Myocardial ischemia triggers neurohumoral activation of the cardiosplenic axis. In rodents, adverse outcomes occur upon prolonged entrance of mononuclear cells from the spleen into myocardial tissue. The purpose of this study is to assess the features of spleen structure in patients with fatal myocardial infarction (MI), the dynamics of macrophage infiltration of the spleen and its relationship with cardiac macrophage infiltration and unfavorable outcomes. Using immunohistochemistry techniques, we analyzed the macrophage infiltration of the spleen and myocardium sections collected from patients (n = 30) with fatal MI. The spleen of the patients was decreased and showed a predominance of red pulp with a high concentration of CD68+ and stabilin-1+ cells. The white pulp contained many medium and small follicles and a lower concentration of CD68+ and stabilin-1+ cells, which was comparable to that in the infarct area of the myocardium. The concentration of CD68+ and stabilin-1+ cells increased in the myocardium in the late period of MI, but did not show any dynamics in the spleen. A high number of CD68+ cells in the red pulp and reduced concentration of stabilin-1+ cells in the white pulp were associated with unfavorable post-infarction outcomes. These fundamental findings could be a basis for the development of new personalized therapeutic and diagnostic approaches for the treatment of MI and its complications.

No abstract

Background. It has been shown that prognosis following acute myocardial infarction (MI) strongly correlates with intensity of inflammatory reactions in response to myocardial injury. Thereby diagnostic methods for myocardial post-infarction inflammation (PII) monitoring are needed. Scintigraphy with somatostatin receptor targeted radiotracers has prospects for PII imaging, but its clinical value is poorly studied.Methods. Six patients with ST-segment elevation anterior myocardial infarction (STEMI) were examined by chest SPECT/СT with 99mTc-Tektrotyd and rest myocardial perfusion scintigraphy (MPS) at subacute and remote (8 th month) period of the disease. Parameters of both scintigraphic methods were estimated.Results. In subacute stage of MI myocardial perfusion defects were revealed in all 6 patients (mean SRS 11.83 ± 8.89), 99mTc-Tektrotyd uptake in myocardium was revealed in 3 of 6 patients. At remote period intense uptake of 99mTc-Tektrotyd was found only in 1 patient. This uptake was more spread and clears, comparing with accumulation in subacute stage of AMI.Conclusion. Myocardium scintigraphy with 99mTc-Tektrotyd allows identifying overexpression of somatostatin receptors in areas of recent and old myocardium infarction. In some patients the radiopharmaceutical uptake may expands to a remote period of the disease. Further larger studies and histological validation of scintigraphic results are needed.