
10.3390/jcm11216518
jcm-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Serum Levels of α-Klotho, Inflammation-Related Cytokines, and Mortality in Hemodialysis Patients

by
Katarzyna Aleksandra Lisowska
1,*,
Hanna Storoniak
2,
Monika Soroczyńska-Cybula
1,
Mateusz Maziewski
1 and
Alicja Dębska-Ślizień
2
1
Department of Pathophysiology, Faculty of Medicine, Medical University of Gdańsk, 80-211 Gdańsk, Poland
2
Department of Nephrology, Transplantology and Internal Medicine, Faculty of Medicine, Medical University of Gdańsk, 80-214 Gdańsk, Poland
*
Author to whom correspondence should be addressed.
J. Clin. Med. 2022, 11(21), 6518; https://doi.org/10.3390/jcm11216518
Submission received: 16 September 2022 / Revised: 26 October 2022 / Accepted: 31 October 2022 / Published: 2 November 2022
(This article belongs to the Section Nephrology & Urology)
Review Reports Versions Notes

Abstract

:
It has been hypothesized that α-Klotho deficiency might contribute to chronic inflammation in patients with end-stage renal disease (ESRD), especially those on hemodialysis (HD). Serum Klotho levels by some authors are considered a potential predictor of cerebrovascular events. Therefore, we analyzed serum levels of α-Klotho with ELISA and inflammation-related cytokines in HD patients. Sixty-seven HD patients and 19 healthy people were recruited between November 2017 and June 2021. A Cytometric Bead Array (CBA) was used to determine the level of different cytokines: IL-12p70, TNF, IL-10, IL-6, IL-1β, and IL-8. A human Klotho ELISA kit was used to determine the level of α-Klotho in the plasma samples of HD patients. There was no difference in serum levels of α-Klotho between HD patients and healthy people. Patients had increased serum IL-6 and IL-8. Significant positive correlations existed between the concentration of α-Klotho and the serum concentrations of IL-12p70, IL-10, and IL-1β. However, in a multivariable linear regression analysis, only patients’ age was associated independently with α-Klotho level. Serum α-Klotho was not associated with higher mortality risk in HD patients. While these results draw attention to potential relationships between α-Klotho proteins and inflammatory markers in HD patients, our cross-sectional study could not confirm the pathogenic link between α-Klotho, inflammation, and cardiovascular mortality.

1. Introduction

The KLOTHO gene encoding the protein of the same name, discovered at the end of the 20th century, is one of the genes affecting animal and human life span [1]. Its knock-out mutations in mice induced osteoporosis, vascular calcification, muscle atrophy, hypoglycemia, and hyperphosphatemia and promoted reduced activity, and hearing impairment, generally leading to accelerated aging [2]. Many of the animal studies were later partially confirmed in humans. One of the best-known functions of Klotho, which belongs to the β-glucuronidase family, is its role in regulating calcium and phosphate metabolism, among others, by regulating pathways dependent on fibroblast growth factor 23 (FGF23) [3]. The kidneys are one of the organs in which Klotho expression is highest [4].
We know about three Klotho isoforms, of which α-Klotho is best known. It exists either in a form associated with the cell membrane or a secretory form (sKlotho). Secretive Klotho may arise as a result of the extracellular part being excised from the cell membrane or alternative splicing [5]. One of the essential functions of α-Klotho (both membrane and secretory) is the role of the FGF23 cofactor in increasing renal phosphate secretion [6]. sKlotho, with circulation, also goes to various tissues, inhibiting insulin-like growth factor (IGF) dependent pathways [7].
Chronic kidney disease (CKD) is associated with the loss of active nephrons in the renal parenchyma and inevitably leads to end-stage renal disease (ESRD), requiring renal replacement therapy. In addition, the course of the disease is complicated by cardiovascular disease, anemia, malnutrition, acid-base, and calcium-phosphate disorders. Furthermore, the loss of active renal parenchyma leads to hypocalcemia, hyperphosphataemia, and renal osteodystrophy, which are associated with a gradual decrease in serum sKlotho, as shown in a study by Kim et al. [8]. According to the authors, among CKD patients with low α-Klotho concentrations (below the median value of 280 pg/mL), a doubling of creatinine levels within a couple of months of observation occurs in a higher percentage than in the patients with concentrations above 280 pg/mL. α-Klotho concentration also positively correlates with the estimated glomerular filtration rate (eGFR) and calcium level [8].
In hemodialysis (HD) patients, α-Klotho levels are also associated with cardiovascular morbidity and mortality [9,10]. Otani-Takei et al. [10] showed that HD patients with low Klotho serum concentrations (<309 pg/mL) are more likely to die from cardiovascular causes. Meanwhile, HD patients with high concentrations of sKlotho have reduced occurrence of outcomes combining cardiovascular events and cardiovascular death [11]. Therefore, serum Klotho level by some authors is considered a potential predictor of cerebrovascular disease in HD patients.
ESRD patients, especially those on hemodialysis, are characterized by increased oxidative stress and inflammation, which seem to be central components of the uraemic phenotype. Chronic inflammation has been linked with cardiovascular mortality [12] and protein-energy wasting (PEW) in HD patients [13]. Inflammatory markers, especially interleukin (IL)-6, are also strong predictors of poor outcomes in ESRD patients [14]. The pathophysiology of chronic inflammation in CKD is a consequence of multiple factors, including the type of dialysis membrane, uraemic toxins, oxidative stress, cellular senescence, gut dysbiosis, hypoxia, and fluid and sodium overload [15]. It has been hypothesized that α-Klotho deficiency might contribute to increased oxidative stress and inflammation in ESRD patients. Low concentrations of α-Klotho are associated with inflammation in experimental kidney disease models [16]. Human studies show that in patients on peritoneal dialysis (PD), high concentrations of Klotho (above the median value of 329 pg/mL) are correlated with lower IL-6 levels [17]. In HD patients, the problem of the relationship between α-Klotho and inflammation is still poorly understood. Therefore, this work aimed to analyze correlations between the serum concentration of α-Klotho and cytokines associated with inflammation (IL12p70, TNF, IL-10, IL-6, IL-1β, IL-8) in HD patients. In the present study, we also investigated the predictive significance of serum levels of α-Klotho and inflammation-related cytokines in terms of survival and cardiovascular events.

