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ORIGINAL ARTICLE
Year : 2018  |  Volume : 14  |  Issue : 9  |  Page : 480-485

Imbalance of T-helper 1/T-helper 2 cytokines and impaired glucose tolerance among patient with acute coronary syndrome


Department of Endocrinology, Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China

Date of Web Publication29-Jun-2018

Correspondence Address:
Zhao-Hui Mo
Department of Endocrinology, Third Xiangya Hospital, Central South University, 138 Tong Zi Po Road, Changsha 410013, Hunan Province
China
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0973-1482.194346

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 > Abstract 

Purpose: The balance between T helper (Th) cells Th1- and Th2-related cytokines plays a key role in the clinical process of acute coronary syndrome (ACS) and type 2 diabetes mellitus (T2DM) or impaired glucose tolerance (IGT). The objective of this study was to assess the status of Th1/Th2 cytokines in patients with ACS and T2D or IGT.
Methods: A total of 201 ACS patients were enrolled in the study. All ACS patients were divided into three groups: Group I-patients with normal glucose tolerance (NGT), Group II-patients with IGT and Group III-patients with T2D. We measured circulating Th1/Th2-type cytokines (interleukin [IL]-4, IL-13, interferon-gamma [IFN-γ], and tumor-necrosis factor-alpha [TNF-α]) using enzyme-linked immunosorbent assay and calculated the ratio of Th1/Th2.
Results: Significant elevations in serum levels of IL-4, IL-13, IFN-γ, and TNF-α were found in ACS-T2D and ACS-IGT groups compared to that in both ACS-NGT group and healthy individuals. Higher serum levels of IL-4, IL-13, and TNF-α were found in ACS-NGT group than that in the control group. Furthermore, IL-4 and IFN-γ concentrations were significantly higher in ACS-T2D patients than in ACS-IGT patients. IFN-γ/IL-4, IFN-γ/IL-13, and TNF-α/IL-4 ratios as markers of Th1/Th2 ratio were significantly higher for the ACS-T2D group and ACS-IGT group as compared to that in the ACS-NGT group and control group (P < 0.05).
Conclusion: Shifts in the balance of Th1/Th2 toward a predominance of Th1 may represent more severe inflammatory status in ACS patients with type T2D or IGT.

Keywords: Acute coronary syndrome, impaired glucose tolerance, T-helper 1/T-helper 2 profile, type 2 diabetes mellitus


How to cite this article:
Zhao SL, Mo ZH, He HH, Zhao LL, Xie YH. Imbalance of T-helper 1/T-helper 2 cytokines and impaired glucose tolerance among patient with acute coronary syndrome. J Can Res Ther 2018;14, Suppl S2:480-5

How to cite this URL:
Zhao SL, Mo ZH, He HH, Zhao LL, Xie YH. Imbalance of T-helper 1/T-helper 2 cytokines and impaired glucose tolerance among patient with acute coronary syndrome. J Can Res Ther [serial online] 2018 [cited 2019 Sep 17];14:480-5. Available from: http://www.cancerjournal.net/text.asp?2018/14/9/480/194346


 > Introduction Top


Acute coronary syndrome (ACS) is often caused by disruption of an atherosclerotic plaque, resulting in occlusion of the coronary artery [1] and the initial cellular and extracellular events that occur soon after ACS are characterized by a robust expression of a number of inflammatory cytokines.[2] Meanwhile, large evidence revealed that coronary plaque rupture can be triggered by various inflammatory cytokine response [3] and inflammatory cytokines might affect the stability of atherosclerotic plaque. In patients with ACS, type 2 diabetes mellitus (T2DM) or impaired glucose tolerance (IGT) continues to be a major cause of morbidity and mortality.[4] It has been recognized that diabetes is a main risk factor for atherosclerosis process which lead to ACS.[5] Besides, people with IGT have long been considered to be at high risk for both T2D and cardiovascular diseases. Studies have revealed that chronic vascular complications in T2D or IGT are the deteriorating conditions underlined by inflammation [6] and the hyperglycemia associated with T2D or IGT can lead to inflammation.[7] These prior studies suggested that there might be more severe inflammatory status in patients with ACS and T2D or IGT.

