Urodynamic measurements by radiotelemetry in conscious, freely moving beagle dogs

Human primary muscle stem cells regenerate injured urethral sphincter in athymic rats

Background

The aim of the study was to demonstrate the efficacy of human muscle stem cells (MuSCs) isolated using innovative technology in restoring internal urinary sphincter function in a preclinical animal model.

Methods

Colonies of pure human MuSCs were obtained from muscle biopsy specimens. Athymic rats were subjected to internal urethral sphincter damage by electrocauterization. Five days after injury, 2 × 10⁵ muscle stem cells or medium as control were injected into the area of sphincter damage (n = 5 in each group). Peak bladder pressure and rise in pressure were chosen as outcome measures. To repeatedly obtain the necessary pressure values, telemetry sensors had been implanted into the rat bladders 10 days prior to injury.

Results

There was a highly significant improvement in the ability to build up peak pressure as well as a pressure rise in animals that had received muscle stem cells as compared to control (p = 0.007) 3 weeks after the cells had been injected. Only minimal histologic evidence of scarring was observed in treated rats.

Conclusion

Primary human muscle stem cells obtained using innovative technology functionally restore internal urethral sphincter function after injury. Translation into use in clinical settings is foreseeable.

Collagen/heparin sulfate scaffold combined with mesenchymal stem cells treatment for canines with spinal cord injury: A pilot feasibility study

BACKGROUND

Due to endogenous neuronal deficiency and glial scar formation, spinal cord injury (SCI) often leads to irreversible neurological loss. Accumulating evidence has shown that a suitable scaffold has important value for promoting nerve regeneration after SCI. Collagen/heparin sulfate scaffold (CHSS) has shown effect for guiding axonal regeneration and decreasing glial scar deposition after SCI. The current research aimed to evaluate the utility of the CHSSs adsorbed with mesenchymal stem cells (MSCs) on nerve regeneration, and functional recovery after acute complete SCI.

METHODS

CHSSs were prepared, and evaluated for biocompatibility. The CHSSs adsorbed with MSCs were transplanted into these canines with complete SCI.

RESULTS

We observed that MSCs had good biocompatibility with CHSSs. In complete transverse SCI models, the implantation of CHSS co-cultured with MSCs exhibited significant improvement in locomotion, motor evoked potential, magnetic resonance imaging, diffusion tensor imaging, and urodynamic parameters. Meanwhile, nerve fibers were markedly improved in the CHSS adsorbed with MSCs group. Moreover, we observed that the implantation of CHSS combined with MSCs modulated inflammatory cytokine levels.

CONCLUSIONS

The results preliminarily demonstrated that the transplantation of MSCs on a CHSS could improve the recovery of motor function after SCI. Thus, implanting the MSCs-laden CHSS is a promising combinatorial therapy for treatment in acute SCI.

Use of a bipolar sealing device to seal partial cystectomy with and without augmentation with a single-layer simple continuous suture pattern in an ex vivo canine model

OBJECTIVE

To evaluate the ability of a bipolar sealing device (BSD) to seal canine bladder tissue and to determine the influence of suture augmentation on resistance to leakage of sealed partial cystectomies.

STUDY DESIGN

Ex vivo, simple randomized study.

SAMPLE POPULATION

Urinary bladders harvested from canine cadavers (n = 23).

METHODS

Partial cystectomy of the cranial third of each bladder was performed with a BSD. This seal was augmented with a simple continuous pattern of 4-0 polydioxanone in half of the specimens. A pressure transducer inserted through the ureter measured intraluminal pressure at initial leakage and catastrophic failure as dyed saline was infused via a catheter inserted through the urethra. Initial leakage pressure and pressure at catastrophic failure were compared between sutured and nonsutured sealed partial cystectomies.

RESULTS

Sutured sealed cystectomies showed initial leakage at lower pressures compared to non-sutured cystectomies (8.6 vs. 17.7 mm Hg; P = .0365) but were able to sustain greater pressures at catastrophic failure (34.3 vs. 21.8 mm Hg; P = .007). Catastrophic failure occurred along the seam of all nonsutured sealed cystectomies and at the suture holes in 10 of the 12 sutured bladders.

