struvite and Hyperoxaluria

Microorganisms are one of the important factors for urinary calculi formation. While urease-positive bacteria and nanobacteria contribute to stone formation, Oxalobacter formigenes rods play a protective role against the development of urolithiasis. Proteus mirabilis alkaline environment of the urinary tract and cause crystallization mainly of struvite (magnesium ammonium phosphate). However, nanobacteria, due to the possibility of apatite deposition on the surface of their cells, have long been considered as an etiological factor of urinary calculi consisting of calcium phosphates. O. formigenes is an anaerobe using oxalate as the main source of carbon and energy and occurs as natural gastrointestinal microflora of humans and animals. These bacteria control the amount of oxalate excretion degrading oxalates and regulating their transport by intestinal epithelium. Lower colonization of the human colon by O. formigenes can cause increased oxalate excretion and lead to the development of oxalate urolithiasis. Due to the positive influence of O. formigenes, there is ongoing research into the use of this microorganism as a probiotic in the prophylaxis or treatment of hyperoxaluria, both secondary and primary. The results of these studies are very promising, but they still require continuation. Future studies focus on the exact characteristics of O. formigenes including their metabolism and the development of methods for applying as a therapeutic agent the bacteria or their enzymes degrading the oxalate.

Topics: Animals; Calcium Oxalate; Crystallization; Humans; Hyperoxaluria; Intestinal Mucosa; Magnesium Compounds; Nephrolithiasis; Oxalates; Oxalobacter formigenes; Phosphates; Probiotics; Proteus mirabilis; Struvite; Urease

Topics: Calcium; Citric Acid; Colic; Glycoproteins; Humans; Hyperoxaluria; Kidney Calculi; Magnesium Compounds; Phosphates; Recurrence; Risk Factors; Struvite; Uric Acid

The cause of urinary stone disease can now be detected in approximately 80% of patients. Effective treatment can substantially reduce the recurrence of urinary calculi. Proper therapy depends on a thorough understanding of the physiology of calcium, oxalate, uric acid, cystine, and struvite formation and the medication developed for prevention. This article reviews the physiologic basis of urinary stone management in a straightforward, understandable fashion.

Topics: Acetazolamide; Calcium; Carbonic Anhydrase Inhibitors; Citrates; Cystinuria; Humans; Hyperoxaluria; Magnesium Compounds; Phosphates; Struvite; Urease; Uric Acid; Urinary Calculi

Fifty-four patients with infected renal lithiasis underwent complete metabolic evaluation searching for underlying factors contributing to stone formation including urine analysis and culture. Metabolic abnormalities were significantly more present in patients with mixed infected stones (struvite+/-apatite and calcium oxalate) than in patients with pure infected stones (struvite+/-carbonate apatite): hypercalciuria in 40%, hyperoxaluria in 34% and hyperuricosuria in 28% (p < 0.05). Urinary excretion of citrate was low in both groups without statistically significant difference (238+/-117 mg/24 h vs 214+/-104 mg/24/h, t = 0.72, p = 0.5). The few metabolic abnormalities present in patients with pure infected stones should suggest that urinary tract infection could change the urine chemistry in a lithogenic direction and be only cause of stone formation.

Topics: Adolescent; Adult; Aged; Apatites; Calcium Oxalate; Citric Acid; Female; Follow-Up Studies; Humans; Hypercalciuria; Hyperoxaluria; Kidney Calculi; Male; Middle Aged; Nephrolithiasis; Struvite; Uric Acid; Young Adult