Amitriptyline eliminates calculi through urinary tract smooth muscle relaxation

Retrospective evaluation of the effect of inhalant anesthesia on complications and recurrence rates in feline urethral obstruction

OBJECTIVES

The aim of this study was to evaluate the use of inhalant anesthesia vs sedation for urinary catheter placement in male cats with urethral obstruction. The primary outcome measures were the incidence of complications related to catheterization, the incidence of recurrent urethral obstruction (rUO; both during hospitalization and within 1 year) and survival. The secondary aim of this study was to evaluate the association between baseline serum biochemical concentrations and antispasmodic medications with complications and short-term rUO.

METHODS

We carried out a retrospective review of records from a university teaching hospital from 2009 to 2020. Cats were included if diagnosed with a urinary obstruction, based on the presence of a large, painful and non-expressible bladder, a urinary catheter was placed and hospitalization occurred for a minimum of 24 h. Collected baseline data included age, breed, weight, serum biochemical concentrations and if cats underwent sedation or inhalant anesthesia for urethral catheterization. For the comparison of inhalant anesthesia or sedation, univariate logistic regression was used.

RESULTS

There was no statistically significant difference in complications or the recurrence of obstruction in cats with urethral obstruction that underwent inhalant anesthesia compared with sedation. All serum biochemical concentrations were significantly associated with survival. Decreased serum ionized calcium was found to be statistically significantly associated with higher complication rates (P = 0.0086), as well as short-term recurrence of obstruction (P = 0.004). Increased serum potassium concentrations were found to be statistically significantly associated with the risk of short-term recurrent urethral obstruction (P = 0.0345). No significant difference was found between the use of antispasmodic medications with short-term recurrence.

CONCLUSIONS AND RELEVANCE

No significant difference was found between complications or recurrence rates when comparing the use of inhalant anesthesia to sedation protocols. Baseline serum biochemical data were significantly associated with complications, survival and short-term recurrence rates.

Case Report: Successful Management and Long-Term Follow-Up of Bilateral Ureteral Ligation in a Dog Secondary to Cryptorchid Castration Utilizing Bilateral Ureteral Stents and a Neoureterocystostomy Procedure

Objective

To report the successful management of the bilateral ureteral obstruction secondary to ureteral ligation during unilateral cryptorchid surgery in a dog with the utilization of bilateral ureteral stent placement and a neoureterocystostomy procedure.

Summary

A 7-month-old male-castrated Weimaraner weighing 30 kg was presented to a university teaching hospital for evaluation of a 4-day history of lethargy, vomiting, and stranguria following exploratory laparotomy for a left-sided unilateral cryptorchid castration. Based on the concurrent presence of severe azotemia and ultrasonographic findings of bilateral hydronephrosis and hydroureter, the dog was diagnosed with the suspected bilateral ureteral obstruction. The dog underwent a laparotomy which revealed bilateral ureteral ligation which was corrected with a left-sided neoureterocystostomy and right-sided retrograde ureteral stent placement. Subsequent placement of a left-sided ureteral stent due to complications with the neoureterocystostomy site was performed later. Ultimately, both ureteral stents were able to be removed a few months later. The dog was clinically doing well with a baseline creatinine of 1.5 mg/dl (132.6 μmol/L) 532 days following initial bilateral ureteral ligation.

New or Unique Information Provided

This case report describes the successful long-term management of iatrogenic bilateral ureteral obstructions in a male dog using a combination of bilateral ureteral stents and neoureterocystostomy.

A stereological study of the effects of antidepressants on postmenopausal rat kidney

Many factors can cause depression including genes (DNA), brain chemistry or stress. Antidepressant drugs affect the brain, heart, liver and kidney. We investigated the effects of the antidepressant drugs, amitriptyline (AMI) and paroxetine (PARO) on kidney. We used 24 adult female rats that were ovariectomized bilaterally 7 days before the experiment. The ovariectomized (OVX) animals and healthy control rats were divided into four equal groups for 4 weeks: control group, OVX control group (sham), AMI group and PARO group. Following the experimental period, the Cavalieri method was applied to sections of the kidney. PARO produced adverse effects on distal and proximal tubule volume, but AMI had no effect on the volume of distal and proximal tubules. Both PARO and AMI decreased the volume of Bowman spaces. PARO also damaged the kidney tubules and cells.

