Kidney stones

Abstract

Kidney stones are mineral deposits in the renal calyces and pelvis that are found free or attached to the renal papillae. They contain crystalline and organic components and are formed when the urine becomes supersaturated with respect to a mineral. Calcium oxalate is the main constituent of most stones, many of which form on a foundation of calcium phosphate called Randall’s plaques, which are present on the renal papillary surface. Stone formation is highly prevalent, with rates of up to 14.8% and increasing, and a recurrence rate of up to 50% within the first 5 years of the initial stone episode. Obesity, diabetes, hypertension and metabolic syndrome are considered risk factors for stone formation, which, in turn, can lead to hypertension, chronic kidney disease and end-stage renal disease. Management of symptomatic kidney stones has evolved from open surgical lithotomy to minimally invasive endourological treatments leading to a reduction in patient morbidity, improved stone-free rates and better quality of life. Prevention of recurrence requires behavioural and nutritional interventions, as well as pharmacological treatments that are specific for the type of stone. There is a great need for recurrence prevention that requires a better understanding of the mechanisms involved in stone formation to facilitate the development of more-effective drugs.

Pathogenesis of calcium oxalate urinary stone disease: species comparison of humans, dogs, and cats

“…Calcium oxalate kidney stones are more common in men [2, 3], although this gender gap is declining as kidney stones are being diagnosed more often in women [10]. Higher ambient temperature and sunlight indices are independently related to stone prevalence, indicating that geography and environment play a role in kidney stone risk [23].…”

“…Although a variety of underlying diseases can lead to calcium oxalate nephrolithiasis, most cases are idiopathic and are associated with Randall’s plaques [9]. Randall’s plaques are subepithelial calcium phosphate deposits that breach the renal papillary urothelium and lead to calcium oxalate crystallization and stone formation [10]. …”

Histological aspects of the “fixed-particle” model of stone formation: animal studies

“…Kidney stones are mineral concretions found in the renal calyces and pelvis, either free or attached to the renal papillae [4]. The attachment is achieved through sub-epithelial plaques, (Randall’s plaques) present on the papillary surfaces, or crystal plugs (Randall’s plugs), clogging the openings of the ducts of Bellini [4-6].…”

“…The attachment is achieved through sub-epithelial plaques, (Randall’s plaques) present on the papillary surfaces, or crystal plugs (Randall’s plugs), clogging the openings of the ducts of Bellini [4-6]. Randall’s plaques are interstitial deposits of apatitic CaP crystals and are seen in stone formers with idiopathic CaOx, brushite, primary hyperparathyroid, small bowel resection, ileostomy stone disease [7].…”

“…D . Higher magnification images showing membrane bound vesicles and concentrically laminated spherical entities (black arrows) reminiscent of deposits in the Randall’s plaques [4,8,14]. C, Bar=2µm; D, Bar=1µm…”