Formation of struvite urinary stones and approaches towards the inhibition-A review.

BACKGROUND: Struvite is one of the most common urinary/kidney stones, composed of magnesium ammonium phosphate (MgNHPO4·H2O). They are also termed as infection stones as these are associated with urinary tract infections. Numerous studies have been carried out to examine the growth and inhibition of struvite stones. OBJECTIVE: This review summarizes various reports on the factors responsible for inducing struvite stones in the kidney and gives a detailed account of studies on inhibition of growth of struvite crystals. RESULTS: The presence of urea-splitting bacteria such as Proteus mirabilis and alkaline pH plays a crucial role in struvite formation. In vitro inhibition of struvite stones by various chemical agents were examined mainly in artificial urine whereas inhibition by herbal extracts was studied in vitro by gel diffusion technique. Herbal extracts of curcumin, Boerhaavia diffusa Linn, Rotula aquatica and many other plants, as well as some chemicals like pyrophosphate, acetohydroxamic acid, disodium EDTA and trisodium citrate, were reported to successfully inhibit struvite formation. CONCLUSION: The present review recapitulates various factors affecting the growth of struvite urinary stones and the inhibitory role of certain chemicals and herbal extracts. Most of the tested plants are edible hence can be easily consumed without any adverse effects whereas the side effects of chemicals are unknown due to lack of toxicity studies. Thus, the use of herbal extracts might serve as an alternate and safe therapy for prevention of struvite stones.

Combined effects of MSU crystals injection and high fat-diet feeding on the establishment of a gout model in C57BL/6 mice

Abstract Objective: Gout is characterized by inflammatory arthritis with hyperuricaemia and deposition of monosodium urate (MSU) crystals in the joints. Several animal models have been proposed based on MSU crystals injection or high-fat diet feeding; however, neither hyperuricaemia model nor acute gout model can effectively reflect clinical features of gout. This study aimed to assess the effectiveness of a compound gout model induced by the combination of MSU crystals injection and high-fat diet feeding. Methods: The compound gout model was induced by high-fat diet feeding per day and the intraplantar injection of MSU crystals (1 mg) into the footpad of each mouse every 10 days. Serum uric acid, foot swelling and pain analyses were performed at days 22, 32 and 42. Gout inflammation, serum proinflammatory cytokines and gut microbiota analyses were performed only at day 42. Results: Compared to hyperuricaemia model or acute gout model, the compound gout model showed little advantages of elevating serum uric acid, causing foot swelling and gout inflammation, while it caused more severe serum inflammation and gut microbiota dysbiosis. Severe serum inflammation in the compound gout model could be reflected by the increased levels of IL-1 α, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, IFN-γ, KC, MCP-1 and MIP-1β. In addition, the compound gout model induced more alterations in the gut microbiota, including increasing levels of Desulfovibrio and Parasutterella. Conclusion: The injection of MSU and feed of high-fat diet have a combined effect on elevating serum inflammation and causing gut microbiota disorders in the process of establishing a gout model.(AU)