Investigation of serum TNF-Alpha and IL-6 concentrations in patients with long term hemodialysis

Objectives: To investigate serum TNF-α and IL-6 concentration in long-term hemodialysis patients (LHD) and find out the association between serum TNF-α and IL-6 concentration and some characteristics of LHD patients.

INVESTIGATION OF SERUM TNF-ALPHA AND IL-6

CONCENTRATIONS IN PATIENTS WITH LONG-TERM

HEMODIALYSIS

Nguyen Duc Loc*; Ha Hoang Kiem**; Vu Xuan Nghia***

SUMMRAY

Objectives: To investigate serum TNF-α and IL-6 concentration in long-term hemodialysis patients (LHD) and find out the association between serum TNF-α and IL-6 concentration and some characteristics of LHD patients Subjects and methods: A prospective, cross-sectional study in 107 LHD patients who treated at Hemodialysis Department, An Sinh Hospital from

2 - 2014 to 2 - 2017 and a control group of 51 healthy people Urinary NGAL concentration had been measured in all 116 patients and healthy people Results: TNF-α and IL-6 concentrations

in study group were significantly higher than those in the control group with p < 0.001 33.6% of patients had an increase in both TNF-α and IL-6 concentrations This proportion was 31.8% for single increase in TNF-α and 10.3% for single increase in IL-6 concentration IL-6 concentration had a positive correlation with hemodialysis duration (r = 0.46; p < 0.001) Mean value of TNF-α concentration in patients with hepatitis virus infection was significantly higher than those without infection with p < 0.05, while IL-6 concentration was significantly higher in preserved urine output patients compared with non-preserved urine output patients (p < 0.001) Elevated proportion of IL-6 concentration was significant higher in decreased albumin group compared with no change group (62.5% versus 38.6%) with p < 0.05 Conclusion: TNF-α and IL-6 concentrations were elevated in LHD patients TNF-α, and IL-6 concentrations had strong relation with hemodialysis duration, hepatitis virus infection, preserved urine output and decreased albumin status in those patients

* Keywords: Long-term hemodialysis; TNF-α; IL-6

INTRODUCTION

Chronic inflammation is one of the

characteristics of LHD patients, which has

been shown to be a strong predictor of

morbidity and mortality in this population

Patients with chronic renal failure commonly

present with abnormalities of immune

function strictly correlated with abnormalities

of immune cell reactivity, phenotype

alterations of receptors and altered

expression of cell surface receptors These abnormalities are caused by impaired excretory function of kidney and the accumulation of uremic toxins in addition

to bioincompatibility of dialyzer membranes The increased levels of specific cytokines such as Interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) or acute phase proteins (C-reactive protein) have been found to be associated with cardiovascular disease (CVD) in LHD patients

* An Sinh Hospital

** 103 Military Hospital

*** Military Medical University

Corresponding author: Nguyen Duc Loc (ducloc09@yahoo.com)

Date received: 02/12/2017 Date accepted: 23/01/2018

IL-6 and high-sensitivity C-reactive

protein (hs-CRP) are two inflammatory

markers or mediators which are prone to

an increased serum level in end-stage

renal disease (ESRD), infections,

cerebrovascular accidents, myocardial

infarction, malignancies, and rheumatic

diseases TNF-α is a pro-inflammatory

cytokine, but mediates both other

pro-inflammatory and anti-inflammatory

cytokines TNF-α has regulatory effect on

plasminogen activator inhibitor (PAI-1)

expression and secretion by vessel

endothelial cells, the main fibrinolysis

inhibitor elevated level of TNF-αassociated

with an increased risk for vascular

diseases TNF-α in a variety of diseases

has been reported, and TNF-α causes

hypertrophy as well as negative inotropic

effects on cardiac myocytes Circulating

TNF-α concentrations is reported elevated

in end-stage renal disease patients

undergoing LHD Therefore, according to

the important roles of above factors, we

conducted this research for the aim:

- Investigate serum TNF-α and IL-6

concentration in patients with chronic

kidney disease undergoing LHD

- Find out the association of serum

TNF-α and IL-6 concentration with some

clinical characteristics of LHD patients:

hemodialysis duration, oliguric state, albumin

concentration, and hepatitis virus infection

SUBJECTS AND METHODS

1 Subjects

The study was conducted with a group

of 107 LHD patients at Hemodialysis

Department, An Sinh Hospital from 2 -

2014 to 2 - 2017 and a control group of

31 healthy people

* Inclusion criteria:

- Patients with LHD

- Hemodialysis duration ≥ 3 months

- Causes of chronic renal failure include: chronic glomerulonephritis, chronic pyelonephritis, hypertension and diabetes

- Patient's age ≥ 18

- Patients are being filtered with low ultrafiltration coefficient

- Agree to participate in research

* Exclusion criteria:

- Severe heart or liver failure

- End-stage cancer

- Having acute diseases such as: bacterial infections, myocardial infarction, acute heart failure, cerebral stroke

- Difficulties in the implementation of intravascular pathway

- Patients with conditions requiring special filtration such as acute pulmonary edema, hyperkalemia

