struvite and Nephrolithiasis

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

Kidney stones are a common disorder of the urinary tract. Nephrolithiasis is a morbid and expensive disease. The prevalence and incidence are estimated at 5-10% and 100-300/100,000/year, respectively. Relapses occur in 50-70% of all cases. For these reasons, prevention of stone formation is of great importance. Knowing the composition of the calculus is thus fundamental for a more complete evaluation of the metabolic study. The nature of the calculus in fact helps the physician to find a convenient metaphylaxis consisting of both sanitary and therapeutic measures. Study of the composition of urinary stones remains one of the most interesting aspects of the lithiasic pathology today. Presently crystallographic examination constitutes one of the most precise and less expensive methodologies to identify the nature of the concretion. This method also allows the urologist to catalogue the typology of the lithiasis during endoscopy.

Topics: Calcium Oxalate; Calcium Phosphates; Crystallography; Humans; Kidney Calculi; Magnesium Compounds; Nephrolithiasis; Phosphates; Struvite; Uric Acid

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

The goal of this study was to analyze the effect of stone composition on the efficacy of retrograde intrarenal surgery (RIRS) with kidney stones of 1-3 cm, 1-2 cm, and 2-3 cm in diameter.. We undertook a retrospective analysis of 74 patients with kidney stones who underwent RIRS. The patients were divided into two groups based on stone composition: Group I (n=47) (calcium oxalate monohydrate and calcium phosphate) was the hard to fragment stone group and group II (n=27) (calcium oxalate dihydrate, magnesium ammonium phosphate, and uric acid) was the easy to fragment stone group. Forty-six patients with kidney stones 1 to 2 cm in diameter were divided into group A (n=30) (smaller than 20 mm, hard to fragment stones) and group B (n=16) (smaller than 20 mm, easy to fragment stones). Twenty-eight patients with stones 2 to 3 cm in diameter were divided into group C (n=17) (larger than 20 mm, hard to fragment stones) and group D (n=11) (larger than 20 mm, easy-to-crush stones).. The stone clearance rates of group I and group II were 66.0% and 88.9%, respectively (P<0.05). The stone clearance rates of group A and group B were 73.3% and 100% (P<0.05). The stone clearance rates of group C and group D were 52.9% and 72.7%, respectively.. Stone composition has a significant impact on the efficacy of RIRS in the management of 1 to 3 cm kidney stones. For 2-3 cm calcium oxalate dihydrate stones, uric acid stones, and magnesium ammonium phosphate stones, the outcome of RIRS treatment was relatively good, and RIRS is recommended.

Topics: Adult; Calcium Oxalate; Calcium Phosphates; Female; Humans; Kidney; Kidney Calculi; Magnesium Compounds; Male; Middle Aged; Nephrolithiasis; Phosphates; Retrospective Studies; Struvite; Treatment Outcome; Ureteroscopy; Uric Acid

Topics: Animal Feed; Animal Nutrition Sciences; Animal Nutritional Physiological Phenomena; Animals; Calcium Oxalate; Cat Diseases; Cats; Magnesium Compounds; Nephrolithiasis; Phosphates; Prevalence; Struvite; Urolithiasis

To evaluate the influence of acidifying or alkalinizing diets on bone mineral density and urine relative supersaturation (URSS) with calcium oxalate and struvite in healthy cats.. 6 castrated male and 6 spayed female cats.. 3 groups of 4 cats each were fed diets for 12 months that differed only in acidifying or alkalinizing properties (alkalinizing, neutral, and acidifying). Body composition was estimated by use of dual energy x-ray absorptiometry, and 48-hour urine samples were collected for URSS determination.. Urine pH differed significantly among diet groups, with the lowest urine pH values in the acidifying diet group and the highest values in the alkalinizing diet group. Differences were not observed in other variables except urinary ammonia excretion, which was significantly higher in the neutral diet group. Calcium oxalate URSS was highest in the acidifying diet group and lowest in the alkalinizing diet group; struvite URSS was not different among groups. Diet was not significantly associated with bone mineral content or density.. Urinary undersaturation with calcium oxalate was achieved by inducing alkaluria. Feeding an alkalinizing diet was not associated with URSS with struvite. Bone mineral density and calcium content were not adversely affected by diet; therefore, release of calcium from bone caused by feeding an acidifying diet may not occur in healthy cats.

Topics: Absorptiometry, Photon; Animal Feed; Animals; Body Composition; Bone Density; Calcium Oxalate; Cat Diseases; Cats; Diet; Female; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Nephrolithiasis; Phosphates; Struvite

We investigated contents and classes of urinary and stone matrix lipids, and evaluated their clinical relevance in nephrolithiasis patients. Lithogenic role of major lipid classes was explored. Urine (24 h) and stone samples were collected from 47 patients with nephrolithiasis. Control urines were obtained from 29 healthy subjects. Urinary 8-hydroxy-deoxyguanosine (8-OHdG), malondialdehyde (MDA), N-acetyl-β-glucosaminidase (NAG) activity and total proteins were measured. Total lipids were extracted from centrifuged urines (10,000 rpm, 30 min) and stones by chloroform/methanol method. Major classes of lipids were identified using multi-one-dimensional thin-layer chromatography (MOD-TLC). Influence of each lipid class purified from stone matrices on stone formation was evaluated using crystallization and crystal aggregation assays. Urinary NAG activity and 8-OHdG were significantly elevated in nephrolithiasis patients. Total lipids in centrifuged urines of the patients were not significantly different from that of controls. In nephrolithiasis, urinary excretion of total lipids was linearly correlated to urinary MDA, 8-OHdG, NAG activity and total proteins. Lipid contents in stone matrices varied among stone types. Uric acid stone contained lower amount of total lipids than calcium oxalate and magnesium ammonium phosphate stones. MOD-TLC lipid chromatograms of healthy urines, nephrolithiasis urines and stone matrices were obviously different. Triacylglyceride was abundant in urines, but scarcely found in stone matrices. Stone matrices were rich in glycolipids and high-polar lipids (phospholipids/gangliosides). Partially purified glycolipids significantly induced crystal aggregation while cholesterol was a significant inducer of both crystal formation and agglomeration. In conclusion, total lipids in centrifuged urines did not differ between nephrolithiasis and healthy subjects. Our finding suggests that the significant sources of lipids in patients' urine may be large lipids-containing particles, which are removed in centrifuged urines. However, urinary lipid excretion in nephrolithiasis patients was associated with the extent of oxidative stress and renal tubular injury. Triacylglyceride was abundant in urines, but rarely incorporated into stones. Glycolipids were principal lipid constituents in stone matrices and functioned as crystal aggregator. Cholesterol purified from stone matrices bared crystal nucleating and aggregating activities.

Topics: Acidosis, Renal Tubular; Adult; Calcium Oxalate; Chromatography, Thin Layer; Deoxyguanosine; Female; Humans; Lipids; Magnesium Compounds; Male; Malondialdehyde; Middle Aged; Nephrolithiasis; Oxidative Stress; Phosphates; Struvite; Uric Acid; Urinalysis