Dietary hyperoxaluria is not reduced by treatment with lactic acid bacteria

Abstract

BackgroundSecondary hyperoxaluria either based on increased intestinal absorption of oxalate (enteric), or high oxalate intake (dietary), is a major risk factor of calcium oxalate urolithiasis. Oxalate-degrading bacteria might have beneficial effects on urinary oxalate excretion resulting from decreased intestinal oxalate concentration and absorption.MethodsTwenty healthy subjects were studied initially while consuming a diet normal in oxalate. Study participants were then placed on a controlled oxalate-rich diet for a period of 6 weeks. Starting with week 2 of the oxalate-rich diet, participants received 2.6 g/day of a lactic acid bacteria preparation for 5 weeks. Finally, subjects were examined 4 weeks after treatment while consuming again a normal-oxalate diet. Participants provided weekly 24-hour urine specimens. Analyses of blood samples were performed before and at the end of treatment.ResultsUrinary oxalate excretion increased significantly from 0.354 ± 0.097 at baseline to 0.542 ± 0.163 mmol/24 h under the oxalate-rich diet and remained elevated until the end of treatment, as did relative supersaturation of calcium oxalate. Plasma oxalate concentration was significantly higher after 5 weeks of treatment compared to baseline. Four weeks after treatment, urinary oxalate excretion and relative supersaturation of calcium oxalate fell to reach initial values.ConclusionsPersistent dietary hyperoxaluria and increased plasma oxalate concentration can already be induced in healthy subjects without disorders of oxalate metabolism. The study preparation neither reduced urinary oxalate excretion nor plasma oxalate concentration. The preparation may be altered to select for lactic acid bacteria strains with the highest oxalate-degrading activity.

Calcium Oxalate Nephrolithiasis and Gut Microbiota: Not just a Gut-Kidney Axis. A Nutritional Perspective

“…Since the late 1990s, several intervention studies have investigated whether the administration of Oxalobacter or other probiotic blends engineered with oxalate-degrading functionalities could result in the reduction of lithogenic risk (Table 2) [36][37][38][39][40][41][42][43]. All these studies were conducted on small samples (the largest one having enrolled only 42 participants) and were highly heterogeneous for the type and duration of the intervention and for the clinical characteristics of participants, ranging from healthy volunteers to children with severe forms of primary hyperoxaluria ( Table 2).…”

“…All these studies were conducted on small samples (the largest one having enrolled only 42 participants) and were highly heterogeneous for the type and duration of the intervention and for the clinical characteristics of participants, ranging from healthy volunteers to children with severe forms of primary hyperoxaluria ( Table 2). The results were conflicting overall, with some studies reporting significant reductions in urinary oxalate excretion after probiotic treatment [36][37][38][40][41][42], and others showing no changes from baseline [39,43] (Table 2). The clinical significance of detected reductions in urinary oxalate excretion was also uncertain, since oxalate excretion is a surrogate outcome of stone recurrence, and only one of many elements concurring to the definition of lithogenic risk.…”

The Handling of Oxalate in the Body and the Origin of Oxalate in Calcium Oxalate Stones

“…Secondary hyperoxaluria is the chief risk factor for urolithiasis which can be caused by either an increase in absorption of oxalate in the intestine or intake of a highoxalate diet [45]. For many years it was thought that the dietary source of oxalate contributed only 10-15% of the daily oxalate excretion.…”

The role of intestinal oxalate transport in hyperoxaluria and the formation of kidney stones in animals and man

“…Human studies [165–168] and earlier work [21, 163] have focused primarily on Oxalobacter , in addition to some commercial probiotic preparations of various formulations of Lactobacillus and Bifidobacterium strains (Oxadrop, VSL#3, and including a symbiotic preparation Agri-King Synbiotic [167]). However, these studies have shown inconsistent results.…”