Evaluation of Serum Cholinesterase Level as A diagnostic Marker in Chronic Liver Disease

INTRODUCTION

Liver disorders are the major leading cause of morbidity and mortality worldwide. Biochemical tests for the assessment of liver function (commonly referred to as liver function tests) includes measurement of serum total bilirubin, serum aspartate and alanine transaminases serum alkaline phosphatase, serum protein and albumin (Kumar and Keerthana, 2016).

Liver function tests are raised in non-liver diseases, e.g. transaminase levels in heart diseases, alkaline phosphatase levels in bone diseases etc. So, there is a need for a test which should be more specific, and sensitive for diagnosis of liver disease) Chowdhryand Kaushik, 2017).

Cholinesterase is a family of enzymes that catalyze the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, an essential process for the restoration of the cholinergic neurotransmission (Gülçin et al., 2016).

There are two types of cholinesterases, acetylcholinesterase (AChE) or erythrocyte cholinesterase, which is most concentrated in the central nervous system, striated muscle and erythrocyte membrane, and butyrylcholinesterase (BChE) or plasma cholinesterase, which is most abundant in plasma (Fonseca et al., 2020).

Cholinestrase has a serum half-life between 8 and 12 days(Amin et al., 2017).

Cholinesterase is synthesized mainly in
hepatocytes and released into the blood. Cholinesterase activity is reduced in liver dysfunction due to reduced synthesis. The predominant hepatic source of serum cholinesterase, the marked decrease in its synthesis with hepatocyte dysfunction and restoration of synthesis with hepatocyte recovery suggests that serum cholinesterase activity might be a more specific indicator of liver dysfunction than the traditional liver function test (Roshankumar et al., 2019).

This study was performed to evaluate serum cholinesterase levels in chronic liver disease patients.

SUBJECTS AND METHODS

       This study was done at Al-Azhar University Hospitals during the period between June 2018 and August 2020 on a total of 80 individuals (age and sex matched). Those individuals were divided into 2 groups: group1 (60 patients) and group 2 (20 control). The patients group was subdivided into two equal subgroups: Group 1(A) and Group 1(B) hepatic disease subjects. Control group were apparently healthy individuals.

Inclusion criteria: Patients presented with cirrhotic liver disease and non-cirrhotic hepatic disease aged between 40-65 years.

Exclusion criteria: Patients with congenital liver disorder, chronic malnutrition, organophosphorus poisoning, muscular dystrophy and pregnancy.

Methods:

I. Full history taking and clinical examination.

II. Sample Collection: Ten ml venous blood was withdrawn from all participants of the study (both patients and controls) ; 2ml on EDTA for routine CBC which was done using Sysmex Kx-21 automated cell counter, 2ml on Na citrate for Prothrombin time and the remaining amount in plain tube was left for clotting, and then centrifuged. Separated serum was divided in 2 aliquots, one for routine biochemical tests performed by an enzymatic colorimetric reaction using a Modular P analyzer(Roche Diagnostics) while the other aliquot was stored deeply frozen at - 20°C for estimation of serum cholinesterase.

Serum Cholinesterase was done using a Biolis 50i Superior analyzer by a colorimetric kinetic assay method using a commercially available kit supplied by BEN – BIOCHEMICAL ENTERPRISE, Milano, Italy.

Statistical analysis:

          Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 2, IBM Corp. U.S.A. Quantitative data were expressed as mean ± standard deviation (SD). Qualitative data were expressed as frequency and percentage. P-value ≤ 0.05 was considered significant.

For all analyses, Chi-squared (X2) test, Fisher's exact test, one way ANOVA test and Kruskal Wallis test were used.

RESULTS

Our study included a total of 80 individuals. 60 patients recruited to Al-Azhar university hospitals and 20 apparently healthy individuals.

         Table (1) showed the demographic characteristics of study population in control and Chronic Liver Disease patients:

• Statistically significant difference (p-value < 0.05) between studied groups as regard ALP.
• Statistical significant difference (p-value < 0.001) between studied groups as regard ALT, AST, Albmin, Bilirubin (T & C), PT & INR.
• Statistical significant difference (p-value < 0.001) between studied groups as regard TLC, PLTs & Hb.

• No statistical significant difference (p-value > 0.05) between studied groups as regard HBs Ag.

• Statistically significant difference (p-value < 0.05) between studied groups as regard HCV Ab.
• Statistically significant difference (p-value < 0.05) between studied groups as regard AFP.
• Highly statistical significant difference (p-value < 0.001) between studied groups as regard Cholinesterase.

DISCUSSION

           This study showed that Serum Cholinesterase level markedly decreased in patients with liver cirrhosis followed by patients with chronic hepatitis when compared with controls. The difference in the mean was highly statistically significant.

The results of this study were matched with that of Chowdhry (2014) who found that serum cholinesterase levels were found to be significantly decreased in majority of cases of liver disease. Mean serum cholinesterase level was very much lowered in cirrhosis patients as compared to other liver diseases.

Also, this study was consistent with the study done by Abbas and Abbas (2017) who found that mean serum cholinesterase decreased with reduced hepatic reserves. Cholinesterase levels predict survival in patients with parenchymal cirrhosis, distinguish between liver disease and non-liver disease aberration in liver function tests and differentiate cirrhosis from non-cirrhosis.

However, Dhungana (2014) found that butyrylcholinesterase (BChE) level markedly decreased in carcinoma of liver followed by cirrhosis of liver, infective hepatitis, obstructive jaundice when compared with controls. The difference in the mean was statistically significant. Regarding liver diseases, a decreased BChE activity reflects hepatocellular impairment; similarly, recovery was evidenced by a gradual increase of BChE levels.

However, Gokani et al. (2014) found that, the difference between the mean serum cholinesterase activity of liver diseases and control group was statistically significant with 90% sensitivity and 100% specificity, suggesting that reduced serum cholinesterase activity strongly indicate liver dysfunctions. Morever, Ramachandran et al. (2015) found that median serum ChE in cirrhotics was 1590 IU/L compared to controls 7886 IU/L, pMeng et al. (2013) showed that the level of cholinesterase is closely correlated with the damage severity of liver cells and may respond to the liver reserve function of cirrhotic patients.

        CONCLUSION: There is a strong relationship between lower level of serum cholinesterase  in patients with more advanced disease, indicating that reduced serum  cholinesterase  level is most likely the result of reduced of synthesis from hepatocytes. Cholinesterase can be used as a routine diagnostic test besides other liver function tests for investigation of liver disorders and a prognostic parameter in patients with liver cirrhosis.  

      ACKNOWLEDGEMENT 

           We would like to thank the Clinical
Pathology Department and Internal Medicine
Department of Al-Azhar Faculty of Medicine.
We are also indebted to all the patients and our
colleagues for their co-operation in this research.

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