Thiol/disulphide homeostasis levels in erectile dysfunction patients

Diagnostic work up: Laboratory and biomarkers

This chapter will focus on the diagnostic work around sexual dysfunction in Parkinson's disease, especially laboratory tests and biomarkers. A number of methods to analyze if sexual dysfunction is caused by neural pathology, vascular dysfunction or other mechanisms are now available. Other methods can be used to differentiate between psychogenic/functional reasons behind sexual dysfunction and organic ones. The role of biomarkers for diagnosis, but also for understanding the reason behind and for counteracting sexual dysfunction is becoming more evident. There is also a rich and increasing number of scales and other instruments available for detecting and quantifying sexual hypo- and hyperactivity. When investigating the reason behind sexual dysfunction in patients with Parkinson's disease comorbidities should also be considered. Finally, early and pronounced sexual dysfunction might in some cases be an indication that differential diagnosis, like Multisystem Atrophy, should be thought about. All these aspects of the diagnostic procedures around sexual dysfunction in Parkinson's disease will be covered in this chapter.

Thiol/Disulfide Homeostasis in Patients With Erectile Dysfunction

BACKGROUND

Although there are no sufficient data on association between oxidative stress and erectile dysfunction (ED), numerous studies have reported that imbalance between the formation of reactive oxygen species and body's antioxidant defenses may play a role in the pathogenesis of ED.

AIM

The aim of this study was to determine and compare the oxidant and antioxidant status in patients with ED and healthy controls with a novel automated assay for thiol/disulphide homeostasis test.

METHODS

Our study included 123 patients with ED and 90 healthy individuals. ED was evaluated by asking questions 1-5 and 15 of the International Index of Erectile Function form. In this study, we used Erel and Neselioglu's thiol/disulfide homeostasis test, which is one of the novel methods that can measure both variables of the oxidative/antioxidative balance individually and collectively.

OUTCOMES

This method measured serum antioxidant (total thiol [toSH], native thiol [SH]) and oxidant (disulfide [SS]) levels. The statistical comparisons were performed between patients with ED (ED+ group) and without ED (ED- group) first and then within the ED+ group. After toSH, SH, and SS levels were determined; SS/toSH%, SS/SH%, and SH/toSH% levels were analyzed separately and compared statistically.

RESULTS

We found a significant difference between ED- and ED+ groups in terms of toSH, SH, SS/toSH%, and SS/SH% ratios. SS parameters were increased in patients with ED, but there was no significant difference in terms of SS and SH/toSH% values.

CLINICAL IMPLICATIONS

Clarification of the factors involved in the etiology of ED such as oxidative/antioxidative balance may open new grounds in the early diagnosis and treatment of the disease.

STRENGTHS & LIMITATIONS

It is a prospective, randomized clinical study with the use of a novel, reliable, and fully automated technique. The limitations of the study are use of a subjective tool such as the International Index of Erectile Function, obtaining blood samples from the peripheral vein instead of penile cavernosal tissue, and relatively small sample size.

CONCLUSION

The results of this study showed that thiol/disulfide homeostasis is altered in ED, and this imbalance may be a factor in its pathophysiology. We determined that as ED gets more severe, toSH and SH parameters decrease, whereas SS parameter increases. Micoogullari U, Karatas OF, Kisa E, et al. Thiol/Disulfide Homeostasis in Patients With Erectile Dysfunction. J Sex Med 2020;17:1934-1941.

Evaluation of dynamic thiol-disulphide homeostasis in obstructive uropathy

PURPOSE

To evaluate the ability of thiol-disulphide homeostasis to predict renal injury in ureteral obstruction by matching renal scintigraphy and pathological findings in an experimental rat model.

METHODS

24 rats were randomized and divided into 3 groups as sham, partial and complete. Blood samples for biochemical evaluations and dimercaptosuccinic acid (DMSA) renal scintigraphy were performed at the beginning and on the 7th day postoperatively. Only a midline abdominal incision was done in sham group. Left ureter of partial group was dissected and gently buried into the psoas muscle. In complete group, left ureter was dissected and ligated.

RESULTS

Statistically significant association was found between left kidney function loss percentage, native thiol, total thiol and creatinine alterations and pathological EGTI (Endothelial, Glomerular, Tubular, Interstitial) scores (r = - 0.867, r = - 0.815, r = 0.745, r = - 0.911; p = 0.000). Statistically significant difference was detected between groups in terms of postoperative native thiol and total thiol values (p = 0.000, p = 0.001). There was also a significant difference in preoperative and postoperative comparisons of these parameters in partial and complete obstruction groups (p = 0.012, p = 0.018). There was a significant difference in terms of postoperative disulphide/native thiol and native thiol/total thiol ratios in complete obstruction group compared to other groups (p₁ = 0.011, p₂ = 0.040; p₁ = 0.015, p₂ = 0.028).

CONCLUSIONS

Association with scintigraphic and pathological results empowers the value of this parameter. Disulphide/native thiol and native thiol/total thiol ratios indicate complete obstruction. These findings may shed light to more comprehensive studies.