Current and emerging pharmacological targets for medical expulsive therapy

Potential clinical applications of current and future oral forms of desmopressin (Review)

Desmopressin is a synthetic analogue of vasopressin and a selective vasopressin receptor 2 agonist. It was first synthesised in 1967 and utilised for its antidiuretic properties. It is also used in bleeding disorders to enhance clotting. Other potential uses of the drug have been reported. The present review aims to provide a broad overview of the literature on potential further uses of oral forms of desmopressin. Key therapeutic areas of interest were identified based on known physiological activities/targets of desmopressin or reports of an effect of desmopressin in the literature. The feasibility of adequate dosing with oral forms of the drug was also considered. Systematic literature searches were carried out using the silvi.ai software for the identified areas, and summaries of available papers were included in tables and discussed. The results of the searches showed that desmopressin has been investigated for its efficacy in a number of areas, including bleeding control, renal colic, the central nervous system and oncology. Evidence suggests that oral desmopressin may have the potential to be of clinical benefit for renal colic and bleeding control in particular. However, further research is needed to clarify its effect in these areas, including randomised controlled studies and studies specifically of oral formulations (and doses). Further research may also yield findings for cancer, cognition and overactive bladder.

Effects of the Surgical Ligation of the Ureter in Different Locations on the Kidney over Time in the Rat Model

Purpose

To evaluate the effects of the surgical ligation of the ureter in different locations on the kidney over time in the rat model.

Methods

A total of 155 rats were enrolled and randomly divided into the case (n = 150) and control (n = 5) groups. The case group included three separate groups (fifty rats in each group) that underwent surgical ureteral ligation at the proximal, middle, and distal ureter. The laboratory tests, and tumor necrosis factor α (TNF-α), were measured in groups. The pathological evaluation for glomerular changes, tubular dilation, interstitial fibrosis, and interstitial infiltration of the inflammatory cells following the obstruction was performed (severity of tubular atrophy categorized too mild (+), moderate (++), and severe (+++)). To compare the continuous variables between the groups and between the measurement times, the analysis of variance (ANOVA) was used.

Results

Our results revealed that the creatinine four weeks after the obstruction was significantly higher in the proximal group obstruction (p value: 0.046). The three groups had no significant differences regarding urine creatinine, serum sodium, and serum TNF (p value: 0.261). Obstruction did not change the glomerular morphology in three intervention groups after six weeks. The commencing of severe tubular atrophy in proximal, middle, and distal ureteral obstruction was at weeks three, four, and six, respectively.

Conclusion

The location of ureteral obstruction is also crucial in deciding to intervene to relieve the complete ureteral obstruction. Severe tubular damage occurs in weeks three, four, and six in proximal, middle, and distal ureteral obstruction, respectively.

Optimal duration of medical expulsive therapy for lower ureteral stones: a critical evaluation

To evaluate the optimal duration of Medical Expulsive Therapy (MET) application for distal ureteric stones on a time period based manner. 89 patients with 5-10 mm distal ureter stones received tamsulosin (0.4 mg) for MET and diclofenac sodium (75 mg) for analgesia. Patients were evaluated once a week for 4 weeks. Radiologic stone passage was evaluated by kidney ureter bladder (KUB) and ultasonography where non-contrast computed tomography (NCCT) was also performed if needed. While 23 cases (28.4%) were SF after first week, 23 were SF (28.4%) after 2 weeks, 9 cases (11.1%) after 3 and lastly 7 cases (8.6%) became SF after four weeks. Nineteen (23.5%) cases were not SF after 4 weeks. A positive relationship was found between the time period elapsed for stone passage and ureteral wall thickness (UWT) along with the degree of hydronephrosis. In addition, mean number of renal colics and emergency department (ED) visits were found to be higher in patients passing stones in the 4th week along with the ones who could not despite MET. SFR for distal ureteric stones sizing 5-10 mm was higher within the first 3 weeks under MET application. Thus, waiting for a longer period of time may result in increased analgesic and unnecessary MET treatment with increased risk of emergency department visits and additional costs as well. We believe that other options could be considered in such cases who are not SF at the end of the first 3 weeks.

