Serum Mitochondrial Quality Control Related Biomarker Levels are Associated with Organ Dysfunction in Septic Patients

Restoring the infected powerhouse: Mitochondrial quality control in sepsis

Sepsis is a dysregulated host response to an infection, characterized by organ failure. The pathophysiology is complex and incompletely understood, but mitochondria appear to play a key role in the cascade of events that culminate in multiple organ failure and potentially death. In shaping immune responses, mitochondria fulfil dual roles: they not only supply energy and metabolic intermediates crucial for immune cell activation and function but also influence inflammatory and cell death pathways. Importantly, mitochondrial dysfunction has a dual impact, compromising both immune system efficiency and the metabolic stability of end organs. Dysfunctional mitochondria contribute to the development of a hyperinflammatory state and loss of cellular homeostasis, resulting in poor clinical outcomes. Already in early sepsis, signs of mitochondrial dysfunction are apparent and consequently, strategies to optimize mitochondrial function in sepsis should not only prevent the occurrence of mitochondrial dysfunction, but also cover the repair of the sustained mitochondrial damage. Here, we discuss mitochondrial quality control (mtQC) in the pathogenesis of sepsis and exemplify how mtQC could serve as therapeutic target to overcome mitochondrial dysfunction. Hence, replacing or repairing dysfunctional mitochondria may contribute to the recovery of organ function in sepsis. Mitochondrial biogenesis is a process that results in the formation of new mitochondria and is critical for maintaining a pool of healthy mitochondria. However, exacerbated biogenesis during early sepsis can result in accumulation of structurally aberrant mitochondria that fail to restore bioenergetics, produce excess reactive oxygen species (ROS) and exacerbate the disease course. Conversely, enhancing mitophagy can protect against organ damage by limiting the release of mitochondrial-derived damage-associated molecules (DAMPs). Furthermore, promoting mitophagy may facilitate the growth of healthy mitochondria by blocking the replication of damaged mitochondria and allow for post sepsis organ recovery through enabling mitophagy-coupled biogenesis. The remaining healthy mitochondria may provide an undamaged scaffold to reproduce functional mitochondria. However, the kinetics of mtQC in sepsis, specifically mitophagy, and the optimal timing for intervention remain poorly understood. This review emphasizes the importance of integrating mitophagy induction with mtQC mechanisms to prevent undesired effects associated with solely the induction of mitochondrial biogenesis.

Prognostic value of dynamic cardiac biomarkers in patients with acquired refractory thrombocytopenic purpura: A retrospective study in Chinese population

Introduction

Thrombotic thrombocytopenic purpura (TTP) is becoming a curable disease with the introduction of therapeutic plasma exchange (TPE). However, cardiovascular complications remain essential causes of mortality in patients with refractory TTP, while the association of cardiac biomarkers with the prognosis of TTP warrants further investigation.

Methods

Patients admitted to the First Affiliated Hospital of Soochow University for refractory TTP from 2013 through 2020 were included in this retrospective study. Clinical characteristics were collected from electronic health records. Biomarker levels on admission and post TPE were recorded. Logistic regression was adopted to identify risk factors for mortality.

Results

A total of 78 patients with refractory TTP were included in this study. Twenty‐one patients died during hospitalization, with a mortality rate of 26.9%. High‐sensitivity cardiac troponin T (hs‐cTnT), N‐terminal probrain natriuretic peptide (NT‐proBNP), and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ratios (AAR) were increased in deceased patients compared with the survival group. Multivariate analysis showed that AAR after TPE was associated with overall mortality (OR: 4.45, 95% CI 1.09–18.19). The areas under the receiver operator characteristic curve (AUC) of AAR, hs‐cTnT, and NT‐proBNP for the association with mortality were 0.814, 0.840, and 0.829, respectively.

Conclusion

Higher post‐TPE cardiac biomarker levels are associated with increased in‐hospital mortality in patients with refractory TTP.