To explore underlying mechanism of urinary stones formation, the composition and microstructure of urinary stones were analyzed systematically with a large sample study from China. A total of 2437 urinary stones were obtained from the urology department at our Hospital. The composition of the stones was analyzed by Fourier transform infrared spectroscopy (FTIR). Meanwhile, the microstructure and element distribution were observed with scanning electron microscopy combined with element distribution analysis (SEM-EDAX). Urinary stones were classified into eight types, that were consisted of calcium oxalate stones (1301/2437, 53.39%), calcium phosphate stones (131/2437, 5.38%), anhydrous uric acid stones (434/2437, 17.81%), magnesium ammonium phosphate stones (12/2437, 0.49%), sodium urate stones (5/2437, 0.21%), brushite stones (4/2437, 0.16%), cystine stones (3/2437, 0.12%) and mixed stones (547/2437, 22.45%, ten subtypes were included). Under SEM, they displayed distinct microstructures: plank-like, brick-like, polyhedron or paliform crystals for calcium oxalate stones, similar sized echin-sphere or rough bulbiform or tree bark-like crystals for calcium phosphate stones, rotten-wood-like or petrous crystals for anhydrous uric acid stones, globular or gallet-like crystals for magnesium ammonium phosphate stones, sawdust-like crystals for sodium urate stones, broken-wood-like crystals for brushite stones, stacking hexagonal cystine crystals for cystine stones, and two or more of the above crystals for mixed stones. Meanwhile, they also presented distinct elemental composition and distribution by EDAX. Urinary stones can be classified into eight types, and exhibit a diversity of microstructure and elemental compositions in China. The formation process of different types of urinary stones may be diverse.

To provide some basis for the prevention of urinary stones in general population, we did a systemic analysis of urinary stones from Northern, Eastern, Central, Southern and Southwest China by a multi-center study. A total of 11,157 urinary stones from Northern, Eastern, Central, Southern and Southwest China were obtained and analyzed by Fourier transform infrared spectroscopy. Combined with scanning electron microscopy and X-ray energy spectrometer, urinary stones were classified into different types. Furthermore, the correlation between stone types and clinical characteristics, as well as their regional distribution were elucidated. Calcium oxalate stones were the most common type in each region, followed by calcium oxalate-calcium phosphate mixed stones, uric acid stones and calcium phosphate stones. The distribution of calcium oxalate stones were highest prevalence in Southwest China (67.9%, P < 0.05), followed by Eastern and Northern China. Anhydrous uric acid stones, with a constituent ratio of 19.3% in Southern China, and 13.7% in Central China, were significantly higher than that in other regions (P < 0.05). Elements analysis indicated varieties among stone types as well as distribution regions. Moreover, the clinical characteristics were highly correlated with stone types and anatomical locations but not their distribution regions. The material and elements composition of urinary stones among different regions showed some varieties. Calcium oxalate stone has the highest constituent ratio in Southwest China, while anhydrous uric acid stone has the highest constituent ratio in Southern China. Moreover, the clinical characteristics were highly correlated with stone types and anatomical locations but not their distribution regions.

Cystine stones, the main component of which is cystine, are very common urinary calculi, but are rare in the gall bladder. In animals, there has been only one report of cystine gallstones in tree shrews, and to our knowledge, this is the first report of cystine gallstones in humans.

Numerous risk factors are linked to gallbladder stone disease (GBSD). Nonetheless, the relationship between Clonorchis sinensis (C. sinensis) and this condition remains to be clarified. The antibody against C. sinensis in serum and the glucose, triglyceride, and cholesterol levels were investigated in 220 patients with GBSD and 251 controls. Bile components were analysed in patients with gallbladder polyps (GP, n = 18), gallstones (GS, n = 265), and GS combined with C. sinensis infection (GSI, n = 243). Additionally, the gallbladder ejection fraction (%E), residual gallbladder volume (RGV) at 1 h after a fatty meal, and fasting gallbladder volume (FGV) were compared among the GP (n = 43), GS (n = 311), and GSI (n = 277) groups. The results indicated positive antibody against C. sinensis (OR: 1.759, 95% CI: 1.163–2.662) and hyperglycaemia (glucose concentration ≥ 6.10 mmol/L, OR: 2.263, 95% CI: 1.227–4.172) were risk factors for GBSD. There were more non-cholesterol stones in GSI patients (216/241, 89.6%) than in GS patients (137/281, 48.8%) (P < 0.0001). Microscopic observations revealed that mucus containing glycogen coated the C. sinensis eggs and the proportion of dead eggs gradually increased in bile, sediment, and stones alongside rising calcium salt content. Total bile acid and cholesterol concentrations were lower in GSI patients than in GP patients or GS patients (P < 0.05). Moreover, increased FGV and RGV and decreased %E were observed in GSI patients compared with GP patients (P < 0.001). The formation of non-cholesterol gallstones in populations residing in endemic areas is related to the deposition, death, and calcification of eggs in the gallbladder, changes in bile components, and decreased gallbladder motility caused by C. sinensis infection.

Crystals or stones within the gallbladder wall in patients with gallbladder stones (GBS) have been occasionally reported, but their clinical features and aetiology remain unclear. This retrospective study analysed 323 consecutive patients with GBS who underwent rigid choledochoscopic gallbladder-preserving cholecystolithotomy to determine the detection rate, clinical features, and potential risk factors of gallbladder intramural stones (IS). IS were found in 24.1% (78/323) of patients, characterised by distinct cholangioscopic findings, including stone shadows, yellow floating bands, or a combination of both within the gallbladder wall. Compared to patients without IS, those with IS had a higher prevalence of Clonorchis sinensis (C. sinensis) eggs (60.3% vs. 40.8%, P < 0.05) and elevated serum cholesterol, LDL cholesterol, and Apo-B levels (P < 0.05). However, stone composition and C. sinensis egg detection rates did not differ between intraluminal stones and IS within the same patient (P > 0.05). Logistic regression analysis revealed that IS were associated with C. sinensis infection and elevated Apo-B levels. In conclusion, IS share homology with intraluminal stones in the same patient with GBS and exhibit unique appearances in rigid choledochoscopy. For patients with GBS and IS, elevated serum Apo-B levels and C. sinensis infection were independent risk factors.