Purpose of review: Oxalate is a metabolic end-product promoting the formation of calcium oxalate crystals in urine. Massive urine oxalate excretion occurs in genetic diseases, mainly primary hyperoxaluria type I and II, threatening renal function. Ethylene glycol poisoning may induce the precipitation of calcium oxalate crystals in renal tubules, leading to acute renal failure. In both cases, oxalate results from glyoxylate transformation to oxalate in the liver, by lactate dehydrogenase (LDH) enzymes, especially the LDH-5 isoenzyme. The purpose of the review is to highlight LDH as a potential therapeutic target according to recent publications.
Recent findings: Genetic therapy targeting LDH metabolism decreases urine oxalate excretion in rodents. Stiripentol is an antiepileptic drug that has been shown recently to inhibit neuronal LDH-5 isoenzyme. Stiripentol was hypothesized to reduce hepatic oxalate production and urine oxalate excretion. In vitro, stiripentol decreases oxalate synthesis by hepatocytes. In vivo, stiripentol oral administration decreases urine oxalate excretion in rats and protects renal function and renal tissue against ethylene glycol intoxication and chronic calcium oxalate crystalline nephropathy.
Summary: The use of stiripentol in-vitro and in-vivo highlights that targeting hepatic LDH by pharmacological or genetic tools may decrease oxalate synthesis, deserving clinical studies.