2. Material and Methods

2.1. Patients

HD patients were recruited between November 2017 and June 2021. The study group comprised 67 HD patients (Table 1). Nineteen healthy people were also recruited. The Independent Bioethics Committee for Scientific Research at the Medical University of Gdańsk approved the study. We performed all the experiments following the relevant guidelines and regulations. All participants were informed about the purpose of the tests and gave written informed consent. A nephrologist thoroughly reviewed each patient’s medical chart, and data were extracted on the primary cause of CKD, prescribed medications, presence of cardiovascular disease (CVD), and other comorbid conditions, such as diabetes mellitus (DM). Laboratory data included serum concentrations of creatinine, parathormone (PTH), calcium (Ca), and phosphorus (Pi). eGFR was calculated using the CKD-EPI equation according to the KDIGO guidelines.
All HD patients had an estimated glomerular filtration rate (eGFR) below 15 min/mL/1.73 m2 and underwent four-hour hemodialysis sessions three times a week using low-flux NIPRO PES 150DL, 170DL, 210DL, or high-flux ELISIO 15H and 17H dialyzers. In addition, patients had regular dialysis adequacy assessment by measuring urea clearance using the equation Kt/V (K—urea clearance, t—time on dialysis, V—volume of distribution). Healthy people underwent a routine health examination, had no history of medical disease, and were not taking regular medication.
In 13 patients, the primary cause of chronic kidney disease was glomerulonephritis (GN), in 25—diabetic nephropathy (DN), in 13—ischemic nephropathy (IN), in 4—hypertensive nephropathy (HN), in 6—adult polycystic kidney disease (ADPKD). In two patients, the primary cause of CKD was unknown. Two patients had obstructive nephropathy, and two had granulomatosis with polyangiitis (GPA). None of the patients suffered from active infection, inflammation, malnutrition, malignancy, or blood loss during the study. They did not receive steroids or immunosuppressive agents.
Blood samples were collected from each patient before the HD session into gel-separator serum tubes to collect serum to assess concentrations of cytokines and α-Klotho. We stored serum samples at −80 °C as recommended by other authors [18,19].

2.2. Cytokine Measurement in Plasma Samples

BD™ Cytometric Bead Array (CBA) Human Inflammatory Cytokines Kit (Becton, Dickinson and Company, Franklin Lakes, NJ, USA) was used according to the manufacturer’s protocol to determine the level of different cytokines, i.e., IL-12p70, TNF, IL-10, IL-6, IL-1β, and IL-8, in the plasma samples of HD patients. The detection range for all measured cytokines was between 20 and 5000 pg/mL. We performed quantitative cytometric fluorescence analysis with the FACScan cytometer (Becton, Dickinson and Company, Franklin Lakes, NJ, USA). Cytokine concentrations were analyzed with the use of BD™ CBA software (Becton, Dickinson and Company, Franklin Lakes, NJ, USA).

2.3. Detection of α-Klotho Alpha in Plasma Samples

Human KL(Klotho) ELISA Kit (Wuhan Fine Biotech Co., Wuhan, China) was used according to the manufacturer’s protocol to determine the level of α-Klotho in the plasma samples of HD patients. The effective measurement range of this assay was between 7.8 and 500 pg/mL. The density of the yellow color was proportional to the target amount of sample captured in the 96-well plate, and the O.D. absorbance was read at 450 nm absorbance in Epoch™ Microplate Spectrophotometer (Agilent Technologies, Inc., Santa Clara, CA, USA).

2.4. Outcome Measurements

The primary outcomes included all-cause mortality, cardiovascular mortality, or a combined outcome that included cardiovascular death or non-fatal cardiovascular events, defined as myocardial infarction (MI), stroke, major arterial/venous thrombotic episode, coronary revascularization, atrial fibrillation (AF), or decompensated heart failure (HF). Cardiovascular death was defined as death from any cardiovascular event. Cardiovascular events and cause of death were assessed by the attending physicians, who were unaware of serum α-Klotho. Censoring was performed either on the date of the first occurrence of each studied endpoint or on 30 June 2022. The patient’s usual medications, including antihypertensive agents, erythropoiesis-stimulating agents (ESAs), or alfacalcidol, were continued during the observation period.

2.5. Analysis and Statistics

The concentration of α-Klotho was calculated with GraphPad Prism 9 (GraphPad Software Inc., San Diego, CA, USA). GraphPad Prism 9 was also used to perform statistical analyses. The Kolmogorov-Smirnov and Lilliefors tests were used for testing normality. Significance tests were chosen according to data distribution with a significance level of p < 0.05. Comparisons between the two groups were assessed with the nonparametric Mann-Whitney U test for continuous variables. Correlations between continuous variables were done using the Spearman Rank Correlation test. Cox regression models were used to analyze the relationships between the primary outcomes and the serum levels of α-Klotho and cytokines in HD patients. Data are expressed as medians with minimum and maximum results, percentages, or hazard ratios with 95% confidence intervals (95% CI).

3. Results

3.1. Baseline Demographic, Clinical, and Laboratory Findings

The clinical information about 67 HD patients, including serum concentrations of creatinine, PTH, Ca, Pi, levels of cytokines IL-12p70, TNF, IL-10, IL-6, IL-1β, IL-8, and α-Klotho are shown as mean and median values in Table 1. Fifty-eight patients (87%) patients were diagnosed with chronic heart failure (CHF). Sixty-three (94%) patients were suffering from hypertension. In addition, 36 (55%) patients were diagnosed with DM. In 25 patients, DN was a primary cause of CKD. 36 (54%) of patients received alfacalcidol 0.25 µg daily.
There was no significant difference in the serum concentration of α-Klotho between healthy people and HD patients. However, HD patients had higher IL-6 and IL-8 concentrations than healthy people (Table 1).
The primary cause of CKD or the type of DM did not influence the serum concentration of α-Klotho (data not shown).

