The effect of Metformin and its combinations with other hypoglycemic agents on CRP blood levels

 

Marwa Mansour1*, Rana Makhous2

1Master Student, Department of Pharmacology and Toxicology, College of Pharmacy,

Tishreen University, Latakia, Syria.

2Professor in the Department of Pharmacology and Toxicology.

*Corresponding Author E-mail: marwa.mansour.1995@gmail.com, ranamakhous@gmail.com

 

ABSTRACT:

Background: C-reactive protein (CRP) is linked to inflammation and elevated cardiovascular risk in metabolic disorders. Metformin has been shown to lower CRP concentrations. However, it is still unclear whether elevated CRP levels could be modulated by metformin. Objective: This study aims to evaluate the effects of metformin and its combinations on CRP levels in T2DM patients. Patients and Methods: a prospective comparative study was carried out at Tishreen University Hospital and some private diabetic clinics in Lattakia, Syria during the period between April 2020 and March 2022.The study included three groups of patients: group I (31 patients, 32.6%) received metformin at a dose of 1,000mg/d, group II (30 patients, 31.6%) received modified release gliclazide (60mg/d) and group III (34 patients, 35.8%) received metformin with sitagliptin (50/1000mg/d). CRP levels were measured at baseline and after 3 months of treatment.  Results: a total of 95 patients, 55males (57.90%) and 40 females (42.1%) with a mean age of 50.72±6.6 years were included in the study. There were no significant differences between the three groups regarding age, sex, and BMI (p > 0.05). There was a significant decrease in FPG after treatment with metformin, gliclazide, and metformin with sitagliptin; 21.92%, 18.75%, and 24.39% respectively, p<0.0001. Metformin, gliclazide, and metformin with sitagliptin significantly reduced HbA1c by 18.7%, 17.36%, and 21.92% respectively. There was a significant change in CRP levels from baseline after receiving metformin (2.06±0.8 vs 3.46±0.9, p<0.001), and metformin with sitagliptin (1.84±0.6 vs 3.30±0.7, p:0<0001). However, the reduction in gliclazide group wasn’t significant (2.97±0.6 vs 3.14±1.1, p=0.09). Reduction in CRP levels wasn't influenced by age, sex or BMI, and was independent of glycemic control (p > 0.05). Conclusion: We demonstrated that metformin and its combination with sitagliptin have a favorable beneficial effect on inflammation marker CRP in patients with T2DM. 

 

KEYWORDS: Type 2 diabetes mellitus (T2DM), CRP, inflammation, Metformin, Gliclazide, Sitagliptin.

 

 


INTRODUCTION: 

Diabetes mellitus (DM) is a series of metabolic illnesses that cause hyperglycemia as a result of pathophysiologic changes, which included effective insulin secretion by pancreatic β cells and the inability of insulin-sensitive tissues to respond to insulin1.

 

Prevalence of DM has increased over the past decades. It is considered a worldwide epidemic with increased alterations in lifestyles and obesity incidence leading to premature morbidity and mortality2.

 

T2DM has been correlated with increased levels of inflammatory response. That might play an important role in T2DM, either by a causal relationship that leads to resistance to insulin, or by causing T2DM complications3.

 

Adipokines released from adipose tissue were shown to be associated with insulin resistance and Diabetes complications, through the stimulation of IL-6 and TNF-a, which in turn stimulate the production of acute phase proteins such as C-reactive protein, adhesion molecules, and other inflammatory molecules. This is considered to be the first step in the emergence of microvascular and macrovascular complications of diabetes mellitus.4,5,6

 

 

Several markers are used to assess the inflammatory state. However, the most important one is CRP, due to its uniformity and its long half-life. Additionally, increased levels of CRP have been shown to be correlated with a worse prognosis and increased cardiovascular risks in T2DM patients as follows: Low risk: CRP < 1.0mg/dL, moderate risk: CRP 1.0-3.0 mg/dL, High risk: CRP >3.0mg/dL.7,8,9

 

Adequate glycemic control is considered a necessary intervention to prevent or minimize the severity of chronic complications.Metformin, sulfonylureas, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, and sodium glucose cotransporter (SGLT2) inhibitors are types of drugs used to treat type 2 diabetes.10,11

