Changes in NAD and Lipid Metabolism Drive Acidosis-Induced Acute Kidney Injury.
J Am Soc Nephrol
; 32(2): 342-356, 2021 02.
Article
em En
| MEDLINE
| ID: mdl-33478973
ABSTRACT
BACKGROUND:
The kidney plays an important role in maintaining normal blood pH. Metabolic acidosis (MA) upregulates the pathway that mitochondria in the proximal tubule (PT) use to produce ammonia and bicarbonate from glutamine, and is associated with AKI. However, the extent to which MA causes AKI, and thus whether treating MA would be beneficial, is unclear.METHODS:
Gavage with ammonium chloride induced acute MA. Multiphoton imaging of mitochondria (NADH/membrane potential) and transport function (dextran/albumin uptake), oxygen consumption rate (OCR) measurements in isolated tubules, histologic analysis, and electron microscopy in fixed tissue, and urinary biomarkers (KIM-1/clara cell 16) assessed tubular cell structure and function in mouse kidney cortex.RESULTS:
MA induces an acute change in NAD redox state (toward oxidation) in PT mitochondria, without changing the mitochondrial energization state. This change is associated with a switch toward complex I activity and decreased maximal OCR, and a major alteration in normal lipid metabolism, resulting in marked lipid accumulation in PTs and the formation of large multilamellar bodies. These changes, in turn, lead to acute tubular damage and a severe defect in solute uptake. Increasing blood pH with intravenous bicarbonate substantially improves tubular function, whereas preinjection with the NAD precursor nicotinamide (NAM) is highly protective.CONCLUSIONS:
MA induces AKI via changes in PT NAD and lipid metabolism, which can be reversed or prevented by treatment strategies that are viable in humans. These findings might also help to explain why MA accelerates decline in function in CKD.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Acidose
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Metabolismo dos Lipídeos
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Injúria Renal Aguda
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Túbulos Renais
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NAD
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article