3.2. Factors Associated with α-Klotho Levels

Bivariate correlation analyses revealed that there was a significant negative correlation between the concentration of serum α-Klotho and patients’ age (r = −0.268, p = 0.028) and the serum concentration of PTH (r = −0.290, p = 0.017) (Table 2). No correlation has been found between α-Klotho and Ca or Pi. The serum concentration of α-Klotho was positively correlated with serum IL-12p70 (r = 0.250, p = 0.041), IL-10 (r = 0.333, p = 0.006), and IL-1β (r = 0.436, p < 0.001). A multiple linear regression analysis was conducted to identify further factors independently associated with Klotho. Age, PTH, IL-12p70, and IL-10, which were significantly correlated with α-Klotho in bivariate correlation analyses, were used for the analysis. Only age was associated independently with patients’ Klotho levels (Table 3).
As for other relationships between inflammatory markers and clinical parameters, the concentration of IL-8 was negatively correlated with HD time (r = −0.278, p = 0.023) (Table 2). Creatinine, PTH, and Pi levels were negatively correlated with patients’ age. Other correlations are shown in Table 2.

3.3. Factors Associated with Cardiovascular Events and Mortality

Fourteen patients died within the median follow-up period of 7 months. Nine patients died because of cardiovascular events. Three patients developed an infection and died because of sepsis. Two patients died because of unknown reasons and died out of the hospital. The Cox regression analyses revealed several factors associated with cardiovascular events, cardiovascular mortality, and all-cause mortality (Table 4). Serum creatinine levels were predictive for cardiovascular events (HR 0.726, 95% CI 0.575–0.902, p = 0.005), cardiovascular mortality (HR 0.517, 95% CI 0.313–0.807, p = 0.006), and all-cause mortality (HR 0.577, 95% CI 0.392–0.816, p = 0.003). eGFR was predictive for cardiovascular death (HR 1.25, 95% CI 1.07–1.46, p = 0.003) and all-cause mortality (HR 1.20, 95% CI 1.05–1.36, p = 0.003). DN was predictive for cardiovascular events (HR 2.73, 95% CI 1.31–6.11, p = 0.009).