 

When Metformin monotherapy fails to achieve an adequate degree of glycemic control, or in the case of Metformin intolerance, Sulfonylureas (SU), which are insulin secretagogues, are used as second-line therapy.This group includes Glyburide, Glipizide, Glimepiride, and Gliclazide which is the most SU prescribed in Syria.12

 

Metformin is a biguanide that is extracted from French lilac, a flower that was used as a herbal treatment in Europe in the early 1900s to help manage blood sugar.13 Since 1995, the FDA has approved it for the treatment of T2DM, and it is still the primary drug prescribed for T2DM patients, especially those who are overweight and have normal renal function.It works primarily by lowering the production of glucose in the liver and improving insulin sensitivity.

 

The anti-inflammatory properties of metformin may contribute therapeutic benefits beyond its activity to lower glucose. Studies have shown many other therapeutic effects of metformin including cardiovascular protection, weight reduction, polycystic ovary syndrome (PCOS), neuroprotective effect, nephroprotective effect, reducing risk of cancer, and benefic effects in tuberculosis.14,15,16,17

 

Different mechanisms were proposed to explain these effects of metformin, which may involve reducing the production of inflammatory cytokines (IL-1β, IL-6, TNF-α) through inhibition of NF-kB activation in macrophages.18,19

 

DPP4 inhibitors protect Endogenous glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) from proteolysis. The first drug in this group, Sitagliptin, was approved by the FDA in 2006; it is then followed by Vildagliptin, Saxagliptin, and Linagliptin.20 which were approved later. This study aimed to investigate changes in CRP levels during treatment with gliclazide and metformin each alone, or in combination with sitagliptin among T2DM patients.

 

Patientsand Methods:

This is a prospective comparative study of a group of T2DM patients attending Tishreen University Hospital and some private diabetic clinics in Latakia, Syria, during the period from April 2020 to March 2022.

 

Inclusion criteria included newly-recognized patients of Type II DM, males or females of all ages.The exclusion criteria were one presence of the following: chronic inflammatory disease, acute infection when specimen were collected, a history of trauma or surgery, allergic diseases, tumors, and patients who received anti-inflammatory drugs.

 

Patients participating in this study were divided, depending on antidiabetic agents, into three groups: Group I included 31 cases (32.6%) in which patients were given stable doses of metformin 1,000mg/d while Group II included 30 cases (31.6%) in which patients were given modified release gliclazide 60mg/d and Group III included 34 cases (35.8%) in which patients were given metformin together with sitagliptin 50/1000 mg/d.

 

Baseline measurements, included FBS, HbA1c, and CRP, were done before the study and repeated after 3 months of treatment using the same kits and analytical methods.

 

BMI was calculated according to the following equation: BMI = weight (kg)/[height (m)]2. Blood sample was taken after overnight fasting of 12hours. Sera were separated and measurements of CRP, FBS, and HbA1c were done. Glycated hemoglobin (HbA1c) was defined as good glycemic control if HbA1c <7% and as poor glycemic control if HbA1c>7.

 

Ethical approval:

All patients were provided complete and clear informed consent after a discussion about the purpose of the study. This study complies with the Declaration of Helsinki.

 

Statistical Analysis:

Statistical analysis was carried out with the use of IBM SPSS version 20. Basic descriptive statistics contained Standard deviations (SD), means, medians, frequencies, and percentages. When necessary, the Fisher exact test or the chi-square test was utilized to analyze the correlations and comparisons between the two groups. ANOVA was one of the methods used to contrast the associations between different groups. When comparing two paired groups, the Wilcoxon test was utilized At a 5% type I error rate (p0.05), all tests were deemed significant.

