Bozkurt A et al, 2018: Does extracorporeal shockwave lithotripsy therapy affect thiol-disulfide homeostasis?
Bozkurt A, Mertoglu C, Karabakan M, Siranli G, Yurt EF, Erel O.
Department of Clinical Biochemistry, Faculty of Medicine, Department of Urology, Erzincan University, Erzincan, Turkey.
Department of Clinical Biochemistry, Faculty of Medicine, Yildirim Beyazit University, Ankara, Turkey.
Objective: Extracorporeal Shockwave Lithotripsy (ESWL) is a non-invasive method that is effective at crushing stones in the upper urinary tract. Disturbance of the thiol/disulfide homeostasis, in favor of the disulfide, has been shown to be involved in the disease pathogenesis.
Methods: A total of 36 individuals that underwent ESWL had blood samples collected before ESWL (0hrs), 6hrs, and one week after the ESWL. Sera native and total as wells as disulfide amount was measured using an automated method sodium borohydrate (NaBH4) reduction. In addition, Ischemia Modified Albumin (IMA) levels were measured using colorimetric assay method.
Results: Native thiol level was reduced at the 6th hour following ESWL compared to baseline. While the ratios of disulfide level, Disulfide/Total Thiol (DTT), Disulfide/Native Thiol (DNT) and IMA level were increased at the 6th hour following ESWL compared to baseline, they were found to be similar with their baseline values at the end of 1st week. Total thiol and native /total thiol did not show any significant change.
Conclusions: ESWL treatment disrupts thiol/disulfide homeostasis and the structure of albumin at the acute term. Therefore, it increases protein oxidation and leads to increased oxidative stress. However, this state is transient and returns to normal within the proceeding days.
Pak J Med Sci. 2018 Sep-Oct;34(5):1070-1075. doi: 10.12669/pjms.345.15823. FREE ARTICLE
This article deals with the disturbed thiol/disulfide balance following SWL. The conclusion of the study was that increments in disulfide and ratios disulfide/total thiol were recorded 6h after SWL, but these variables were subsequently normalized as demonstrated after 7 days. Native thiol concentrations were reduced. Generally the alterations were discrete and their clinical relevance difficult to prove. The demonstrated effects indicate increased oxidative stress.
Oxidative stress is considered as an important factor for kidney injuries. One of the fundamental factors in this process is thought to be the increased formation of IMH (ischemia modified albumin), but the recorded findings as a consequence of SWL obviously had little clinical significance.
The role of oxidative stress has a more general importance both for stone formation and several other pathological conditions. The plasma concentrations of native thiol, disulfide and disulfide/total thiol shown in the present report were lower than those reported by others .
For urologists with limited biochemical interest (and they are many…); below follows a brief summary of the thiol/disulfide concept obtained from the review in reference :
Thiol is a component containing R-SH-groups, present for instance in amino acids, cysteine, peptides and proteins. Following a redox reaction there is a conversion to R-SS-R groups:
2 R-SH = R-SS-R + 2 e- + 2 H+
Thiol-pools have anti-oxidative properties and thiols accordingly serve as intracellular redox buffers. Anti-oxidants in plasma such as ascorbic acid and uric acid (water soluble) and - and -tocopherol, lycopene, ubiquinol and carotenoider (lipid soluble) are of great importance for maintaining the balance.
It is mentioned that uric acid in plasma is responsible for ~60% of the free radical scavenging capacity. Oxidative effects and thiol modification reflect the role of thiol/disulfide balance in pathological conditions such as diabetes, cardiovascular diseases, rheumatoid arthritis, chronic kidney disease, AIDS, Parkinson’s disease, MS, ALS and Alzheimer’s disease to mention some examples.
In stone disease disturbed balance between thiol and disulfides might be important in the stone forming process, but for possible kidney injuries after SWL obviously very little.
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