Study of Serum Adenosine Deaminase Level in Type 2 Diabetes Mellitus and its Correlation with Glycemic Control

Diabetes mellitus is a cluster of abnormal metabolic disorder having common features of hyperglycaemia with a state of increased free radical activity. Chronic hyperglycemic status favours auto-oxidation and the formation of advanced glycation end products. Adenosine deaminase (ADA) is considered as a good marker of cell mediated immunity. Increased ADA activity in diabetic individuals could be due to altered insulin related T-lymphocyte function. Hyperglycaemia is associated with increased level of (ADA), which is one of the factor which leads to increase oxidative stress level by generatingthe reactve oxygen species (ROS) leading to insulin resistance. In our study, ADA level was significantly high in controlled diabetes mellitus type 2 (group II with HbA1c < 7) and was much higher in uncontrolled diabetics (group III with HbA1c > 7) compared to healthy controls (group I). The present study was aimed to find the level of Serum (ADA) among the patients with type 2 diabetes mellitus through a case control study and correlation of Adenosine deaminase with glycemic control (HbA1c). Comparison of the parameters fasting plasma glucose (FPG), post prandial plasma glucose (PPPG) HbA1c, and ADA between the 3 groups were done using Student t test and was statistically significant. Pearson’s coefficient correlation was done between ADA and HbA1c and a positive correlaion was seen that was also statistically significant. Original Research Article Hemalatha et al.; JPRI, 33(23A): 39-49, 2021; Article no.JPRI.66789 40 This indicates that ADA ses with the extent of severity of type 2 diabetes. Positive correlation of ADA with HbA1c provides the information that ADA can be considered to reflect the glycemic status of the individual.


INTRODUCTION
Diabetes mellitus (DM) is a chronic endocrine metabolic disorder but largely preventable non communicable disease which is responsible for millions of deaths annually, debilitating complications, and incalculable human misery. It consistently demonstrates three cardinal abnormalities namely, resistance to the action of insulin in peripheral tissues particularly muscle and adipose tissue, decreased insulin secretion and increased glucose production by the liver. Insulin resistance is decreased biological response to normal concentrations of circulating insulin. It plays a central role in pathophysiology of type 2 Diabetes. Diabetes mellitus is associated with oxidative stress which occurs as a result of imbalance between pro-oxidants and antioxidants [1][2][3]. Assessing glycemia in diabetes has always been a challenge. Monitoring glycemic control is an essential component of diabetic care [4]. Complications occurrence is linked to the accumulation of glycation adducts in tissue proteins, any analytical method that serves as an index of the extent of glycation should clearly be used to guide therapy in diabetes. The core of the issue is glycemic control. Amongst the various markers of glycemic control, glycated hemoglobin has now been established as the most reliable [5].
Immunological disturbances in type 2 diabetic individuals have an association with cell mediated responses [6] and inappropriate Tlymphocyte function, which is vital in diabetes and has a link with insulin defect [7]. Adenosine deaminase, an enzyme distributed in the human tissues, was considered as good marker of cell mediated immunity [8]. It plays a crucial role in lymphocyte proliferation and differentiation [9] and shows its highest activity in T-lymphocytes [10].
Adenosine deaminase (ADA) is an enzyme of purine metabolism. It acts on adenosine and other adenosine nucleoside analogues and catalyze its hydrolytic cleavage into inosine and ammonia. It is a cytosolic enzyme, which has been the object of considerable interest. Adenosine mimics the action of insulin on glucose and lipid metabolism in adipose tissue and the myocardium. Adenosine modulates the action of insulin on various tissues differently. Concentration of Adenosine in tissues is affected by ADA level [11].
Adenosine deaminase has been previously reported to be a marker for insulin function [12,13]. But its connection with the immune system was not yet established in the patients with diabetes mellitus type 2. Even though there are some reports available on adenosine deaminase levels in the patients with diabetes mellitus type 2, these are all inconclusive and controversial [12]. Since a relationship exists between adenosine deaminase and cell mediated immunity [14], we have undertaken this study to determine its activity in serum (what do you mean?) and understand its importance in the immunopathogenesis of type 2 diabetes mellitus.

