Discussion
Organ failure, or multiple organ failure, is an important reason for the death of elderly people, mostly those over 70 years old. Organ failure includes chronic diseases of important body organs such as trachea, heart, kidney, and brain17. Complications include shortness of breath, rapid drop in blood pressure, hypoxia of lips and nails, unresponsiveness of the optic nerve, hazy consciousness, hypoxia of blood, shock, coma, etc18,19. sST2 protein belongs to the interleukin 1 receptor family and can be produced by cardiomyocytes and cardiac fibroblasts when they are subjected to mechanical tension4. sST2 antagonizes the activation of IL-33 pathway and promotes the occurrence of cardiomyocyte hypertrophy and myocardial fibrosis20, and is increasingly regarded as a new marker for the diagnosis of heart failure. With the deepening of research, published data have shown that sST2 was involved in airway inflammation21, pulmonary hypertension22, schizophrenia23 and other diseases. As a plasticity population, CD4+T cells play an important role in the process of tissue damage and repair. For example, in the inflammatory environment, CD4+T cells differentiate into Th17 and then participate in myocardial inflammatory injury24, kidney25 and liver fibrosis26, etc. Therefore, the origin of sST2 and whether it is involved in the regulation of CD4+T cells differentiation and thus in OF are the focus of research.
The present results demonstrate that the expression of the inflammatory mediator IL-1, IL-6 and TNF-α were increased in peripheral blood serum of OF patients caused by inflammatory injury and the serum sST2 levels were also significantly up-regulated compare with NC. It suggests that sST2 can be used as a screening index for OF. At the same time, we also found that the number of CD4+T cells in peripheral blood decreased in patients with increased sST2. Additionally, some data show that IL-33/ST2 axis could regulate the proliferation of regulatory T cells (Treg)27, whether it suggests that sST2 may regulate CD4+T cells function and participate in OF remains to be confirmed.
In conclusion, the regulation of sST2 on OF is partly dependent on CD4+T cells, and sST2 is an important screening indicator for the diagnosis of organ failure.