The correlation between demographic factors and upper urinary tract stone composition in the Thai population

The changing composition of urinary calculi in Southern Thailand over the past 14 years

Objective

A worldwide increased incidence of urolithiasis has been observed over the past few decades. Insight into the composition of these stones can lead to enhanced medical treatment and outcomes. The objective of this study was to examine the distribution and chemical composition of urinary calculi in Southern Thailand over the past decade.

Materials and Methods

An analysis was conducted on 2611 urinary calculi submitted to the Stone Analysis Laboratory, Songklanagarind Hospital, a single stone analysis laboratory in Southern Thailand. The analysis was performed from 2007 to 2020 using Fourier-transform infrared spectroscopy. The demographic results were described using descriptive statistical analyses, and the Chi-square test for trends was performed to identify changes in urinary calculi composition.

Results

The patients' demographic data revealed a male-to-female ratio of 2.2:1; the most common age group of affected men was 50-69 years, whereas the most common age group of affected women was 40-59 years. The most common components found in the calculi were uric acid (30.6%), mixed calcium oxalate with calcium phosphate (29.2%), and calcium oxalate (26.7%). We noted a trend of increasing uric acid calculi for 14 years (P = 0.00493), whereas the trend for the other major components was decreasing.

Conclusion

The most common component of urinary calculi analyzed in Southern Thailand was uric acid, with a significant rising trend in proportion in the past decade; the trend of other major components, such as mixed calcium oxalate-calcium phosphate and calcium oxalate, decreased.

Consumption of soft drinks rich in phosphoric acid versus struvite crystallization from artificial urine

In recent years, there has been a continuous increase in the incidence of urolithiasis, especially in highly developed countries. Therefore, the question arises which factors specific to these countries may be responsible for the increase in the incidence of this disease. In this article, we try to assess the effect of phosphoric acid, a component of various carbonated drinks, including Coca-Cola, on the nucleation and growth of struvite crystals, which are the main component of infectious urinary stones. The research was carried out in the environment of artificial urine with and without the presence of Proteus mirabilis bacteria. In the latter case, the activity of bacterial urease was simulated by adding an aqueous ammonia solution. The obtained results indicate that phosphoric acid present in artificial urine causes the nucleation of struvite to shift towards a lower pH, which means that struvite nucleates earlier in artificial urine compared to the control test. The amount of struvite formed is the greater the higher the concentration of phosphoric acid. At the same time, as the concentration of phosphoric acid increases, the growing struvite crystals are larger, which is disadvantageous because they are more difficult to remove from the urinary tract along with the urine. For the highest levels of phosphoric acid tested, large dendrites are formed, which are particularly undesirable as they can damage the epithelium of the urinary tract. The effect of phosphoric acid on the nucleation and growth of struvite is explained in base of chemical speciation analysis. This analysis indicates that the MgHCit and MgCit^- complexes have the main influence on the nucleation and growth of struvite in artificial urine in the presence of phosphoric acid. It should be keep in mind that all these effects of phosphoric acid are possible when the urinary tract is infected with urease-positive bacteria. In the absence of infection, phosphoric acid will not cause struvite to crystallize.

Increased Sulfation in Gracilaria fisheri Sulfated Galactans Enhances Antioxidant and Antiurolithiatic Activities and Protects HK-2 Cell Death Induced by Sodium Oxalate

Urolithiasis is a common urological disease characterized by the presence of a stone anywhere along the urinary tract. The major component of such stones is calcium oxalate, and reactive oxygen species act as an essential mediator of calcium oxalate crystallization. Previous studies have demonstrated the antioxidant and antiurolithiatic activities of sulfated polysaccharides. In this study, native sulfated galactans (N-SGs) with a molecular weight of 217.4 kDa from Gracilaria fisheri were modified to obtain lower molecular weight SG (L-SG) and also subjected to sulfation SG (S-SG). The in vitro antioxidant and antiurolithiatic activities of the modified substances and their ability to protect against sodium oxalate-induced renal tubular (HK-2) cell death were investigated. The results revealed that S-SG showed more pronounced antioxidant activities (DPPH and O₂^- scavenging activities) than those of other compounds. S-SG exhibited the highest antiurolithiatic activity in terms of nucleation and aggregation, as well as crystal morphology and size. Moreover, S-SG showed improved cell survival and increased anti-apoptotic BCL-2 protein in HK-2 cells treated with sodium oxalate. Our findings highlight the potential application of S-SG in the functional food and pharmaceutical industries.