QPRT and acute kidney injury: Further investigation showed that HDD could upregulate nicotinamide adenine dinucleotide (NAD+) biosynthesis-related enzymes quinolinate phosphoribosyltransferase, nicotinamide mononucleotide adenylyltransferase 1, and nicotinamide phosphoribosyltransferase to replenish NAD+ content in the kidney of AKI mice.