Osteopontin Expression in Cardiomyocytes Is Increased in Pediatric Patients With Sepsis or Pneumonia

Involvement of Mitophagy in Aluminum Oxide Nanoparticle-Induced Impairment of Learning and Memory in Mice

Aluminum oxide nanoparticles (nano-aluminum) have been known to be widespread in the environment for decades. Exposure to nano-aluminum may impair learning and memory, but the potential mechanism has not yet been elucidated. In neurons, efficient clearance of damaged mitochondria through mitophagy plays an important role in mitochondrial energy supply, neuronal survival, and health. However, abnormal mitophagy induces accumulation of damaged mitochondria, which induces cellular dysfunction, contributing to the impairment of learning and memory. It is currently unclear whether nano-aluminum interferes with the function of nerve cells through mitophagy, leading to learning and memory disorders. Institute of Cancer Research (ICR) female mice were randomly divided into four groups, and treated with normal saline (control) and 50 nm nano-aluminum at concentrations of 25, 50, and 75 mg/kg for 30 days. Our results showed that exposure to nano-aluminum impaired the spatial learning and memory of mice. Superoxide dismutase levels decreased, whereas the levels of malondialdehyde increased. Moreover, there were significant pathological changes in the ultra-structure and function of mitochondria. Finally, expression of autophagy-related proteins LC3-II and Beclin-1 was upregulated and p62 expression decreased, but the expression of apoptotic and necrosis-related proteins had no significant difference among groups. Our results suggest that learning and memory impairment induced by nano-aluminum could be related to mitophagy.

Nuclear Osteopontin Is a Marker of Advanced Heart Failure and Cardiac Allograft Vasculopathy: Evidence From Transplant and Retransplant Hearts

Background

Heart transplant is the gold standard therapy for patients with advanced heart failure. Over 5,500 heart transplants are performed every year worldwide. Cardiac allograft vasculopathy (CAV) is a common complication post-heart transplant which reduces survival and often necessitates heart retransplantation. Post-transplant follow-up requires serial coronary angiography and endomyocardial biopsy (EMB) for CAV and allograft rejection screening, respectively; both of which are invasive procedures. This study aims to determine whether osteopontin (OPN) protein, a fibrosis marker often present in chronic heart disease, represents a novel biomarker for CAV.

Methods

Expression of OPN was analyzed in cardiac tissue obtained from patients undergoing heart retransplantation using immunofluorescence imaging (n = 20). Tissues from native explanted hearts and three serial follow-up EMB samples of transplanted hearts were also analyzed in five of these patients.

Results

Fifteen out of 20 patients undergoing retransplantation had CAV. 13/15 patients with CAV expressed nuclear OPN. 5/5 patients with multiple tissue samples expressed nuclear OPN in both 1^st and 2^nd explanted hearts, while 0/5 expressed nuclear OPN in any of the follow-up EMBs. 4/5 of these patients had an initial diagnosis of dilated cardiomyopathy (DCM).

Conclusion

Nuclear localization of OPN in cardiomyocytes of patients with CAV was evident at the time of cardiac retransplant as well as in patients with DCM at the time of the 1^st transplant. The results implicate nuclear OPN as a novel biomarker for severe CAV and DCM.