Lipid mediators in diabetic nephropathy

The implications of lipid lowering drugs in the treatment of diabetic nephropathy have been considered. At the same time, the clinical efficacy of lipid lowering drugs has resulted in improvement in the cardiovascular functions of chronic kidney disease (CKD) patients with or without diabetes, but no remarkable improvement has been observed in the kidney outcome. Earlier lipid mediators have been shown to cause accumulative effects in diabetic nephropathy (DN). Here, we attempt to analyze the involvement of lipid mediators in DN. The hyperglycemia-induced overproduction of diacyglycerol (DAG) is one of the causes for the activation of protein kinase C (PKCs), which is responsible for the activation of pathways, including the production of VEGF, TGFβ1, PAI-1, NADPH oxidases, and NFҟB signaling, accelerating the development of DN. Additionally, current studies on the role of ceramide are one of the major fields of study in DN. Researchers have reported excessive ceramide formation in the pathobiological conditions of DN. There is less report on the effect of lipid lowering drugs on the reduction of PKC activation and ceramide synthesis. Regulating PKC activation and ceramide biosynthesis could be a protective measure in the therapeutic potential of DN. Lipid lowering drugs also upregulate anti-fibrotic microRNAs, which could hint at the effects of lipid lowering drugs in DN.

Management of urinary tract emergencies in small animals

This article focuses on some of the most commonly seen urinary tract emergencies in dogs and cats, with emphasis on basic pathophysiology, diagnosis, and emergency management of these cases.

Amitriptyline aggravates the fibrosis process in a rat model of infravesical obstruction

Infravesical obstruction (IVO) secondary to benign prostatic hypertrophy can affect up to 50% of men over 50 years old and may cause serious and irreversible alterations throughout the urinary tract, especially in the bladder. Therapeutic approaches are currently limited. Amitriptyline has recently been described as an analgesic, anti-inflammatory and myorelaxant in some experimental models. The objective of this study was to investigate the effects of amitriptyline hydrochloride on the process of fibrosis in a bladder outlet obstruction model in rats. Male Wistar rats were subjected to IVO and studied at intervals of 1 and 14 days postprocedure. The rats were randomly divided into five groups: sham, IVO1-T, IVO1-NT, IVO14-T and IVO14-NT. Bladder tissue was processed for histopathology, immunohistochemistry and RT-PCR. The IVO14 groups presented bladder fibrosis, smooth muscle cell hypertrophy and bladder wall thickening. The IVO14-T group demonstrated a higher intensity of fibrosis, higher macrophage infiltration rate and higher gene expression of Transforming growth factor (TGF) Tgf-β1. Thus this data shows that in this experimental mode amitriptyline had an amplifying effect on the process of fibrosis as a whole.

Cats and calcium oxalate: strategies for managing lower and upper tract stone disease

PRACTICAL RELEVANCE

Calcium oxalate (CaOx) containing stones are among the most common of the urinary tract stones identified in cats.

RISK FACTORS

Risk factors for CaOx stone formation include such things as breed, gender and diet; stress and obesity have also been hypothesized to be risk factors for this disease.

MANAGEMENT APPROACH

A tailored, individual management strategy for preventing CaOx stone recurrence is important and should include addressing the diet, environment and any other comorbid conditions present. Increasing the cat's moisture intake is one of the key mechanisms for preventing recurrence.

CLINICAL CHALLENGES

CaOx ureterolithiasis has emerged as a difficult and sometimes life-threatening problem for cats. In those cats where stones are found incidentally, periodic monitoring may be required to assess for disease progression. Interventional procedures such as ureteral stent placements are now increasingly being performed for recurrent cases or those with larger stone burdens. Periodic radiographs for more severe cases and frequent client communication can help ensure successful outcomes for cats with lower and upper CaOx stone disease.

EVIDENCE BASE

Limited evidence-based studies are published regarding management of feline upper and lower urinary tract CaOx stone disease, making this a difficult condition to manage in some cats. Studies designed to evaluate the relationship to dietary modifications, medical management, stress, obesity and surgical techniques are warranted in cats with upper and lower urinary tract CaOx stones.