- Having surgery within 1 month

2 Methods

* Study design: A prospective,

cross-sectional descriptive study

* Steps of study:

- Ask for medical history and some main clinical symptoms

- Clinical examination and routine laboratory tests

- Have some basic treatment

- LHD using 2 different methods

- Quantification of serum TNF-α and IL-6 levels (before and after intervention)

- Collect and process data according to statistical algorithm

* Statistical analysis: Using SPSS 17

for window and Epical 2,000 software

RESULTS AND DISCUSSIONS

1 Serum TNF-α and IL-6 concentration in study group

Table 1: Comparing serum TNF-α and IL-6 concentration between study group and

control group

TNF-α

(ng/L)

IL-6

(ng/L)

TNF-α and IL-6 levels in study group were significantly higher than in the control group with p < 0.001

Table 2: Changes of TNF-α and IL-6 levels in study group (n = 107)

TNF-α (ng/L)

IL-6 (ng/L)

- The percentage of patients with increased TNF-α and IL-6 concentration were 65.4% and 43.9%, respectively

- There were no patients with decreased TNF-α and IL-6 concentration

Chart 1: Percentage of TNF-α and IL-6 levels in study group

We found that 33.6% of patients had increased in both TNF-α and IL-6 concentrations The proportion of single increase of TNF-α concentration was 3.1 times higher than that in IL-6 concentration

TNF-α

Increased IL-6 No change IL-6

%

80

70

60

50

40

30

20

10

0

2 Relation between TNF-α and IL-6 concentrations and some characteristics

of patients

Table 3: Relation between TNF-α and IL-6 concentrations and hemodialysis duration

(n = 107)

- Mean value of TNF-α concentration in study group were different in each

hemodialysis duration groups However, it was not significant difference with p > 0.05

- Mean value of IL-6 concentration increased with time of dialysis There was a

statistically significant association between IL-6 concentration and dialysis duration (p < 0.005)

Table 4: Correlation between TNF-α and IL-6 concentrations and hemodialysis

duration (n = 107)

Hemodialysis duration Indexes

- IL-6 concentration had a proportional correlation with hemodialysis duration (r =

0.46; p < 0.001)

- There was no correlation between TNF-α and hemodialysis duration (r = 0.15; p = 0.13)

Table 5: Relation between TNF-α and IL-6 concentrations and hepatitis virus infection

(n = 107)

Status

Elevated proportion

n (%)

- Mean value of TNF-α concentration in patients with hepatitis virus infection was

significantly higher than that in whom without infection with p < 0.05

- There was no relation between IL-6 concentration and hepatitis virus infection status in study group (p > 0.05)

Table 6: Relation between TNF-α and IL-6 concentration and preserved urine output

status (n = 107)

- TNF-α concentration was different between preserved urine output and non-preserved urine output patients, but this difference was not significant with p > 0.05

- IL-6 concentration was significantly higher in preserved urine output patients compared with non-preserved urine output patients (p < 0.001)

Table 7: Relation between TNF-α and IL-6 concentrations and serum albumin

concentration (n = 107)

Elevated proportion

n (%) Decreasing albumin < 35

- Mean value of TNF-α and IL-6 concentration were higher in decreased albumin group compared with non-decreased group, but it was not significantly different with

p > 0.05

- Elevated proportion of IL-6 concentration was significantly higher in decreased albumin group compared with non-decreased group (62.5% versus 38.6%) with p < 0.05

DISCUSSION

Chronic inflammation is high prevalent

in LHD patients, which is a strong

independent predictor of all causes and

CVD mortality in those population [4] It

may explain the excess CVD risk in LHD

patients, in whom inflammation is common Certain pro-inflammatory cytokines, such

as IL-6 and TNF-a, are considered as early drivers of the inflammatory response When comparing the study group and control group we found that TNF-α, and

IL-6 levels in study group was significantly

higher than those in the control group

(p < 0.001) The percentage of patients

with increased TNF-α and IL-6 concentration

were 65.4% and 43.9%, respectively Our

results also pointed out that 33.6% of

patients had increased in both TNF-α and

IL-6 concentration, 31.8% of patients had

increased of single TNF-α and this

percentage in IL-6 was 10.3% There

were no patients with decreased TNF-α

and IL-6 concentration Our results are in

good agreement with data publised

previously: Babaei M [1], Cao H [2] and

Jin K et al [5]

In our study, mean value of IL-6

concentration significantly increased

with hemodialysis duration (p < 0.005)

Apparently, dialysis time was associated

with IL-6 rather than TNF-α A number of

studies in the world have suggested that

the progression of fibrosis and atherosclerosis

increases with time of dialysis [7, 9] If

TNF-α is usually associated with acute

inflammation (particularly secreted by

macrophages, necrotic cells), IL-6 is

associated with chronic inflammation and

atherosclerosis That is why IL-6 is related

to the dialysis time

Our results also pointed out that mean

value of TNF-α concentration in patients

with hepatitis virus infection was significantly

higher than those without infection with

p < 0.05, while there was no relation

between IL-6 concentration and hepatitis

virus infection status in study group with

p > 0.05 Although the reasons leading to

hepatitis virus infection have not been

fully clearly understood yet, more and more evidences showed that cytokines obviously play important roles in perpetuating the chronic inflammatory state TNF-α and TNF-β were also important mediators in the antiviral response In addition, data from related studies had been showed that the patients had contamination with virus, and increased of T-cell response (such as TNF-α production), which correlated with the result of hepatitis virus infection There are significant differences

in the ability to produce cytokines among individuals [3]