4. Discussion

The history of Klotho is associated with discovering the relationship between its expression and aging in mice [1]. Among the three isoforms, the most important is α-Klotho, which occurs in the kidney in high concentrations. It is produced mainly in the distal nephron tubules and is associated with calcium-phosphate metabolism [3]. Over the years, many publications have emerged showing significant correlations between the concentration of α-Klotho in the blood of CKD patients and the progression of the disease [8] and cardiovascular complications, especially in HD patients [9,10]. Meanwhile, the relationship between α-Klotho and inflammatory markers in HD patients is still unclear. Therefore, our study compared serum levels of selected cytokines and α-Klotho between HD patients and healthy people of similar age.
Some studies show that HD patients have high serum IL-1, IL-6, IL-8, and TNF-α [20], produced mainly by mononuclear cells [21]. According to some authors, IL-6, in particular, is recognized as a strong predictor of poor outcomes in ESRD patients [14]. In our study, HD patients had higher IL-6 and IL-8 concentrations than healthy people but not IL-1β or TNF-α. In addition, there was no difference between patients and control in serum levels of α-Klotho. Until recently, studies showed a significant positive correlation between soluble α-Klotho and eGFR in patients with CKD [8,22]. According to some authors, α-Klotho expression is also decreased in other tissues, including parathyroid glands [23] or vascular smooth muscles [24]. However, not all authors agree on whether α-Klotho’s serum levels in HD patients reflect its tissue deficiencies. For example, Seiler et al. [25] analyzed plasma levels of Klotho in a large cohort of patients in CKD stages 2–4 and found no decline as the disease progressed. The authors saw no correlation between Klotho levels and eGFR or parameters associated with calcium-phosphate metabolism. Yildirim et al. [26] have demonstrated that HD and PD patients have higher serum α-Klotho than healthy people. In a recent study by Gamrot et al. [27], mean serum α-Klotho was higher in children with CKD on dialysis than in conservatively treated children. Drüeke et al. [28] suggested that there might be a difference in Klotho levels between patients supplemented with vitamin D and those not receiving vitamin D. In our study, approximately half of the patients were supplemented with alfacalcidol. However, it did not influence α-Klotho serum concentrations. As in the study by Seiler et al. [25], the α-Klotho level was negatively correlated with HD patients’ age, which was confirmed by multiple linear regression analysis. The correlation matrix showed no relationships between serum α-Klotho and any variables associated with CKD, including creatinine, eGFR, or calcium and phosphorus concentrations, except for PTH. Similar results were reported by Wei et al. [11], who also saw no correlation between serum Klotho and Ca, Pi, or PTH in HD patients despite a much larger study group. Buiten et al. [29] demonstrated a correlation between sKlotho only with PTH in HD patients.
Seiler et al. [25] stressed in their study that a reliable measurement of circulating Klotho has become available only recently, with more sensitive and specific ELISA tests. Therefore, we must consider that changes in the serum levels of α-Klotho in HD patients are not necessarily directly related to disease progression. It is also possible that in HD patients, the eGFR is already too low and the calcium-phosphate balance too disturbed to demonstrate any relationship with Klotho levels. Since there is no relationship between serum α-Klotho and calcium-phosphate balance, we can assume that the clinical impact of soluble Klotho might not be the same as tissue Klotho.
In the latest studies, soluble α-Klotho has been shown to be significantly associated with well-recognized inflammatory biomarkers, e.g., uric acid (UA) [30,31], C-reactive protein (CRP), white blood cell (WBC) count, and mean platelet volume (MPV) [31]. In PD patients, high concentrations of Klotho (above the median value of 329 pg/mL) were associated with lower IL-6 levels [17]. In children with CKD, no correlation was observed between serum α-Klotho or TNF-α concentration and any measured anthropometric and laboratory parameters [27]. In our study, α-Klotho also positively correlated with IL-12p70, IL-10, and IL-1β but not with TNF or IL-6. Downregulation of renal α-Klotho expression has been shown to increase kidney inflammation [16] and induce renal fibrosis [32] in animal models. In mice that suffered unilateral renal ischemia and reperfusion injury (IRI), recombinant Klotho prevented an increase in serum IL-6, IL-1β, and TNF-α levels [33]. These processes are related to the role of Klotho in reducing the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) [34], suppressed TNF-induced NF-kappaB activation [35], and upregulated anti-inflammatory IL-10 [34]. Thus, the anti-inflammatory role of α-Klotho could explain a positive correlation with anti-inflammatory IL-10 in our study group. However, till now, such an association was only confirmed in patients with established cardiovascular disease (CVD), whose low Klotho concentrations accompanied low IL-10 levels [36].
However, what is surprising is the positive correlation between α-Klotho and IL-1β and IL-12p70, which have a pro-inflammatory effect. IL-12 is a pro-inflammatory cytokine that induces the production of interferon-γ (IFN-γ) by T helper 1 (Th1) cells associated with cell-mediated immunity. Studies showed that HD patients exhibit an increased percentage of Th1 cells compared with healthy controls, and their monocytes produce high levels of IL-12 [37]. IL-1β, also known as leukocytic pyrogen, is an essential mediator of the inflammatory response associated with acute symptoms such as fever and hypotension in HD patients [38]. Both cytokines are associated with attenuated inflammatory responses in ESRD, aggravated by high uremic toxins and repeated contact with the dialysis membrane [20]. Therefore, their positive correlation with α-Klotho draws attention to its potential, not yet described, role in promoting inflammation. The relationship between IL-10 and IL-1β levels is most likely the result of monocytes and macrophages responding to high levels of pro-inflammatory cytokines. In particular, macrophages produce IL-10 in a negative feedback loop to reduce uncontrolled inflammatory cytokine production during, for example, infection [39]. By binding with its receptor on cells of innate immunity, IL-10 inhibits the release of pro-inflammatory cytokines and decreases antigen presentation and phagocytosis. Therefore, it would be expected that the higher IL-10 level would accompany high IL-1 levels. In our study, those two variables were correlated.
Several articles have reported a significant association between serum Klotho and mortality in HD patients [9,10,11,40]. In our study, serum α-Klotho levels did not influence cardiovascular events or all-cause mortality in HD patients. In physiologic conditions, healthy kidneys maintain soluble Klotho levels [41]. However, as mentioned earlier, other organs may participate in maintaining soluble α-Klotho in ESRD, and high α-Klotho expression has been found in the parathyroid gland [23] and vascular smooth muscles [24]. In animals, high tissue α-Klotho has also been reported in the choroid plexus [42], while in humans it has been detected in cerebrospinal fluid [43]. While there is one KLOTHO gene, three isoforms of α-Klotho exist, the transmembrane form, a shed soluble form, and a truncated soluble form produced by alternative splicing. Its soluble form results from direct secretion by the cell of truncated form or from cleavage of the extracellular domain of the full-length protein [5]. The different tissue locations of α-Klotho and the different mechanisms of soluble Klotho production bring into question the relationship between protein expression in the kidney and its amount in the blood in CKD patients [11,25,26,27]. The lack of relationship between serum α-Klotho and fatal or non-fatal cardiovascular events could be explained by several factors. First, CVD starts to develop in the early stages of CKD. Second, many factors are associated with CVD progress, including smoking, obesity, diabetes, or hypertension. Third, serum α-Klotho simply may have no independent influence on CVD development in HD patients. Several authors have obtained similar results. For example, Buiten et al. [29] reported that serum sKlotho in patients in CKD stage 5D was not independently associated with cardiovascular disease. Moreover, HD patients with a low sKlotho level (<460 pg/mL) did show coronary artery disease (CAD) and left ventricular (LV) dysfunction more frequently. Seiler et al. [25] also demonstrated that sKlotho did not predict any cardiovascular outcomes, including death.
At present, we do not know what the “normal” serum level of α-Klotho is. Presently, there is no standardized assay to measure circulating Klotho in humans. It is also possible that the distinction and characterization of the soluble forms of α-Klotho may be necessary to fully unveil the role of Klotho in CKD. Many authors have used median splits to demonstrate its clinical relevance in CKD or CVD. However, the problem with median splits is that when a continuous variable is categorized, every value above the median, for example, is considered equal. Hence, it is not surprising that the results from different centers regarding the relationship between serum Klotho levels and clinical parameters in dialysis patients do not coincide.
The risk of CVD in CKD patients is far greater than in the general population, with CVD mortality in HD patients 10 to 20 times higher than in the general population [44]. However, the usefulness of creatinine or eGFR for predicting cardiovascular outcomes in CKD patients is still controversial. In our study, serum creatinine levels, eGFR, and diabetes were predictive of cardiovascular events and death. According to the latest meta-analysis by Matsushita et al. [45], creatinine-based eGFR and albuminuria independently improved the prognosis of incident cardiovascular outcomes. Another option is to measure GFR using other filtration markers, such as cystatin C (eGFRcys). Recently, Lees et al. [46] demonstrated that eGFRcys is more strongly associated with CVD and mortality than creatinine-based measurement. Therefore, eGFR should be considered for cardiovascular prediction, especially when it is already assessed for clinical purposes. The latest studies also show that diabetes is associated with a risk for CV events in HD [47], which is in line with our results.
To sum up, there was no difference in serum levels of α-Klotho between HD patients and healthy people, though, HD patients had increased serum IL-6 and IL-8. Significant positive correlations existed between the concentration of α-Klotho and the serum concentration of IL-12p70, IL-10, and IL-1β. However, in a multivariable linear regression analysis, only patients’ age was associated independently with α-Klotho level. Serum α-Klotho was not associated with higher mortality risk in HD patients.
In summary, these associations, which we demonstrated in our study, draw attention to the potential relationship between α-Klotho levels, the inflammation status, and mortality of HD patients. Based on the present state of knowledge, serum α-Klotho measurement does not appear to be helpful in patients with ESRD to predict mortality. However, our cross-sectional study has several limitations, including the relatively small size of the study, the Polish origin of the dialysis population, and a small number of deaths during the observation period. Therefore, these results may not be generalized. Consequently, further studies are necessary to clarify the relationship between α-Klotho, inflammation, and mortality in hemodialysis patients. In addition, the development of a standardized assay is essential to measure circulating α-Klotho and to demonstrate its clinical relevance.

Author Contributions

Conceptualization, K.A.L. and H.S.; methodology, K.A.L., M.S.-C. and M.M.; formal analysis, K.A.L.; investigation, K.A.L. and M.S.-C.; resources, K.A.L. and A.D.-Ś.; data curation, K.A.L. and H.S.; writing—original draft preparation, K.A.L.; writing—review & editing, K.A.L. and H.S.; visualization, K.A.L.; supervision, K.A.L.; project administration, K.A.L.; funding acquisition, K.A.L. and A.D.-Ś. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the statutory funds of the Medical University of Gdańsk 02-0004/07 (granted to A.D.-Ś.) and the Excellence Initiative research grant 01-0510/08 (granted to K.A.L).