T-helper (Th) cells are key regulators of inflammatory response as they secrete a wide array of cytokines.[8] Interleukin-4 (IL-4) and IL-13, which are mainly secreted by Th2 lymphocytes, have been proved to be associated with inflammation reduction and improvement of symptoms in ACS patients; meanwhile Th1 cytokines such as interferon-gamma (INF-γ) and tumor-necrosis factor-alpha (TNF-α) have been considered to increase inflammation, therefore leading to disease progression and worsening of symptoms.[9] Th2 and Th1 cytokines may have mutual effects with each other and together have great influence on the progression of many diseases including ACS.

There is a need to identify the status of Th1/Th2 cytokines in patients with ACS and IGT or T2DM to facilitate screening and the development of novel strategies to prevent disease progression and related complications. In this study, we aimed to investigate the imbalance of Th1/Th2 cytokines in such patients to figure out more evidence about this potential therapeutic and prognostic target.


 > Methods Top


Ethics statement

The study was approved by the authors' hospital, and the study protocol complied with the guidelines set out in the Declaration of Helsinki. All subjects gave written informed consent before participation.

Study population

A total of 201 consecutive patients, admitted with ACS myocardiac infarction with ST segment elevation;[10] myocardiac infarction without ST segment elevation;[11] unstable angina pectoris [11] to the authors' hospital were enrolled in this study. Seventy age- and sex-matched healthy subjects were enrolled as control group. T2D patients were defined as a history of DM, a fasting plasma glucose concentration ≥126 mg/dl, or the use of hypoglycemic medications.[12] IGT can be recognized by the results of an oral glucose tolerance test: 2-h postload plasma glucose ≥7.8 and <11.1 mmol/L (≥140 and <200 mg/dl)[13] and NGT is defined as blood glucose rises no higher than 140 mg/dl 2 h after the drink. Hypertension is defined as systolic blood pressure (SBP) >140 mmHg and diastolic blood pressure (DBP) >90 mmHg. Hyperlipidemia is defined as the abnormally elevated levels of any or all lipids and/or lipoproteins in the blood.

The exclusion criteria of this study included pregnancy, previous myocardial infarction, a history of heart failure, patients taking insulin, myocardiopathy or moderate/severe valvular heart disease, prior stroke, arterial or venous thromboembolic disease, peripheral artery disease, impaired renal function, liver dysfunction, active or recent infections (last month), a history of inflammatory or connective tissue disorders, chronic or occasional (last 3 weeks) anti-inflammatory or corticosteroid treatment, cancer, hematological disorders, previous major trauma, or surgery (within 3 months) and those with permanent pacemakers.

Clinical and laboratory assessment

Detailed baseline questionnaires were collected at study entry including age, sex, medical history, smoking history, and medication. Blood glucose levels were measured immediately before the procedure before any intravenous fluids were given to the patients. The levels of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, and glycated hemoglobin (HbA1C) were determined using standard laboratory methods. These assays were conducted in the main clinical laboratories of the authors' hospital. The samples for troponin I and creatine kinase myocardial band were collected before the procedure.

Peripheral blood (5–10 ml) was extracted from all the subjects in a fasting state in the following morning of the admission day. The time interval between symptom onset and blood sampling was no more than 24 h in all the included cases. Plasma was stored at −80°C for cytokine measurement. Serum levels of IL-4, IL-13, TNF-α, and IFN-γ were determined using commercially available enzyme-linked immunosorbent assay (ELISA) kits (eBioscience, Inc., San Diego, CA, USA) according to the manufacturers' protocol. Measurements were performed in duplicate, and the results were averaged. The sensitivities of IL-4 and IL-13 ELISA kits are 5 pg/ml and 4 pg/ml, and standard curve ranges are 15–375 pg/ml and 4–500 pg/ml. The sensitivities of IFN-γ and TNF-α ELISA kits are 15 pg/ml and 8 pg/ml, and standard curve ranges are 15–2000 pg/ml and 8–1000 pg/ml.

Coronary angiography and echocardiographic study

All patients had undergone recent coronary angiography before enrolment in the study. Coronary angiography was carried out by left-heart catheterization and arteriography using Judkins method [14] and a diameter stenosis of >70% stenosis on coronary angiography was considered hemodynamically significant.

The echocardiographic scans were analyzed by a reviewer who was blinded to the study design. The left ventricular end-systolic volume (LVESV) and the left ventricular end-diastolic volume (LVEDV) were measured using Simpson's method (Vivid-7; GE Medical System), and the left ventricular ejection fraction (LVEF, %) was calculated by (LVEDV − LVESV)/LVEDV ×100%.