Development of a new scoring system predicting medical expulsive therapy success on 4-10 mm distal ureteral stones: medical expulsive therapy stone score (METSS)

Ureteral stone passage by using medical expulsive therapy (MET) are affected by numerous radiological and clinical parameters. We aimed to construct a scoring system, which would be based on clinical and computed tomography (CT)-derived data, to predict the success of the MET approach. 186 patients presenting to urology clinic or emergency department with unilateral single 4-10 mm distal ureteral stone and who had MET were included. All patients were divided into two groups as the MET-successful group and the MET-unsuccessful group. The success rate of MET was 67.2%. Stone size ≥ 6.5 mm, stone density > 1078 HU, ureteral wall thickness (UWT) > 2.31 mm, ureteral diameter (UD) > 9.24 mm, presence of periureteral stranding (PUS) and presence of diabetes mellitus (DM) were stated as the independent risk factors. Based on the regression coefficients on multivariate logistic regression analysis, 1 point for stone size > 6.5 mm, 2 points for stone density > 1078 HU, 2 points for UWT > 2.31 mm, 3 points for UD > 9.24 mm, 1 point for presence of PUS and 1 point for presence of DM were assigned to patients for each risk factor. Higher medical expulsive therapy stone score (METSS) indicated lower MET success. All patients were classified into three risk groups according to METSS: low risk (0-3 points; success percentage: 92.8%); intermediate risk (4-5 points; success percentage: 60.4%) and high risk (6-10 points; success percentage: 8.3%). The METSS seems to separate successfully the patients with a favorable or adverse constellation of factors.

The enhancing effect of 5-HT on phasic contractions of human isolated distal ureter and the mechanisms mediating these effects

5-Hydroxytryptamine (5-HT) can enhance human ureteral contractions. However, the mediating receptors have not been clarified. This study sought to further characterize the mediating receptors using several selective antagonists and agonists. Human distal ureters were obtained from 92 patients undergoing cystectomy. The mRNA expression levels of 5-HT receptors were examined using RT-qPCR experiments. The phasic contractions of ureter strips, either spontaneous or evoked with neurokinin, were recorded in an organ bath. Among the 13 5-HT receptors, 5-HT_2A and 5-HT_2C receptors showed the highest mRNA expression levels. 5-HT (10-7-10-4 M) increased the frequency and baseline tension of phasic contractions in a concentration-dependent manner. However, a desensitization effect was observed. The 5-HT_2C receptor selective antagonist, SB242084 (10,30,100nM), shifted the 5-HT concentration-response curves (frequency and baseline tension) rightward with a pA2 value of 8.05 and 7.75, respectively. 5-HT_2C receptor selective agonist, vabicaserin, increased contraction frequency with an Emax of 35% of 5-HT. 5-HT_2A receptor selective antagonist, volinanserin (1,10,100 nM), only reduced baseline tension with a pA2 of 8.18. The selective antagonists of 5-HT_1A,1B, 1D, 2B, 3, 4, 5, 6, and 7 had no antagonism. Blockade of voltage-gated sodium channels, α1-adrenergic receptors, adrenergic neurotransmission, and neurokinin-2 receptors using tetrodotoxin, tamsulosin, guanethidine, and Men10376, respectively, and desensitization of sensory afferents using capsaicin (100 μM), significantly reduced 5-HT effects. We conclude that 5-HT enhanced ureteral phasic contractions mainly by activating 5-HT_2C and 5-HT_2A receptors. Sympathetic nerve and sensory afferents partly contributed to 5-HT effects. 5-HT_2C and 5-HT_2A receptors could be promising targets for ureteral stone expulsion.