CONCLUSION

Partial cystectomies were effectively sealed with a BSD in this canine cadaveric bladder model. Augmentation with a simple continuous suture pattern increased the pressure at which catastrophic leakage occurred but lowered initial leak pressure.

CLINICAL SIGNIFICANCE

This study provides evidence supporting the evaluation of BSD use for partial cystectomy in live animals.

Bladder telemetry: A new approach to evaluate micturition behavior under physiological and inflammatory conditions

AIMS

To establish a new approach to cystometry using telemetry in conscious rats and to use this technique to determine the role of conscious decision making processes with respect to the initiation of voiding in physiological, inflammatory, and painful conditions.

METHODS

The pressure transducer of a telemetric transmitter was implanted in the dome of the urinary bladder. After a recovery period of at least 1 month, several investigations of urodynamic parameters were performed after diuresis activation by a pulse of furosemide. The model was characterized by tolterodine and mirabegron under physiological conditions and same animals were reused to evaluate the modification of the voiding pattern under bladder inflammation induced by cyclophosphamide.

RESULTS

The quality of traces and measurement of parameters recorded telemetrically were comparable to those with conventional cystometry. Furosemide induced a reproducible transient increase of urine production and a series of voids that persisted for 60 min. Tolterodine reduced the amplitude of micturition contractions although mirabegron was devoid of any effect. Seven hours after injection of CYP, voiding frequency increased significantly and the micturition amplitude contraction was not altered. However, the mean volume voided during individual micturitions and the total voided volume decreased. During a second exposure to furosemide 24H after CYP injection, the micturition pattern returned to control, however, the micturition volume was still lower than in control.

CONCLUSION

This telemetric model appears to be as accurate as previously described in conscious conventional cystometry, and allows the repeated evaluation of compounds which may modulate the voiding patterns. Neurourol. Urodynam. 36:308-315, 2017. © 2016 The Authors. Neurourology and Urodynamics published by Wiley Periodicals, Inc.

Urodynamic investigation by telemetry in Beagle dogs: validation and effects of oral administration of current urological drugs: a pilot study

Background

Vesico-urethral function may be evaluated in humans and dogs by conventional urodynamic testing (cystometry and urethral pressure profilometry) or by electromyography. These techniques are performed under general anaesthesia in dogs. However, anaesthesia can depress bladder and urethral pressures and inhibit the micturition reflex. The primary objective of this pilot study was to evaluate the use of telemetry for urodynamic investigation in dogs. We also aimed to determine the applicability of telemetry to toxicologic studies by assessing the repeatability of telemetric recordings.

Results

Conventional diuresis cystometry was performed in six continent adult female Beagle dogs prior to surgical implantation of telemetric and electromyographic devices. In the first phase of the telemetric study, continuous recordings were performed over 8 days and nights. Abdominal, intravesical and detrusor threshold pressures (Pdet th), voided volume (Vv), urethral smooth muscle electrical activity and involuntary detrusor contractions (IDC) were measured during the bladder filling phase and during micturition episodes.

Vv recorded during telemetry was significantly lower than bladder volume obtained by diuresis cystometry. Repeatability of telemetric measurements was greater for observations recorded at night. IDC frequency and Pdet th were both lower and Vv was higher at night compared to values recorded during daytime.

In the second phase of the telemetric study, phenylpropanolamine, oestriol, bethanechol, oxybutynin or duloxetine were administered orally for 15 days. For each drug, continuous recordings were performed overnight for 12 hours on days 0, 1, 8 and 15. Electromyographic urethral activity was significantly increased 8 days after oestriol or duloxetine administration. No significant changes in bladder function were observed at any time point.

Conclusions

In dogs, the high repeatability of nocturnal telemetric recordings indicates that this technique could provide more informative results for urologic research. Urethral smooth muscle electrical activity appears to be modified by administration of drugs with urethral tropism. In this pilot telemetric study, bladder function was not affected by oral administration of urological drugs at their recommended clinical dosages. Experimental studies, (pharmacokinetic and pharmacodynamic) and clinical studies are warranted to further define the effects of these drugs on vesico-urethral function in dogs.