A protocol for managing urethral obstruction in male cats without urethral catheterization

OBJECTIVE

To determine efficacy of a protocol for managing urethral obstruction (UO) in male cats without urethral catheterization.

DESIGN

Clinical trial.

ANIMALS

15 male cats with UO in which conventional treatment had been declined.

PROCEDURES

Laboratory testing and abdominal radiography were performed, and cats with severe metabolic derangements or urinary calculi were excluded. Treatment included administration of acepromazine (0.25 mg, IM, or 2.5 mg, PO, q 8 h), buprenorphine (0.075 mg, PO, q 8 h), and medetomidine (0.1 mg, IM, q 24 h) and decompressive cystocentesis and SC administration of fluids as needed. Cats were placed in a quiet, dark environment to minimize stress. Treatment success was defined as spontaneous urination within 72 hours and subsequent discharge from the hospital.

RESULTS

Treatment was successful in 11 of the 15 cats. In the remaining 4 cats, treatment was considered to have failed because of development of uroabdomen (n=3) or hemoabdomen (1). Cats in which treatment failed had significantly higher serum creatinine concentrations than did cats in which treatment was successful. Necropsy was performed on 3 cats in which treatment had failed. All 3 had severe inflammatory disease of the urinary bladder, but none had evidence of bladder rupture.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that in male cats, a combination of pharmacological treatment, decompressive cystocentesis, and a low-stress environment may allow for resolution of UO without the need for urethral catheterization. This low-cost protocol could serve as an alternative to euthanasia when financial constraints prevent more extensive treatment.

Pleiotropic effects of amitriptyline ameliorate renal fibrosis

Unilateral ureteral obstruction is a well-established model of renal fibrosis used by many investigators to test various compounds for their ability to ameliorate kidney disease. Achar et al. treated ureterally obstructed mice with the tricyclic antidepressant amitriptyline and found that this inhibited inflammation, myofibroblast formation, and several other indices of renal fibrosis. This pleiotropic antidepressant agent appears to have antifibrotic effects in the kidney and other organ systems.

Amitriptyline attenuates interstitial inflammation and ameliorates the progression of renal fibrosis

Amitriptyline is a pleiotropic tricyclic antidepressant, which has anti-oxidant and anti-inflammatory properties. We tested whether amitriptyline might be useful in the treatment of chronic renal disease using the mouse model of unilateral ureteral obstruction. Amitriptyline caused a significant reduction of interstitial fibrosis, determined by Masson's staining, with minimal myofibroblast formation and macrophage infiltration following ureteral obstruction. Using quantitative PCR we found that this treatment significantly reduced the expression of key molecular markers of progressive tubulointerstitial injury such as osteopontin, MCP-1, ICAM-1, and TGF-beta1 compared to their level in a saline-treated control group. Sublethal X-irradiation or mycophenolate mofetil, treatments that reduce inflammation, were comparable to amitriptyline in the reduction of interstitial fibrosis and macrophage infiltration. These studies in animals suggest that amitriptyline is worth testing as a therapeutic agent that might preserve renal function by blocking inflammation and renal fibrosis.

Management of ureteral obstruction due to advanced malignancy: optimizing therapeutic and palliative outcomes

PURPOSE

Treatment of ureteral obstruction due to advanced abdominal or pelvic malignancy is a clinical challenge. We discuss improvements and modern day outcomes in the palliative treatment of patients with ureteral obstruction by antegrade or retrograde ureteral decompression. Also, potential areas of clinical investigation involving ureteral stent improvement and pharmacological management of relief of symptoms resulting from ureteral obstruction are discussed.

MATERIALS AND METHODS

A literature search was performed using the Entrez-PubMed(R) database. All relevant literature on ureteral obstruction, advanced malignancy and nephrostomy, ureteral stent and associated topics concerning palliative care and quality of life were reviewed and analyzed.