Statistical analysis

All data analyses were performed in the computer package SPSS for Windows (version 17.0, Chicago, IL, USA). Data are presented as proportions, mean ± standard deviation (SD), geometric mean (SD range), or in the case of variables which did not conform to a normal or log-normal distribution, median (inter-quartile range). For independent samples, two-way comparisons for proportions were by Fisher's exact test, for normally distributed variables by Student's t-test, and for nonnormally distributed variables by Mann–Whitney U-test. P < 0.05 was considered statistically significant.


 > Results Top


Baseline patient characteristics

The baseline characteristics of the four groups are shown in [Table 1]. No significant difference of age, sex, SBP, DBP, heart rates, LVEDV, LVESV, and LVEF was observed among the four groups. The ACS-T2D group had more history of hyperlipidemia and hypertension than ACS-IGT group or ACS-NGT group; all three groups of ACS patients had more smoking history than control group. Moreover, patients in ACS-T2D and ACS-IGT groups had significantly higher body mass index (BMI) than patients in ACS-NGT group or control group.
Table 1: Comparison of baseline demographic and clinical characteristics of four groups

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Comparisons of serum levels of interleukin-4, interleukin-13, interferon-gamma, and tumor-necrosis factor-alpha among four groups

We found significant elevations in levels of IL-4, IL-13, IFN-γ, and TNF-α in ACS-T2D and ACS-IGT groups compared to that in both ACS-NGT group and healthy individuals. Higher serum levels of IL-4, IL-13, and TNF-α were found in ACS-NGT group than that in control group. In addition, IL-4 and IFN-γ concentrations were significantly higher in ACS-T2D patients than in ACS-IGT patients. Furthermore, higher serum levels of HbA1C, high-sensitivity C-reactive protein (hs-CRP), LDL-C, and N-terminal pro brain natriuretic peptide were found in an ACS-T2D group than that in the other three groups (P < 0.05). On the other hand, serum levels of HDL-C, TC, and TG did not differ significantly among the four groups (P > 0.05) [Table 2].
Table 2: Comparison of serum levels of interleukin-4, interleukin-13, interferon-γ, tumor-necrosis factor-α, and other clinical data of four groups

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Association between cytokine concentrations and clinical, metabolic, and inflammatory markers

By Spearman's analysis, we tested whether cytokine levels were correlated with age, key clinical and metabolic markers as well as with hs-CRP [Table 3]. The strongest correlations were observed in the analysis of IL-4 (SBP, r = 0.10; HbA1C, r = 0.16; HDL-C, r = −0.15; LDL-C, r = 0.25). Also notably, BMI (r = 0.25), LDL-C (r = 0.10) and TC (r = 0.33) were correlated with levels of IFN-γ significantly. Besides, correlations between hs-CRP and IL-13 (r = 0.13) as well as HbA1C and TNF-α (r = 0.42) were found significantly different.
Table 3: Correlation of cytokine levels with clinical, metabolic, and inflflammatory parameters

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Comparisons of T-helper 1/T-helper 2 ratios in four groups

Th1/Th2 ratio was defined based on the ratio of proinflammatory Th1-related cytokines INF-γ or TNF-α and anti-inflammatory Th2-related cytokines IL-4, or IL-13 and the median Th1/Th2 ratio was calculated for each group. IFN-γ/IL-4, IFN-γ/IL-13, and TNF-α/IL-4 ratios as markers of Th1/Th2 ratio were significantly higher for ACS-T2D group and ACS-IGT group as compared to the ACS-NGT group and control group (P < 0.05) [Table 4]. Moreover, TNF-α/IL-13 ratio was also higher in ACS-T2D group and ACS-IGT group comparing to the ACS-NGT group and control group, although the difference was not significant.
Table 4: Comparison of Th2/Th1 ratios in four groups

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 > Discussion Top


The results of this study revealed that ACS patients with T2D or IGT revealed higher levels of IL-4, IL-13, IFN-γ, and TNF-α compared with both ACS-NGT group and healthy individuals, and all three groups with ACS demonstrated higher cytokine levels than the control group. In addition, the findings suggested the potential association between clinical, metabolic, inflammatory markers, and cytokine concentrations. Blood pressure, BMI and concentrations of HbA1C, HDL-C, LDL-C, TC, and hs-CRP were shown to exhibit some effect on the release of Th1 and Th2 cytokines.