Institutional Review Board Statement

The Independent Bioethics Committee for Scientific Research at the Medical University of Gdańsk approved the study (consent no. NKBBN/602/2019), received on 6 November 2019). The study was conducted in accordance with the Declaration of Helsinki.

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

All cytometric analyses were performed using the instruments acquired for the Cellular Function and Pathology Imaging Network of the Medical University of Gdańsk and the University of Gdańsk.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Kuro-O, M.; Matsumura, Y.; Aizawa, H.; Kawaguchi, H.; Suga, T.; Utsugi, T.; Ohyama, Y.; Kurabayashi, M.; Kaname, T.; Kume, E.; et al. Mutation of the mouse klotho gene leads to a syndrome resembling ageing. Nature 1997, 390, 45–51. [Google Scholar] [CrossRef] [PubMed]
  2. Kuro-O, M. Klotho and aging. Biochim. Biophys. Acta 2009, 1790, 1049–1058. [Google Scholar] [CrossRef] [PubMed]
  3. Kurosu, H.; Ogawa, Y.; Miyoshi, M.; Yamamoto, M.; Nandi, A.; Rosenblatt, K.P.; Baum, M.G.; Schiavi, S.; Hu, M.-C.; Moe, O.W.; et al. Regulation of fibroblast growth factor-23 signaling by klotho. J. Biol. Chem. 2006, 281, 6120–6123. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  4. Olauson, H.; Mencke, R.; Hillebrands, J.-L.; Larsson, T.E. Tissue expression and source of circulating αKlotho. Bone 2017, 100, 19–35. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  5. Matsumuraab, Y.; Aizawaab, H.; Iidaac, T.S.; Nagaibd, R.; Kuro-O, M.; Ichinabeshimaade, Y. Identification of the human klotho gene and its two transcripts encoding membrane and secreted klotho protein. Biochem. Biophys. Res. Commun. 1998, 242, 6260–6630. [Google Scholar] [CrossRef]
  6. Urakawa, I.; Yamazaki, Y.; Shimada, T.; Iijima, K.; Hasegawa, H.; Okawa, K.; Fujita, T.; Fukumoto, S.; Yamashita, T. Klotho converts canonical FGF receptor into a specific receptor for FGF23. Nature 2006, 444, 770–774. [Google Scholar] [CrossRef]
  7. Yamamoto, M.; Clark, J.D.; Pastor, J.V.; Gurnani, P.; Nandi, A.; Kurosu, H.; Miyoshi, M.; Ogawa, Y.; Castrillon, D.H.; Rosenblatt, K.P.; et al. Regulation of oxidative stress by the anti-aging hormone klotho. J. Biol. Chem. 2005, 280, 38029–38034. [Google Scholar] [CrossRef] [Green Version]
  8. Kim, H.R.; Nam, B.Y.; Kim, D.W.; Kang, M.W.; Han, J.-H.; Lee, M.J.; Shin, D.H.; Doh, F.M.; Koo, H.M.; Ko, K.I.; et al. Circulating α-klotho levels in CKD and Circulating α-klotho levels in CKD and relationship to progression. Am. J. Kidney Dis. 2013, 61, 899–909. [Google Scholar] [CrossRef]
  9. Marçais, C.; Maucort-Boulch, D.; Drai, J.; Dantony, E.; Carlier, M.-C.; Blond, E.; Genet, L.; Kuentz, F.; Lataillade, D.; Legrand, E.; et al. Circulating Klotho Associates with Cardiovascular Morbidity and Mortality During Hemodialysis. J. Clin. Endocrinol. Metab. 2017, 102, 3154–3161. [Google Scholar] [CrossRef] [Green Version]
  10. Otani-Takei, N.; Masuda, T.; Akimoto, T.; Honma, S.; Watanabe, Y.; Shiizaki, K.; Miki, T.; Kusano, E.; Asano, Y.; Kuro-O, M.; et al. Association between Serum Soluble Klotho Levels and Mortality in Chronic Hemodialysis Patients. Int. J. Endocrinol. 2015, 2015, 406269. [Google Scholar] [CrossRef]
  11. Wei, H.; Li, H.; Song, X.; Du, X.; Cai, Y.; Li, C.; Dong, L.; Dong, J. Serum klotho: A potential predictor of cerebrovascular disease in hemodialysis patients. BMC Nephrol. 2019, 20, 63. [Google Scholar] [CrossRef] [Green Version]
  12. Himmelfarb, J.; Stenvinkel, P.; Ikizler, T.A.; Hakim, R.M. The elephant in uremia: Oxidant stress as a unifying concept of cardiovascular disease in uremia. Kidney Int. 2002, 62, 1524–1538. [Google Scholar] [CrossRef] [Green Version]
  13. Jankowska, M.; Cobo, G.; Lindholm, B.; Stenvinkel, P. Inflammation and Protein-Energy Wasting in the Uremic Milieu. Contrib. Nephrol. 2017, 191, 58–71. [Google Scholar] [CrossRef]
  14. Sun, J.; Axelsson, J.; Machowska, A.; Heimbürger, O.; Bárány, P.; Lindholm, B.; Lindström, K.; Stenvinkel, P.; Qureshi, A.R. Biomarkers of Cardiovascular Disease and Mortality Risk in Patients with Advanced CKD. Clin. J. Am. Soc. Nephrol. 2016, 11, 1163–1172. [Google Scholar] [CrossRef] [Green Version]
  15. Cobo, G.; Lindholm, B.; Stenvinkel, P. Chronic inflammation in end-stage renal disease and dialysis. Nephrol. Dial. Transplant. 2018, 33, iii35–iii40. [Google Scholar] [CrossRef] [Green Version]
  16. Zhao, Y.; Banerjee, S.; Dey, N.; LeJeune, W.S.; Sarkar, P.S.; Brobey, R.; Rosenblatt, K.P.; Tilton, R.G.; Choudhary, S. Klotho depletion contributes to increased inflammation in kidney of the db/db mouse model of diabetes via RelA (serine)536 phosphorylation. Diabetes 2011, 60, 1907–1916. [Google Scholar] [CrossRef] [Green Version]
