Non-invasive Assessment of Inflammatory Markers MIP-1 Alpha and IL-6 in Saliva of Post Myocardial Infarction and Stage 4 Periodontitis Patients

Periodontitis is an immunoinflammatory disease caused by microorganisms leading to sequential loss of the supporting structures of periodontium, resulting in periodontal pocket formation, gingival recession eventually leading to tooth loss.\[1\] A bacterial plaque is formed during the destructive changes of the periodontium which initiates a host of inflammatory and immune responses.\[2\] These inflammatory responses may also cause an increase in inflammatory activities in atherosclerotic lesions in the coronary arteries resulting in the increased risk of cardiovascular events like myocardial infarction.\[3\] Myocardial infarction (MI) is a cardiovascular condition that occurs when there is deprivation of oxygen in the heart muscle is due to the sudden interruption of the blood supply resulting from the coronary artery blockage by a plaque causing myocardial ischemia and cell death. Inflammation is pivotal in the initiation and progression of atherosclerosis. Various cytokines and chemokines are released during inflammation.\[4\] These inflammatory markers may have diagnostic potential for the detection of various inflammatory diseases.\[5\] Macrophages secrete macrophage inflammatory protein-1 alpha (MIP-1 alpha) which recruits inflammatory cells, inhibits stem cells, and activates bone resorption cells.\[6\] Interleukin-6 (IL-6) is produced in response to tissue injury and infection and contributes to the differentiation of B cells, the proliferation of T cells, and bone resorption.\[7\] The levels of these inflammatory markers are seen to be increased in inflammatory conditions, which include myocardial infarction and stage 4 periodontitis. Therefore, this study aims to assess the levels of these inflammatory markers in patients with myocardial infarction and periodontitis.

This was a cross-sectional study involving the patients of the department of periodontics and department of cardiology.

Patients included in the study were categorized into four groups: (1) group 1-healthy subjects, (2) group 2-stage 4 periodontitis patients, (3) group 3- post-MI patients with stage 4 periodontitis, (4) group 4- post-MI patients without periodontitis.

The severity of the periodontitis was assessed by a periodontist. The diagnosis of acute MI was made by the cardiologists. Oral health assessment in acute MI patients was done at the subjects' bedside after stabilization of the patient, so as not to interfere with the ongoing medical treatment. Subjects' identification was kept confidential.

All samples were collected from patients admitted within 48 hours of their cardiac event. Patients were diagnosed as acute ST-elevation myocardial infarction (STEMI) based on the elevation of ST segments on the electrocardiogram(ECG) by 0.1mV in contiguous leads in patients with signs and symptoms of myocardial ischemia and/ or development of new left bundle branch block, along with increased cardiac biomarkers. Non-ST-elevation myocardial infarction (NSTEMI) was diagnosed in patients with signs and symptoms of myocardial ischemia and depression in ST-segment on the ECG or new Q wave pathology along with elevation of cardiac biomarkers.\[8\] Stage four periodontitis was diagnosed using the World Workshop 2017 classification.\[9\] Subjects who had undergone oral prophylaxis or periodontal surgery in the past 6 months were not included in the study. Smokers, pregnant women, lactating mothers, and those on medication (anti-microbial, non-steroidal anti-inflammatory drugs) in the past 3 months as well as those with other chronic systemic diseases were excluded from the study. These were all excluded as each would affect the levels of biomarkers.

Eligibility Criteria:
Inclusion Criteria:

* subjects who had MI
* who had stage 4 periodontal disease

Exclusion Criteria:

* subjects who did not have MI
* subjects who had systemic disease other than MI
* subjects who had medication in the past 3 months
* smokers
* pregnant and lactating women