RESULTS

Presenting symptoms are varied and depend on the acuity of the underlying problem. Mechanisms underlying the pain and symptoms of extrinsic ureteral compression have not fully been explored but they may include prostaglandin and renin-angiotensin pathways with medical interventions potentially directed at such therapeutic targets. Progressive obstructive uropathy may likely lead to clinical manifestations, such as uremia, electrolyte imbalances and persistent urinary tract infections, if obstruction is not bypassed. New approaches to antegrade and retrograde stenting, and the evaluation of new stent materials may help minimize the complications and side effects of such procedures. Unfortunately the finding of ureteral obstruction due to malignancy carries a poor prognosis with a resulting median survival of 3 to 7 months. This prognosis highlights the importance of maintaining quality of life in these patients.

CONCLUSIONS

Patients presenting with symptoms of ureteral obstruction due to advanced malignancy should be informed of the therapeutic options in the context of the poor prognosis. In the meantime research is needed to find methods of urinary diversion and pharmacological intervention for symptomatic relief without compromising quality of life in patients at the end of life.

Comparison of Mathematic Models for Assessment of Glomerular Filtration Rate with Electron-Beam CT in Pigs

PURPOSE

To prospectively compare in pigs three mathematic models for assessment of glomerular filtration rate (GFR) on electron-beam (EB) computed tomographic (CT) images, with concurrent inulin clearance serving as the reference standard.

MATERIALS AND METHODS

This study was approved by the institutional animal care and use committee. Inulin clearance was measured in nine pigs (18 kidneys) and compared with single-kidney GFR assessed from renal time-attenuation curves (TACs) obtained with EB CT before and after infusion of the vasodilator acetylcholine. CT-derived GFR was calculated with the original and modified Patlak methods and with previously validated extended gamma variate modeling of first-pass cortical TACs. Statistical analysis was performed to assess correlation between CT methods and inulin clearance for estimation of GFR with least-squares regression analysis and Bland-Altman graphical representation. Comparisons within groups were performed with a paired t test.

RESULTS

GFR assessed with the original Patlak method indicated poor correlation with inulin clearance, whereas GFR assessed with the modified Patlak method (P < .001, r = 0.75) and with gamma variate modeling (P < .001, r = 0.79) correlated significantly with inulin clearance and indicated an increase in response to acetylcholine.

CONCLUSION

CT-derived estimates of GFR can be significantly improved by modifications in image analysis methods (eg, use of a cortical region of interest).

Neuronal and smooth muscle receptors involved in the PACAP- and VIP-induced relaxations of the pig urinary bladder neck

BACKGROUND AND PURPOSE

As pituitary adenylate cyclase-activating polypeptide 38 (PACAP 38)- and vasoactive intestinal peptide (VIP) are widely distributed in the urinary tract, the current study investigated the receptors and mechanisms involved in relaxations induced by these peptides in the pig bladder neck.

EXPERIMENTAL APPROACH

Urothelium-denuded strips were suspended in organ baths for isometric force recordings and the relaxations to VIP and PACAP analogues were investigated.

KEY RESULTS

VIP, PACAP 38, PACAP 27 and [Ala(11,22,28)]-VIP produced similar relaxations. Inhibition of neuronal voltage-gated Ca(2+) channels reduced relaxations to PACAP 38 and increased those induced by VIP. Blockade of capsaicin-sensitive primary afferents (CSPA), nitric oxide (NO)-synthase or guanylate cyclase reduced the PACAP 38 relaxations but failed to modify the VIP responses. Inhibition of VIP/PACAP receptors and of voltage-gated K(+) channels reduced PACAP 38 and VIP relaxations, which were not modified by the K(+) channel blockers iberiotoxin, charybdotoxin, apamin or glibenclamide. The phosphodiesterase 4 inhibitor rolipram and the adenylate cyclase activator forskolin produced potent relaxations. Blockade of protein kinase A (PKA) reduced PACAP 38- and VIP-induced relaxations.

CONCLUSIONS AND IMPLICATIONS

PACAP 38 and VIP relax the pig urinary bladder neck through muscle VPAC(2) receptors linked to the cAMP-PKA pathway and involve activation of voltage-gated K(+) channels. Facilitatory PAC(1) receptors located at CSPA and coupled to NO release, and inhibitory VPAC receptors at motor endings are also involved in the relaxations to PACAP 38 and VIP, respectively. VIP/PACAP receptor antagonists could be useful in the therapy of urinary incontinence produced by intrinsic sphincter deficiency.