  17. Oh, H.J.; Nam, B.Y.; Lee, M.J.; Kim, C.H.; Koo, H.M.; Doh, F.M.; Han, J.H.; Kim, E.J.; Han, J.S.; Park, J.T.; et al. Decreased circulating klotho levels in patients undergoing dialysis and relationship to oxidative stress and inflammation. Perit. Dial. Int. 2015, 35, 43–51. [Google Scholar] [CrossRef] [Green Version]
  18. Graham, C.; Chooniedass, R.; Stefura, W.P.; Lotoski, L.; Lopez, P.; Befus, A.D.; Becker, A.B.; HayGlass, K.T. Stability of pro- and anti-inflammatory immune biomarkers for human cohort studies. J. Transl. Med. 2017, 15, 53. [Google Scholar] [CrossRef] [Green Version]
  19. Verberk, I.M.; Nossent, E.J.; Bontkes, H.J.; Teunissen, C.E. Pre-analytical sample handling effects on blood cytokine levels: Quality control of a COVID-19 biobank. Biomark. Med. 2021, 15, 987–997. [Google Scholar]
  20. Rysz, J.; Banach, M.; Ciałkowska-Rysz, A.; Stolarek, R.; Barylski, M.; Drozdz, J.; Okonski, P. Blood serum levels of IL-2, IL-6, IL-8, TNF-alpha and IL-1beta in patients on maintenance hemodialysis. Cell. Mol. Immunol. 2006, 3, 151–154. [Google Scholar]
  21. Girndt, M.; Köhler, H.; Schiedhelm-Weick, E.; Schlaak, J.F.; Büschenfelde, K.-H.M.Z.; Fleischer, B. Production of interleukin-6, tumor necrosis factor alpha and interleukin-10 in vitro correlates with the clinical immune defect in chronic hemodialysis patients. Kidney Int. 1995, 47, 559–565. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  22. Wang, Q.; Su, W.; Shen, Z.; Wang, R. Correlation between Soluble α-Klotho and Renal Function in Patients with Chronic Kidney Disease: A Review and Meta-Analysis. Biomed. Res. Int. 2018, 2018, 9481475. [Google Scholar] [CrossRef] [PubMed]
  23. Komaba, H.; Goto, S.; Fujii, H.; Hamada, Y.; Kobayashi, A.; Shibuya, K.; Tominaga, Y.; Otsuki, N.; Nibu, K.-I.; Nakagawa, K.; et al. Depressed expression of Klotho and FGF receptor 1 in hyperplastic parathyroid glands from uremic patients. Kidney Int. 2010, 77, 232–238. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  24. Lim, K.; Lu, T.-S.; Molostvov, G.; Lee, C.; Lam, F.; Zehnder, D.; Hsiao, L.-L. Vascular Klotho deficiency potentiates the development of human artery calcification and mediates resistance to fibroblast growth factor 23. Circulation 2012, 125, 2243–2255. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  25. Seiler, S.; Wen, M.; Roth, H.J.; Fehrenz, M.; Flügge, F.; Herath, E.; Weihrauch, A.; Fliser, D.; Heine, G.H. Plasma Klotho is not related to kidney function and does not predict adverse outcome in patients with chronic kidney disease. Kidney Int. 2013, 83, 121–128. [Google Scholar] [CrossRef] [Green Version]
  26. Yildirim, M.; Acikgoz, S.B.; Genc, A.B.; Yaylaci, S.; Dheir, H.; Sipahi, S. The levels of inflammatory biomarkers in hemodialysis and peritoneal dialysis patients. Rev. Assoc. Med. Bras. 2021, 67, 718–723. [Google Scholar] [CrossRef]
  27. Gamrot, Z.; Adamczyk, P.; Świętochowska, E.; Roszkowska-Bjanid, D.; Gamrot, J.; Szczepanska, M. Tumour necrosis factor alpha (TNFα) and alpha-Klotho (αKL) in children and adolescents with chronic kidney disease (CKD). Endokrynol. Pol. 2021, 72, 625–633. [Google Scholar] [CrossRef]
  28. Drüeke, T.B.; Massy, Z.A. Circulating Klotho levels: Clinical relevance and relationship with tissue Klotho expression. Kidney Int. 2013, 83, 13–15. [Google Scholar] [CrossRef] [Green Version]
  29. Buiten, M.S.; De Bie, M.K.; Krijger, A.B.-D.; Van Dam, B.; Dekker, F.; Jukema, J.W.; Rabelink, T.J.; Rotmans, J.I. Soluble Klotho is not independently associated with cardiovascular disease in a population of dialysis patients. BMC Nephrol. 2014, 15, 197. [Google Scholar] [CrossRef] [Green Version]
  30. Lee, H.-J.; Choi, J.-Y.; Lee, J.; Kim, D.; Min, J.-Y.; Min, K.-B. Association between serum uric acid and α-klotho protein levels in the middle-aged population. Aging 2022, 14, 2537–2547. [Google Scholar] [CrossRef]
  31. Wu, S.-E.; Chen, W.-L. Soluble klotho as an effective biomarker to characterize inflammatory states. Ann. Med. 2022, 54, 1520–1529. [Google Scholar] [CrossRef]
  32. Sugiura, H.; Yoshida, T.; Shiohira, S.; Kohei, J.; Mitobe, M.; Kurosu, H.; Kuro-O, M.; Nitta, K.; Tsuchiya, K. Reduced Klotho expression level in kidney aggravates renal interstitial fibrosis. Am. J. Physiol. Renal Physiol. 2012, 302, F1252–F1264. [Google Scholar] [CrossRef]
  33. Junho, C.V.C.; González-Lafuente, L.; Neres-Santos, R.S.; Navarro-García, J.A.; Rodríguez-Sánchez, E.; Ruiz-Hurtado, G.; Carneiro-Ramos, M.S. Klotho relieves inflammation and exerts a cardioprotective effect during renal ischemia/reperfusion-induced cardiorenal syndrome. Biomed. Pharmacother. 2022, 153, 113515. [Google Scholar] [CrossRef]
