Microbiota manipulation to prevent oxalate kidney stone formation

Oral supplementation with probiotics, potassium citrate, and magnesium in reducing crystalluria in stone formers: A phase II study

INTRODUCTION

Crystalluria is an important indicator of renal stone recurrence. Mechanisms underlying urinary stone formation are still not fully understood and raising interests has been giving to intestinal commensal bacteria for their contribute in maintaining urinary solutes equilibrium. The aim of our phase II study was to examine the administration of potassium citrate, magnesium and probiotics in order to reduce crystalluria.

MATERIALS AND METHODS

Since May 2021, we enrolled 23 patients candidates for ureterorenolithotripsy for calcium oxalate kidney stones with crystalluria and a normal metabolic profile. The analysis was validated by the Institution's Ethical Committee (no. approval STS CE Lazio 1/N-823). At discharge, patients were provided with daily food supplementation for 20 days of 1 billion Lactobacillus paracasei LPC09, 1 billion Lactobacillus plantarum LP01, 1 billion Bifidobacterium breve BR03, potassium (520 mg), citrate (1400 mg), and magnesium (80 mg). Crystalluria was re-assessed at 1, 3, 6, and 12-months follow-up by polarized light microscopy.

RESULTS

After one month from the oral supplementation, no patient reported crystalluria; at 3 months, among the 20 participants available for re-evaluation, still no patient reported crystalluria. Instead, crystalluria was reported in three patients (15%) at 6 months, and in five patients (25%) at 12 months follow-up.

CONCLUSIONS

The oral supplementation with Lactobacillus spp. and Bifidobacterium spp. was found able to reduce the prevalence of crystalluria in a cohort of patients with diagnosis of calcium oxalate kidney stones with crystalluria candidate to ureterorenolithotripsy.

Association between daily sitting time and kidney stones based on the National Health and Nutrition Examination Survey (NHANES) 2007-2016: a cross-sectional study

BACKGROUND

Kidney stones are among the most common urological conditions affecting ~9% of the world population. Although some unhealthy diets and unhealthy lifestyles are reportedly risk factors for kidney stone, the association between daily sitting time and kidney stone has not been explored.

MATERIALS AND METHODS

This large-scale, cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) database 2007-2016. Kidney stone history and daily sitting time were retrieved from the questionnaire and 24 hour (h) recall interviews. Logistic regression and subgroup analysis were conducted to investigate the association. The analysis was further stratified by vigorous recreational activity.

RESULTS

A total of 19 188 participants aged ≥20 years with complete information were included in this study. The overall prevalence of kidney stone was 9.6%. Among participants without vigorous recreational activity, a trend towards an increasing prevalence of kidney stone was observed with increased daily sitting time. However, the trend was not observed in individuals who participated in vigorous recreational activity, as they experienced a decreased risk of kidney stone despite having a daily sitting time of 6-8 h (crude model OR=0.659, 95% CI: 0.457-0.950, P =0.028), indicating that vigorous recreational activity may partially attenuate the detrimental effect of prolonged sitting time.

CONCLUSION

Our study revealed an increasing trend of prevalence of kidney stone with increased daily sitting time among the population not performing vigorous recreational activity despite the difference was nonsignificant. Vigorous recreational activity may modify the association between daily sitting time and kidney stone. More prospective cohort studies are warranted to further examine this association.

Update on the Effect of the Urinary Microbiome on Urolithiasis

Microbiota are ecological communities of commensal, symbiotic, and pathogenic microorganisms. The microbiome could be involved in kidney stone formation through hyperoxaluria and calcium oxalate supersaturation, biofilm formation and aggregation, and urothelial injury. Bacteria bind to calcium oxalate crystals, which causes pyelonephritis and leads to changes in nephrons to form Randall's plaque. The urinary tract microbiome, but not the gut microbiome, can be distinguished between cohorts with urinary stone disease (USD) and those without a history of the disease. In the urine microbiome, the role is known of urease-producing bacteria (Proteus mirabilis, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Providencia stuartii, Serratia marcescens, and Morganella morganii) in stone formation. Calcium oxalate crystals were generated in the presence of two uropathogenic bacteria (Escherichia coli and K. pneumoniae). Non-uropathogenic bacteria (S. aureus and Streptococcus pneumoniae) exhibit calcium oxalate lithogenic effects. The taxa Lactobacilli and Enterobacteriaceae best distinguished the healthy cohort from the USD cohort, respectively. Standardization is needed in urine microbiome research for urolithiasis. Inadequate standardization and design of urinary microbiome research on urolithiasis have hampered the generalizability of results and diminished their impact on clinical practice.