MATERIALS AND METHODS
The study was conducted in a sample of 60 patients with diabetes type 2 attending diabetic outpatient department and 40 healthy nondiabetic individuals who came for routine checkup at Sree Balaji Medical College & Hospital.

Study Individuals were divided into 3 Groups
• Group I comprised of 40 healthy individuals both males and females in the age group of 30 -60 years from the general population who volunteered for getting included in the present study.

following overnight
Collection drawn from each vacutainer system prandial (2 hour) vacutainer for PPBS within half an hour analysis was done.

RESULTS AND DISCUSSION
The study population comprised of individuals, of which 60 were Diabetic were healthy controls. All the study were in the age group between 30 and individuals in control group sex matched with diabetic cases.
Of this 60 Diabetic individuals, one group II belonging to have the HbA1c and the other half were in group III have HbA1c > 7.  The levels in diabetics are higher controls and the difference is strongly (P< 0.02).      .672(**) 0.000 All these data are shown in the tables above. Do not repeat! HbA1cHbA1cHbA1cAll these data are shown in the tables above. Do not repeat! Adenosine deaminase (ADA) acts on adenosine and several other adenosine nucleoside analogues. Increased adenosine activity mimics the activity of insulin on glucose and lipid metabolism in adipose tissue [15]. Also, ADA is considered to be a marker of T cell activation and a producer of reactive oxygen species (ROS) [16]. Immunological disturbances in type 2 diabetic individuals have an association with cell mediated responses and inappropriate Tlymphocyte function, which is vital in this pathogenic condition, has a link with insulin defect [17].

Mechanism of ADA Causing Insulin Resistance
Adenosine modulates insulin action on various tissues differently and its concentration in tissues is affected by ADA levels. Adenosine potentiated insulin and contraction stimulated glucose transport in skeletal muscles by enhancing the increase in GLUT-4 at the cell surface. This raised the possibility that decreased adenosine production or action due to raised ADA could play a causative role in insulin resistance. [18]. Adenosine exerts a protective role by inhibiting lipolysis. ADA inactivate adenosine, hence activates lipolysis causing increased cAMP levels. This elevation of free fatty acids causing dysregulated fat metabolism leads to further subsequent development of type 2 Diabetes [19]. Various studies Who? show altered Adenosine deaminase level in type 2 DM. Most of them showed increased adenosine deaminase activity in type 2 diabetes mellitus patients [20][21]. have shown increased level of serum ADA activity in type 2 DM patients and its correlation with HbA1c and suggested that ADA is an important enzyme for modulating the bioactivity of insulin [22]. Also suggest that ADA play important role in insulin effect and glycemic control. Increased activity of ADA might be marker for insulin. Hoshino et al also suggested that mean serum level of ADA1 and ADA2 level is high in NIDDM (noninsulin dependent diabetes mellitus) and IDDM (Insulin dependent diabetes mellitus) than healthy donor (higher in NIDDM than IDDM). ADA2 activity in the poorly controlled NIDDM patients directly correlated with the HbA1c level.
The significant increase in adenosine deaminase activity in diabetic subjects tend to be found for having altered the immunity in animals [23]. Therefore, ADA may serve as an immunoenzyme marker in the aetiopathology of type 2 DM 11 .. Our study data also coincided with the previous literatures and estimates that Adenosine deaminase (ADA) levels was significantly high in type II diabetics than healthy controls .

CONCLUSION
This study results clearly shows that Adenosine deaminase (ADA) levels are increased in type 2 diabetics and positive correlation of ADA with glycemic control conveys that ADA may serve as a prognostic factor in type II diabetes mellitus. ADA, being an important enzyme for modulating the bioactivity of insulin and its essential role in the effect of insulin and glycemic control, it may also serve as a tool in assessing the extent of oxidative stress. All these features of ADA provides evidence to suggest ADA as a glycemic marker of type II diabetes. Hence, by analysing ADA levels in diabetics, glycemic control and insulin resistance can be assessed. Raised ADA levels can be an early indicator of progressive diabetic change insisting to initiate supportive therapy and preventive measures for the development of diabetic complication and thereby improving the outcome of the disease.

CONSENT AND ETHICAL APPROVAL
The research and ethical committee of the university approved the study protocol. All participants were provided with written informed consent before enrolment in the study.