  34. Mytych, J.; Romerowicz-Misielak, M.; Koziorowski, M. Klotho protects human monocytes from LPS-induced immune impairment associated with immunosenescent-like phenotype. Mol. Cell. Endocrinol. 2018, 470, 1–13. [Google Scholar] [CrossRef]
  35. Maekawa, Y.; Ishikawa, K.; Yasuda, O.; Oguro, R.; Hanasaki, H.; Kida, I.; Takemura, Y.; Ohishi, M.; Katsuya, T.; Rakugi, H. Klotho suppresses TNF-alpha-induced expression of adhesion molecules in the endothelium and attenuates NF-kappaB activation. Endocrine 2009, 35, 341–346. [Google Scholar] [CrossRef]
  36. Martín-Núñez, E.; Donate-Correa, J.; Ferri, C.; López-Castillo, Á.; Delgado-Molinos, A.; Hernández-Carballo, C.; Pérez-Delgado, N.; Rodríguez-Ramos, S.; Cerro-López, P.; Tagua, V.G.; et al. Association between serum levels of Klotho and inflammatory cytokines in cardiovascular disease: A case-control study. Aging 2020, 12, 1952–1964. [Google Scholar] [CrossRef]
  37. Sester, U.; Sester, M.; Hauk, M.; Kaul, H.; Köhler, H.; Girndt, M. T-cell activation follows Th1 rather than Th2 pattern in haemodialysis patients. Nephrol. Dial. Transplant. 2000, 15, 1217–1223. [Google Scholar] [CrossRef] [Green Version]
  38. Yu, J.; Chen, X.; Li, Y.; Wang, Y.; Cao, X.; Liu, Z.; Shen, B.; Zou, J.; Ding, X. Pro-inflammatory cytokines as potential predictors for intradialytic hypotension. Ren. Fail. 2021, 43, 198–205. [Google Scholar] [CrossRef]
  39. Iyer, S.S.; Cheng, G. Role of interleukin 10 transcriptional regulation in inflammation and autoimmune disease. Crit. Rev. Immunol. 2012, 32, 23–63. [Google Scholar] [CrossRef] [Green Version]
  40. Memmos, E.; Sarafidis, P.; Pateinakis, P.; Tsiantoulas, A.; Faitatzidou, D.; Giamalis, P.; Vasilikos, V.; Papagianni, A. Soluble Klotho is associated with mortality and cardiovascular events in hemodialysis. BMC Nephrol. 2019, 20, 217. [Google Scholar] [CrossRef] [Green Version]
  41. Lindberg, K.; Amin, R.; Moe, O.W.; Hu, M.-C.; Erben, R.G.; Wernerson, A.; Lanske, B.; Olauson, H.; Larsson, T.E. The kidney is the principal organ mediating klotho effects. J. Am. Soc. Nephrol. 2014, 25, 2169–2175. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  42. German, D.C.; Khobahy, I.; Pastor, J.; Kuro-O, M.; Liu, X. Nuclear localization of Klotho in brain: An anti-aging protein. Neurobiol. Aging. 2012, 33, 1483.e25–1483.e30. [Google Scholar] [CrossRef] [PubMed]
  43. Semba, R.D.; Moghekar, A.R.; Hu, J.; Sun, K.; Turner, R.; Ferrucci, L.; O’Brien, R. Klotho in the cerebrospinal fluid of adults with and without Alzheimer’s disease. Neurosci. Lett. 2014, 558, 37–40. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  44. Foley, R.N.; Parfrey, P.S.; Sarnak, M.J. Clinical epidemiology of cardiovascular disease in chronic renal disease. Am. J. Kidney Dis. 1998, 32, S112–S119. [Google Scholar] [CrossRef]
  45. Matsushita, K.; Coresh, J.; Sang, Y.; Chalmers, J.; Fox, C.; Guallar, E.; Jafar, T.; Jassal, S.K.; Landman, G.W.D.; Muntner, P.; et al. Estimated glomerular filtration rate and albuminuria for prediction of cardiovascular outcomes: A collaborative meta-analysis of individual participant data. Lancet Diabetes Endocrinol. 2015, 3, 514–525. [Google Scholar] [CrossRef] [Green Version]
  46. Lees, J.S.; Welsh, C.E.; Celis-Morales, C.A.; Mackay, D.; Lewsey, J.; Gray, S.R.; Lyall, D.M.; Cleland, J.G.; Gill, J.M.R.; Jhund, P.S.; et al. Glomerular filtration rate by differing measures, albuminuria and prediction of cardiovascular disease, mortality and end-stage kidney disease. Nat. Med. 2019, 25, 1753–1760. [Google Scholar] [CrossRef]
  47. De Lima, J.J.G.; Gowdak, L.H.W.; David-Neto, E.; Bortolotto, L.A. Diabetes, Cardiovascular Disease, and Cardiovascular Risk in Patients with Chronic Kidney Disease. High Blood Press. Cardiovasc. Prev. 2021, 28, 159–165. [Google Scholar] [CrossRef]
Table
Table 1. Comparison of basic clinical parameters and serum concentrations of HD patients and healthy people.
Table 1. Comparison of basic clinical parameters and serum concentrations of HD patients and healthy people.
Healthy People (n = 19)HD Patients (n = 67)p Value
Age (years)70 (37, 87)69 (36, 89)0.613
HD time (months)n.a.28 (0.5, 169)n.a.
Creatinine (mg/dL)n.a.6.3 (2.71, 10.38)n.a.
eGFR (min/mL/1.73 m2)n.a.7 (4, 22)n.a.
Kt/Vn.a.1.5 (0.74, 2.37)n.a.
PTH (pg/mL)n.a.356 (44.5, 4276)n.a.
Ca (mg/dL)n.a.8.7 (6.5, 10.8)n.a.
Pi (mg/dL)n.a.5.5 (2.4, 10.5)n.a.
IL-12p70 (pg/mL)2.7 (1.05, 12.74)2.45 (0, 108.95)0.737
TNF (pg/mL)2.59 (0.84, 5.22)2.5 (0, 127.65)0.568
IL-10 (pg/mL)2.65 (0.72, 6.15)2.8 (1.4, 21.88)0.104
IL-6 (pg/mL)4.08 (2.23, 22.57)10.3 (3.45, 805.45)<0.001
IL-1β (pg/mL)1.83 (0, 3.33)1.75 (0, 18.24)0.844
IL-8 (pg/mL)13.56 (9.59, 911.66)38.8 (10.4, 5000)0.001
