Physiological clearance of amyloid-beta by the kidney and its therapeutic potential for Alzheimer's disease.

Amyloid-ß (Aß) accumulation in the brain is a pivotal event in the pathogenesis of Alzheimer's disease (AD), and its clearance from the brain is impaired in sporadic AD. Previous studies suggest that approximately half of the Aß produced in the brain is cleared by transport into the periphery. However, the mechanism and pathophysiological significance of peripheral Aß clearance remain largely unknown. The kidney is thought to be responsible for Aß clearance, but direct evidence is lacking. In this study, we investigated the impact of unilateral nephrectomy on the dynamic changes in Aß in the blood and brain in both humans and animals and on behavioural deficits and AD pathologies in animals. Furthermore, the therapeutic effects of the diuretic furosemide on Aß clearance via the kidney were assessed. We detected Aß in the kidneys and urine of both humans and animals and found that the Aß level in the blood of the renal artery was higher than that in the blood of the renal vein. Unilateral nephrectomy increased brain Aß deposition; aggravated AD pathologies, including Tau hyperphosphorylation, glial activation, neuroinflammation, and neuronal loss; and aggravated cognitive deficits in APP/PS1 mice. In addition, chronic furosemide treatment reduced blood and brain Aß levels and attenuated AD pathologies and cognitive deficits in APP/PS1 mice. Our findings demonstrate that the kidney physiologically clears Aß from the blood, suggesting that facilitation of Aß clearance via the kidney represents a novel potential therapeutic approach for AD.

Mitochondrial pyruvate carrier 1 functions as a tumor suppressor and predicts the prognosis of human renal cell carcinoma.

Invasion and subsequent metastasis are major characteristics of malignant human renal cell carcinoma (RCC), though the mechanisms remain elusive. Mitochondrial pyruvate carrier (MPC), a key factor that controls pyruvate transportation in mitochondria, is frequently dysregulated in tumor cells and loss of MPC predicts poor prognosis in various types of cancer. However, the clinical relevance and functional significance of MPC in RCC remain to be elucidated. In this study, we investigated the expression of MPC1 and MPC2 in specimens from RCC patients and observed downregulation of MPC1, but not MPC2, in RCC tissues compared with adjacent non-cancerous tissue. Moreover, RCC patients with higher MPC1 expression exhibited longer overall survival rate than those with lower MPC1. Functionally, MPC1 suppressed the invasion of RCC cells in vitro and reduced the growth of RCC cells in vivo, possibly through inhibition of MMP7 and MMP9. Further studies revealed that loss of MPC1 was induced by hypoxia in RCC cells, and notably, MPC1 expression, was negatively correlated with HIF1α expression in RCC cells and patient samples. Taken together, our results identify anti-tumor function of MPC1 in RCC and revealed MPC1 as a novel prognostic biomarker to predict better patient survival.

Efficacy of N-Acetylcysteine in Preventing Acute Kidney Injury After Cardiac Surgery: A Meta-Analysis Study.

PURPOSE: To evaluate whether perioperative N-acetylcysteine (NAC) administration reduces the risk of cardiac surgery associated acute kidney injury (CSA-AKI). MATERIALS AND METHODS: A systematic literature review (Medline, PubMed, Cochrane, Biomedical central, Google Scholar) identified 10 studies (1391 patients; 695 NAC and 696 placebo) that compared the efficacy and adverse effects of perioperative NAC administration for CSA-AKI prevention in adults undergoing elective cardiac surgery. Meta-analysis was performed using Comprehensive Meta-Analysis statistical software. RESULTS: Patients in the NAC-treated and placebo groups had similar rate of CSA-AKI occurrence, change in creatinine levels, as well as the in-hospital mortality rate (RR = 0.841, 95% CI = 0.691 to 1.023, p = 0.083; pooled difference in means = -0.328, 95% CI = -0.712 to 0.056, p = 0.094; RR = 0.741, 95% CI = 0.388 to 1.418, p = 0.366, respectively). CONCLUSIONS: Our study does not support perioperative NAC administration as a mean to reduce the risk of CSA-AKI.