Cardiac effects of muscarinic receptor antagonists used for voiding dysfunction

Antimuscarinic agents are the main drugs used to treat patients with the overactive bladder (OAB) syndrome, defined as urgency, with or without urgency incontinence, usually with increased daytime frequency and nocturia. Since the treatment is not curative and since OAB is a chronic disease, treatment may be life-long. Antimuscarinics are generally considered to be ‘safe’ drugs, but among the more serious concerns related to their use is the risk of cardiac adverse effects, particularly increases in heart rate (HR) and QT prolongation and induction of polymorphic ventricular tachycardia (torsade de pointes). An elevated resting HR has been linked to overall increased morbidity and mortality, particularly in patients with cardiovascular diseases. QT prolongation and its consequences are not related to blockade of muscarinic receptors, but rather linked to inhibition of the hERG potassium channel in the heart. However, experience with terodiline, an antimuscarinic drug causing torsade de pointes in patients, has placed the whole drug class under scrutiny. The potential of the different antimuscarinic agents to increase HR and/or prolong the QT time has not been extensively explored for all agents in clinical use. Differences between drugs cannot be excluded, but risk assessments based on available evidence are not possible.

Effect of estrogen and progesterone on urodynamics in the conscious rat

OBJECTIVES

To examine the effects of estrogen and/or progesterone on the cystometric profiles obtained using continuous-filling cystometry in the conscious Sprague-Dawley rat.

METHODS

Sprague-Dawley rats underwent ovariectomy (OVX) and were compared with controls by conscious continuous-filling cystometry. The effect of estrogen (10 microg/kg/d for 14 days) and/or progesterone (10 mg/kg/d for 14 days) replacement on OVX urodynamics was examined (n = 7-8/group).

RESULTS

OVX rats demonstrated reduced micturition intervals and voided volumes compared with controls. These effects of OVX were reversed by estrogen replacement, but not by progesterone replacement. When combined with estrogen, progesterone functioned to partially antagonize the effects of estrogen in OVX rats.

CONCLUSIONS

Estrogen enhances bladder capacity in the OVX rat and therefore is a likely contributor to the larger bladder capacity in the female compared with the male rat. Consistent with its established role in reproductive physiology, progesterone antagonizes the beneficial effects of estrogen on OVX rat urodynamics.

Dual modulation of urinary bladder activity and urine flow by prostanoid EP3 receptors in the conscious rat

BACKGROUND AND PURPOSE

Cyclooxygenase inhibitors function to reduce levels of prostaglandin E(2) (PGE(2)) and are broadly efficacious in models of bladder overactivity. We therefore investigated a regulation of urinary bladder function in conscious rats by modulation of the EP(3) receptor for PGE(2).

EXPERIMENTAL APPROACH

The activity of the EP(3) receptor agonist GR63799X, and EP(3) receptor antagonists, CM9 and DG041, at recombinant EP(3) receptors was evaluated in vitro. In vivo, intraduodenal dosing during conscious, continuous-filling cystometry of spontaneously hypertensive rats was utilized to determine the urodynamic effect of EP(3) receptor modulation.

KEY RESULTS

GR63799X dose-dependently (0.001-1 mg x kg(-1)) reduced bladder capacity, as indicated by a reduction in both the micturition interval and volume of urine per void. In contrast, CM9 (10 and 30 mg x kg(-1)) and DG041 (30 mg x kg(-1)) enhanced bladder capacity, as indicated by significantly longer micturition intervals and larger void volumes. CM9 and DG041 inhibited the responses to GR63799X supporting the in vivo activity of these pharmacological agents at the EP(3) receptor. In addition to its effect on bladder capacity, GR63799X increased endogenous urine production. Intra-arterial infusion of saline mimicked the enhancement of urine flow observed with GR63799X, and the response was inhibited by CM9.

CONCLUSIONS AND IMPLICATIONS

These data support the EP(3) receptor as a modulator of urinary bladder activity in the conscious rat, and in addition, indicate a role for EP(3) receptor activity in regulating urine flow.