Residual kidney function (RKF), even

at the low glomerular filtration rate (GFR) levels in dialysis patients plays a crucial role in clearance of uremic toxins, prevents volume overload and its sequelae, such

as left ventricular hypertrophy (LVH) and congestive heart failure (CHF), and is associated with improved metabolic parameters In our study, IL-6 concentration was significantly higher in preserved urine output patients compared with non-preserved urine output patients (p < 0.001) Research by Shafi T et al (2010) also showed a significant association between IL-6 and renal function in hemodialysis patients [10] Inflammation

is a common problem in hemodialysis patients, the increased of serum CRP and IL-6 levels directly affect the cardiovascular events and survival of hemodialysis patients There had been reports about the relation between residual kidney function and pre-inflammatory cytokine levels in dialysis patients [8]

Studying the relation between TNF-α

and IL-6 concentration and serum albumin

concentration, we realized that percentage

of patients with elevated IL-6 level was

significantly higher in decreased albumin

group compared with non-decreased group

(62.5% versus 38.6%) with p < 0.05 Kim

Y et al (2013) [6] also showed that IL-6

level was significantly correlated with serum

albumin concentrations in hemodialysis

patients Serum albumin levels decrease

with inflammation due to several causes,

including reduced synthesis, increased

catabolism, and translocation of albumin

to extravascular pools TNF-α and IL-1

directly suppress appetite Cytokines may

also induce catabolism, leading to a

wasting illness that is indistinguishable

from prolonged starvation

CONCLUSIONS

* Serum TNF-α, and IL-6 concentration

in study group:

- TNF-α, and IL-6 level in study group

was significantly higher than those in the

control group with p < 0.001

- The percentage of patients with

increased TNF-α and IL-6 concentration

were 65.4% and 43.9%, respectively

33.6% of patients had an increase in both

TNF-α and IL-6 concentration

* Relation between TNF-α and IL-6

concentration and some characteristics of

patients:

- Mean value of IL-6 concentration

increased with time of dialysis There was

a statistically significant association between

IL-6 concentration and dialysis duration

(p < 0.005) IL-6 concentration had a proportional correlation with hemodialysis duration (r = 0.46; p < 0.001)

- Mean value of TNF-α concentration in patients with hepatitis virus infection was significantly higher than those without infection with p < 0.05 There was no relation between IL-6 concentration and hepatitis virus infection status in study group (p > 0.05)

- IL-6 concentration was significantly higher in preserved urine output patients compare with non-preserved urine output patients (p < 0.001)

- Elevated proportion of IL-6 concentration was significantly higher in decreased albumin group compared with non-decreased group (62.5% versus 38.6%) with p < 0.05

REFFERENCES

1 Babaei M et al Evaluation of plasma

concentrations of homocysteine, IL-6, TNF-alpha, hs-CRP, and total antioxidant capacity

in patients with end-stage renal failure Acta Med Iran 2014, 52 (12), pp 893-838

2 Cao H et al Circulatory mitochondrial

DNA is a pro-inflammatory agent in maintenance hemodialysis patients PLoS One 2014, 9 (12), p e113179

3 He J et al The relationship between

tumor necrosis factor-alpha polymorphisms and hepatitis C virus infection: a systematic review and meta-analysis Ren Fail 2011, 33 (9), pp.915-922

4 Hung A et al Determinants of C-reactive

protein in chronic hemodialysis patients: relevance of dialysis catheter utilization Hemodial Int 2008, 12 (2), pp.236-243

5 Jin K, N.D.Vaziri Elevated plasma

cyclophillin A in hemodialysis and peritoneal

dialysis patients: a novel link to systemic

inflammation Iran J Kidney Dis 2017, 11 (1),

pp.44-49

6 Kim Y et al Relative contributions of

inflammation and inadequate protein intake to

hypoalbuminemia in patients on maintenance

hemodialysis Int Urol Nephrol 2013, 45 (1),

pp.215-227

7 Lee C.T, et al Biomarkers associated

with vascular and valvular calcification in

chronic hemodialysis patients Dis Markers

2013, 34 (4), pp.229-235

8 Pecoits-Filho R et al Associations

between circulating inflammatory markers and residual renal function in CRF patients Am J Kidney Dis 2003, 41 (6), pp.1212-1218

9 Pencak P et al Calcification of coronary

arteries and abdominal aorta in relation

to traditional and novel risk factors of atherosclerosis in hemodialysis patients BMC Nephrol 2013, 14, p.10

10 Shafi T et al Association of residual

urine output with mortality, quality of life, and inflammation in incident hemodialysis patients: the choices for healthy outcomes in caring for end-stage renal disease (CHOICE) study Am

J Kidney Dis 2010, 56 (2), pp.348-358