 

RESULT:

The study included a group of 95 patients (55male, 40 female) with T2DM. Age ranged from 35 to 65 years, with a mean age of 50.72±6.6 years. The baseline characteristics of patients were as shown in Table (1). No significant difference was found between the groups in terms of age, gender, and BMI (p>0.05). In group I, the mean age was 49.16±6.8 years, males represented 54.8% and females represented 45.2% of the patients with a mean value of BMI 34.23±4.02kg/m2. In group II, the mean age was 50.66±5.5 years, males represented 60% and females represented 40% of the patients, with a mean value of BMI 29.57±2.6 kg/m2. The mean age was 50.72±6.6 years, males represented 58.8% and females represented 41.2% of the patients, with a mean value of BMI 33.93±3.4kg/m2 in group III, but without significant difference between the three groups, p>0.05.

 

Table 2 presents the means of FPG, HbA1c, and CRP for each treatment group at baseline and after three months of the therapy. FPG was decreased by 21.92% with metformin treatment (136.03±24.3 versus174.22±19.5, p:0.0001), 18.75% with gliclazide (126.46±28.4 versus155.66±16.5, p:0.0001), and 24.39% with metformin and sitagliptin (149.88±22.9 versus 198.23±30.1, p:0.0001). Regarding HbA1c, it decreased with metformin by 18.71% (6.34±0.7 versus 7.80±0.7, p:0.0001), gliclazide by 17.36% (6.33±0.5 versus 7.66±0.4, p:0.0001), metformin and sitagliptin by 21.92% (6.34±0.9 versus 8.12±0.7, p:0.0001). CRP decreased compared to baseline with metformin by 40.46% (2.06±0.8 versus 3.46±0.9, p:0.001), with gliclazide by 5.4% (2.97±0.6 versus 3.14±1.1, p:0.09), and metformin with sitagliptin by 44.24% (1.84±0.6 versus 3.30±0.7, p:0.0001).

 

Table 1 Demographic characteristics of the study population by comparison of the groups

Group

 

Variables

Group I

Group II

Group III

P value

Metformin

(n=31)

Gliclazide

(n=30)

Metformin+ Sitagliptin

(n=34)

 

Age     (years)

49.16±6.8

50.66±5.5

50.72±6.6

0.1

Sex

Male

17(54.8%)

18(60%)

20(58.8%)

0.2

Female

14(45.2%)

12(40%)

14(41.2%)

BMI (kg/m2)

34.23±

4.02

29.57±

2.6

33.93±

3.4

0.09

 

The relations between changes in CRP and the parameters analyzed in the different groups of therapy of the study group are summarized in table 3. There were no significant differences between changes in the levels of CRP according to age, gender, BMI, and glycemic control in the different groups of treatment (p>0.05).


 

Table 2: Comparison of measurements between baseline and at 3 months after treatment with various treatments

Type of Therapy Variables

Metformin + Sitagliptin

(50/1000 mg/d)

Gliclazide

(60 mg/d)

Metformin

(1,000 mg/d)

P value

FPG (mg/dL)

Baseline

174.22±19.5

155.66±16.5

198.23±30.1

 

0.0001

 

0.001

After 3 months

136.03±24.3

126.46±28.4

149.88±22.9

P value

0.0001

0.0001

0.0001

Change rate

-21.92%

-18.75%

-24.39%

HbA1c (%)

Baseline

7.80±0.7

7.66±0.4

8.12±0.7

 

0.09

 

0.8

After 3 months

6.34±0.7

6.33±0.5

6.34±0.9

P value

0.0001

0.0001

0.0001

Change rate

-18.71%

-17.36%

-21.92%

CRP (mg/dL)

Baseline

3.46±0.9

3.14±1.1

3.30±0.7

 

0.4

 

0.001

After 3 months

2.06±0.8

2.97±0.6

1.84±0.6

P value

0.001

0.09

0.0001

Change rate

-40.46%

-5.4%

-44.24%

 

Table 3: Comparison of change of CRP levels after treatment with various treatments according to demographic variables

Type of Therapy

Variables

Metformin (1,000 mg/d)

Gliclazide (60 mg/d)

Metformin+Sitagliptin

(50/1000 mg/d)

N

ΔCRP

N

ΔCRP

N

ΔCRP

Age group (years)

 

20-29

-

-

-

-

-

-

30-39

4

1.1

1

0.18

2

0.6

40-49

11

1.6

13

0.13

10

1.8

50-59

13

1.4

14

0.21

19

1.36

60-69

3

1.5

2

0.3

3

1.63

>70

-

-

-

-

-

-

P value

        0.5

       0.9

       0.8

Sex

 

Male

17

1.3

18

0.17

20

1.5

Female

14

1.4

12

0.18

14

1.4

P value

   0.1

     0.6

       0.1

BMI

(kg/m2)

Underweight

(Below 18.5)

-

-

-

-

-

-

Normal

(18.5-24.9)

-

-

-

-

-

-

Overweight

(25.0-29.9)

5

1.4

12

0.16

4

1.1

Obese

(30.0-34.9)

12

1.5

15

0.20

19

1.3

Severe obesity

(35 and above)

14

1.3

3

0.06

11

1.6

P value

0.2

0.7

        0.1

Glycemic control

Controlled

20

1.48

21

0.2

24

1.48

Uncontrolled

11

1.39

9

0.05

10

1.43

P value

0.1

0.09

       0.2

 


DISCUSSION:

The principal clinical concern of T2DM is one of the most complicated diseases with high rate of morbidity and mortality. Treatment with agents that have potential anti-inflammatory effects is important to improve the final outcome due to the role of chronic inflammation in insulin resistance and Diabetes complications. The result of the current study revealed that there was a decrease in C-reactive protein levels in the three groups, but this decrease was significant only in metformin alone and in its combination with sitagliptin groups (p<0.05).

 

These results are consistent with what Gamit et al. (2014)  reached in a study conducted on 30 T2DM patients with a mean age of 50.03±10.03 years who received treatment with metformin and there was a significant decrease in FPG and CRP levels after 3 months of therapy21, also Selvi et al. (2021) showed in a study conducted on 50 T2DM patients with a mean age of 40±4.3 years who received treatment with metformin a significant decrease in FPG, HbA1c, and CRP levels after 6 months of the treatment22.

 

Yalan WEIet al. also found that metformin in combination with sitagliptin has decreased CRP levels after 8 weeks of treatment23.

 

Hasani et al. (2021) demonstrated in a multicenter study trial conducted on 1776 patients with T2DM that CRP levels decreased significantly after treatment with metformin (p:0.03), especially in patients whose duration of therapy was longer than 24 weeks24.

 

In contrast to our study, Abdulkadir et al. (2012) showed in a study conducted on 53 patients who received metformin and 50 patients treated with glibenclamide during two months of follow-up that CRP levels didn't significantly change after treatment in both groups (p>0.05)25. However, this difference in results may be due to the difference in the duration of the study, which lasted for only eight weeks.

 

The comparison of the metformin and gliclazide groups showed that there was a significant decrease in FPG, and HbA1c in both groups but only the metformin group had a significant decrease in CRP levels which indicates that metformin may have an anti-inflammatory effect independent of its hypoglycemic effect.

 

Some studies have indicated the presence of anti-inflammatory activity of metformin, and it has been suggested that the mechanism behind this activity is due to the activation of AMPK, which leads to inhibition of NF-Κb and a decrease in the production of inflammatory cytokines including IL-6, and this ultimately leads to a decrease in CRP levels26,27.

 

However, the reduction of CRP levels was the highest in the metformin together with sitagliptin group, and this could be a result of treatment with metformin as shown in Group I or could be a result of both metformin and sitagliptin. Some studies indicated an anti-inflammatory effect of sitagliptin which is by inhibiting inflammatory signaling mechanisms and that is by down-regulating the expression of CD26, toll-like receptor (TLR-2 &TLR-R), mitogen-activated protein kinase (MAPK-8), chemokine receptor 2(CCR-2), nuclear factor Kappa-B kinase and TNF-α on mononuclear cells28.

 

CONCLUSION:

Both metformin and metformin with sitagliptin have a favorable effect on both glucose blood levels and CRP blood levels which could improve outcomes and reduce the risk of cardiovascular diseases and other diabetes complications.

 

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Received on 24.02.2023            Modified on 28.03.2023

Accepted on 18.05.2023           © RJPT All right reserved

Research J. Pharm. and Tech 2023; 16(10):4602-4606.

DOI: 10.52711/0974-360X.2023.00749