Th1 cells, which produce large quantities of IFN-γ and TNF-α, could activate macrophages and promote cell-mediated immunity. Th2 cells, which mainly produce IL-4, IL-5, IL-10, and IL-13, suppress Th1 cell activation and contribute to humoral immunity.[15] The observed significant increase in the level of Th1 and Th2 cytokines indicates enhancement of inflammatory state in ACS patients, supporting the argument that acute ischemia resulted from rupture of unstable atherosclerotic plaque could cause activation of the inflammatory process with subsequent increased synthesis of pro- and anti-inflammatory factors and cytokines secreted by activated leukocytes are critical determinants of tissue inflammation and atherosclerotic plaque stability.[16] Meanwhile, impaired glucose signaling in type 2 diabetes causes hyperglycemia, which stimulates insulin secretion. Sustained physiological hyperinsulinemia activates multiple genes involved in inflammation,[17] resulting in the increased release of inflammatory cytokines and their invasion to the tissues[7] causing functional disruption of the endothelium and accelerating plaque vulnerability in patients with ACS. Therefore, ACS patients with T2D showed higher levels of cytokines than those without T2D. Moreover, IGT is an intermediate condition in the transition between normality and diabetes. Subjects in this state have moderate insulin resistance and impaired insulin secretion,[18] and have a serious possibility of developing T2D. It is, therefore, necessary to take extra notice on this prediabetic states and factors that might influence disease development in ACS patients. Our results suggest that acute ischemia and hyperglycemia are risk factors for the elucidation of Th1/Th2 immune response in lymphocytes during ACS and diabetes.

Furthermore, the results of the study suggest a Th1/Th2 balance shift in favor of a Th1 cytokine profile which mainly includes pro-inflammatory cytokines in ACS patients with T2D or IGT versus ACS-NGT group and healthy individuals. In general, Th1 and Th2-mediated immunity are reciprocally regulated and maintain a balance in immune-mediated disease.[15] The balance of Th1/Th2 determines the outcome of a wide variety of immune responses involving infectious, allergic diseases, wound healing and diabetes [19] and Th1 and Th2 reactivities can be considered polarized forms of the immune response,[20] causing great effects on the outcome of vascular complications. In ACS patients with T2D or IGT, enhanced activation of proinflammatory factors augments the generation of reactive oxygen species, leading to increased oxidative stress and inflammation in vital tissues,[21],[22] and ultimately leads to impaired insulin endocytosis in endothelial cells, which in consequence, causing insulin resistance [23] which may influence independently the progression of coronary atherosclerotic plaques.[24] Szodoray et al. had reported that Th1 to Th2 ratio shifted towards a Th1 dominance in both ACS and stable coronary artery disease.[25] Recently, Jagannathan-Bogdan et al. demonstrated that T cells in T2DM patients were skewed toward a proinflammatory phenotype that requires monocytes for maintenance and promotes chronic inflammation through increased IFN-γ production.[26] In this study, the increased IFN-γ/IL-4, IFN-γ/IL-13, TNF-α/IL-4, and TNF-α/IL-13 ratio indicates prevailing activation of proinflammatory factors in ACS patients with T2D or IGT. Accordingly, the enhancement of circulating IFN-γ and TNF-α and the subsequent effect on IL-4 and IL-13 seen in these patients may play an important role in related inflammatory response that might relate to the pathogenesis of this disorder and affect the clinical development of disease in such patients.


 > Conclusion Top


The data from this study demonstrate, for the first time, that imbalance of Th1/Th2 ratio in the systemic circulation of ACS patients with T2D or IGT shifted toward the pro-inflammatory Th1 profile response. The results may serve as a promising diagnostic parameter on disease activity, progression as well as a potential marker of response to therapy in these patients.

Limitations

This study had some limitations. First, the number of patients was relatively small, and we only conducted a one-point measurement of cytokine patterns. Second, we did not evaluate the long-term outcome of the patients. In the future, we are going to involve larger cohorts of patients and conduct longer follow-up observations to evaluate the prognostic value of Th1/Th2 ratio in these patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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  [Table 1], [Table 2], [Table 3], [Table 4]



 

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