α-Klotho (pg/mL)8.74 (1.33, 60.82)6.96 (0.45, 127.1)0.451
Data are presented as median with minimum and maximum. The results in bold are statistically significant, Mann-Whitney U test, p < 0.05. eGFR—estimated glomerular filtration rate, PTH—parathormone, Ca—calcium, Pi—phosphorus, n.a.—not applicable.
Table
Table 2. Correlations between serum concentrations of α-Klotho, patients’ clinical parameters, and serum cytokines.
Table 2. Correlations between serum concentrations of α-Klotho, patients’ clinical parameters, and serum cytokines.
AgeHD TimeCreGFRKt/VPTHCaPiIL-12TNFIL-10IL-6IL-1IL-8α-KL
Age1.000−0.186−0.3580.192−0.194−0.2530.106−0.330−0.138−0.076−0.1780.047−0.0480.053−0.268
HD time 1.0000.178−0.2860.4150.4490.036−0.106−0.0030.0420.0450.028−0.004−0.278−0.004
Cr 1.000−0.6680.2940.143−0.2230.408−0.122−0.064−0.119−0.004−0.0800.189−0.108
eGFR 1.000−0.353−0.3270.108−0.4150.125−0.0530.0940.121−0.069−0.1840.075
Kt/V 1.0000.228−0.0070.0640.0140.083−0.088−0.125−0.050−0.020−0.138
PTH 1.000−0.1460.242−0.0170.165−0.0730.024−0.0260.081−0.290
Ca 1.000−0.2170.1130.018−0.038−0.1620.140−0.1430.117
Pi 1.0000.0260.2070.0340.0740.1580.186−0.025
IL-12 1.0000.3840.4240.2350.421−0.0280.250
TNF 1.0000.2860.1340.179−0.018−0.191
IL-10 1.0000.3860.546−0.0220.333
IL-6 1.0000.1950.3640.090
IL-1 1.000−0.1100.436
IL-8 1.000−0.123
α-KL 1.000
The results in bold are statistically significant, bivariate Spearman Rank Correlation test, p < 0.05. Cr—creatinine, α-KL—α-Klotho.
Table
Table 3. Multivariable linear regression analyses for α-Klotho.
Table 3. Multivariable linear regression analyses for α-Klotho.
VariableEstimateStandard Error95% CIp Value
Age−0.5510.271−1.09 to −0.008170.047
PTH−0.007790.00491−0.0176 to 0.002020.118
IL-12−0.06470.167−0.399 to 0.2700.700
IL-10−0.5450.997−2.54 to 1.450.587
IL-11.711.15−0.601 to 4.010.144
The results in bold are statistically significant (p < 0.05). CI—confidence interval.
Table
Table 4. Cox regression analyses of cardiovascular events, cardiovascular mortality, and all-cause mortality.
Table 4. Cox regression analyses of cardiovascular events, cardiovascular mortality, and all-cause mortality.
Cardiovascular EventsCardiovascular MortalityAll-Cause Mortality
Hazard Ratio
(95% CI)		p ValueHazard Ratio
(95% CI)		p ValueHazard Ratio
(95% CI)		p Value
Sex [male]0.685 (0.335–1.44)0.3051.73 (0.407–11.7)0.5001.00 (0.339–3.30)0.999
Age (years)1.03 (1.00–1.07)0.0381.02 (0.971–1.09)0.3961.04 (0.990–1.00)0.144
HD time (months)1.00 (0.994–1.01)0.6101.00 (0.983–1.01)0.9010.99 (0.984–1.01)0.909
Creatinine (mg/dL)0.726 (0.575–0.902)0.0050.517 (0.313–0.807)0.0060.577 (0.392–0.816)0.003
eGFR (min/mL/1.73 m2)1.04 (0.912–1.16)0.5681.25 (1.07–1.46)0.0031.20 (1.05–1.36)0.004
Kt/V0.560 (0.162–1.92)0.3560.888 (0.097–8.21)0.9160.629 (0.105–3.72)0.610
PTH (pg/mL)1.00 (1.00–1.00)0.3471.00 (0.999–1.00)0.4631.00 (0.999–1.00)0.711
Ca (mg/dL)1.27 (0.752–2.23)0.3892.24 (0.814–6.00)0.1191.62 (0.731–3.56)0.240
Pi (mg/dL)0.899 (0.715–1.13)0.3570.848 (0.544–1.29)0.4520.741 (0.512–1.05)0.101
IL-12p70 (pg/mL)0.987 (0.959–1.00)0.2300.994 (0.944–1.02)0.7120.989 (0.936–1.01)0.512
TNF (pg/mL)0.968 (0.882–1.00)0.3030.948 (0.699–1.01)0.5660.918 (0.680–1.01)0.415
IL-10 (pg/mL)1.01 (0.909–1.08)0.8821.04 (0.860–1.16)0.5791.01 (0.835–1.12)0.915
IL-6 (pg/mL)0.997 (0.985–1.00)0.3880.999 (0.978–1.00)0.7230.999 (0.982–1.00)0.681
IL-1β (pg/mL)0.976 (0.855–1.08)0.6770.956 (0.699–1.14)0.7080.884 (0.646–1.07)0.339
IL-8 (pg/mL)0.999 (0.995–1.00)0.2810.999 (0.995–1.00)0.5730.999 (0.996–1.00)0.505
α-Klotho (pg/mL)0.997 (0.983–1.01)0.6640.996 (0.964–1.02)0.7590.991 (0.960–1.01)0.438
Diabetes [yes]2.73 (1.31–6.11)0.0093.86 (0.900–26.7)0.1002.45 (0.802–9.10)0.138
The results in bold are statistically significant (p < 0.05).
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Lisowska, K.A.; Storoniak, H.; Soroczyńska-Cybula, M.; Maziewski, M.; Dębska-Ślizień, A. Serum Levels of α-Klotho, Inflammation-Related Cytokines, and Mortality in Hemodialysis Patients. J. Clin. Med. 2022, 11, 6518. https://doi.org/10.3390/jcm11216518

AMA Style

Lisowska KA, Storoniak H, Soroczyńska-Cybula M, Maziewski M, Dębska-Ślizień A. Serum Levels of α-Klotho, Inflammation-Related Cytokines, and Mortality in Hemodialysis Patients. Journal of Clinical Medicine. 2022; 11(21):6518. https://doi.org/10.3390/jcm11216518

Chicago/Turabian Style

Lisowska, Katarzyna Aleksandra, Hanna Storoniak, Monika Soroczyńska-Cybula, Mateusz Maziewski, and Alicja Dębska-Ślizień. 2022. "Serum Levels of α-Klotho, Inflammation-Related Cytokines, and Mortality in Hemodialysis Patients" Journal of Clinical Medicine 11, no. 21: 6518. https://doi.org/10.3390/jcm11216518

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop