Quantitative assessment of urethral vascularity in nulliparous females using high-frequency endovaginal ultrasonography

Correlation analysis of selected anatomical and functional parameters of the urethra, assessed through ultrasound and urodynamic examinations

Aim

This study aimed to examine the correlations between specific urethral function parameters observed in urodynamic testing and selected urethral characteristics evaluated by pelvic floor ultrasonography. Additionally, the presence of urethral funneling during straining was evaluated in female patients referred for surgical treatment of stress urinary incontinence.

Material and methods

A retrospective study was conducted on 192 female patients referred for surgical treatment of stress urinary incontinence with the use of retropubic tension-free vaginal tape. Maximum urethral closure pressure and functional urethral length were evaluated urodynamically during resting profilometry. Ultrasound measurements, along with the assessment of funneling, were performed as part of the pelvic floor examination, following the technique described by Kociszewski. Patients with clinically significant pelvic organ prolapse, a history of anterior compartment surgery, prior radiotherapy, or symptoms of overactive bladder were excluded from the analysis.

Results

The values obtained from urodynamic and ultrasound examinations were evaluated statistically. No correlation was identified between the analyzed urodynamic and ultrasound parameters. Long urethral funneling was confirmed in all patients with stress urinary incontinence assessed as eligible for the placement of tension-free vaginal tape.

Conclusions

The results indicate that urodynamic and ultrasound examinations assess distinct aspects of urethral anatomy and function, and therefore their findings cannot be used interchangeably. Long urethral funneling assessed during pelvic floor ultrasonography was noted in all patients with clinically and urodynamically confirmed stress urinary incontinence.

The SDF-1/CXCR4 axis is involved in adipose-derived stem cell migration

BACKGROUND

Intravenous injection of adipose-derived stem cells (ADSCs) can improve the urinary function of stress urinary incontinence (SUI) model rats and C-X-C chemokine receptor type 4 (CXCR4)-positive ADSCs are found in urethral tissues. The CXCR4 ligand stromal cell-derived factor-1 (SDF-1) is highly expressed in urinary incontinence model rats. In this study, we investigated the involvement of the SDF-1/CXCR4 axis in the homing of ADSCs.

METHODS

ADSCs were isolated from rats and purified. The levels of CXCR4 and CXCR7 were determined by western blot analysis and immunofluorescence assays following stimulation with SDF-1. Hypoxia conditioning was performed to treat the cells in vitro, following which the messenger RNA (mRNA) and protein level of SDF-1, CXCR4, and CXCR7 were estimated.

RESULTS

We found that CXCR4 and CXCR7 were expressed in ADSCs at passage zero (P0), P1, and P3, and the expression of both increased after SDF-1 stimulation. The level of expression of the mRNAs and proteins of SDF-1, CXCR4, and CXCR7 in ADSCs was higher after hypoxic conditioning. We then knocked down CXCR4 or CXCR7 using small interfering RNAs and found that the mRNA levels of CXCR4 and CXCR7 were considerably downregulated in the si-CXCR4/7-transfected cells. We also found that the SDF-1/CXCR4 axis was required for the migration of ADSCs. The phosphorylation levels of Janus kinase (JAK), protein kinase B (AKT), and extracellular regulated protein kinase significantly increased in SDF-1-stimulated ADSCs. However, the migration of ADSCs was suppressed when the corresponding specific inhibitors were used to block JAK and AKT signaling or silence CXCR4, whereas no significant change was observed in the migratory ability of ADSCs when the ERK pathway was blocked or CXCR7 was silenced.

CONCLUSIONS

The SDF-1/CXCR4 axis is involved in the migration of ADSCs and may play a role in the migrate of ADSCs in SUI.

Analysis of urethral blood flow by high-resolution laser speckle contrast imaging in a rat model of vaginal distension

OBJECTIVE

To investigate the feasibility of laser speckle contrast imaging (LSCI) for monitoring urethral blood flow (UBF).

MATERIALS AND METHODS

In this study, 18 healthy, virgin female Sprague-Dawley rats aged 8-week-old were used. The animals were divided into the sham group (n = 9) and the vaginal distension (VD) group (n = 9). The sham group underwent one catheterization of the vagina without distension and the VD group underwent one VD. Following the VD or sham treatment for one week, LSCI assessment of urethral blood flow was performed during bladder filling and leak point pressure (LPP) process.

RESULTS

During the LPP process, in the VD group, the mean LPP was significantly lower than in the sham group (p < 0.05) and the mean UBF level was also significantly lower than in the sham group (p < 0.05) in the LPP condition. The mean relative change of UBF (Δ Flow) was significantly different between the sham group and VD group. The value was 0.646 ± 0.229 and 0.295 ± 0.19, respectively (p < 0.05). During the bladder filling process, the VD group had a significant lower mean UBF level than the sham group under full bladder conditions (p = 0.008). The mean ΔFlow was also significantly lower than in the sham group. The value was 0.115 ± 0.121 and 0.375 ± 0.127, respectively (p = 0.016).

CONCLUSIONS

The results confirmed that LSCI was able to determine UBF in female rats. The VD group had lower baseline UBF and lower increases in UBF during bladder filling and LPP process compared with the sham group.

Magnetic targeting of super-paramagnetic iron oxide nanoparticle labeled myogenic-induced adipose-derived stem cells in a rat model of stress urinary incontinence

Cell-based injectable therapy utilizing stem cells is a promising approach for the treatment of stress urinary incontinence (SUI). Applying a magnetically controlled cell delivery approach has enormous potential to enhance cell retention capability within the specified site. To assess the therapeutic efficacy of cellular magnetic targeting, we applied an external magnetic force to target an adipose-derived stem cell based therapy in a rat model of SUI. The results revealed that magnetic attraction of transplanted cells under the magnetic field was generated by cell uptake of superparamagnetic iron oxide nanoparticles in vitro. More importantly, magnetic targeting improved the retention rate of transplanted cells and facilitated the restoration of sphincter structure and function in a rat SUI model according to the results of histological examination and urodynamic testing. Therefore, magnetically guided targeting strategy might be a potential therapy method for treatment of SUI.

Color Doppler dynamic tissue perfusion measurement: a novel tool in the assessment of renal parenchymal perfusion in children with vesicoureteral reflux

INTRODUCTION

Vesicoureteral reflux (VUR) occurs in 20-50% of children suffering from recurrent urinary tract infections (UTIs) and is associated with an increased risk of renal scarring and impaired renal function. Early detection of renal perfusion deterioration would allow for the implementation of more aggressive treatment and potentially prevent further damage to the renal parenchyma. The aim of the study was to assess renal parenchymal perfusions in children with recurrent UTIs with and without coexisting VUR, and compare the findings with the results of healthy patients.

MATERIAL AND METHODS

Color Doppler sonographic dynamic renal parenchymal perfusion measurements were performed with PixelFlux (Chameleon-Software, Germany) software in 77 children with recurrent UTIs and coexisting VUR and in 30 children with UTIs without VUR. The findings were compared with the results of 53 healthy children.

RESULTS

Cortical parenchymal perfusion of children suffering from UTIs and VUR was significantly reduced when compared to the control group. Statistically significant differences (p < 0.05) were found in all perfusion parameters (i.e. mean velocity (v mix ), mean perfused area (A mix ), mean perfusion intensity (I mix ), tissue pulsatility index (TPI), and tissue resistance index (TRI)) between the control group and children suffering from UTIs and VUR, particularly VUR grades III and IV. There were no significant differences between the UTI group and the control group. No differences were found between the controls and VUR grade II.

CONCLUSIONS

Renal parenchymal perfusion decreases significantly with higher grades of VUR.

Umbilical vein vasomotion detected in vivo by serial three-dimensional pixelwise spatially angle-corrected volume flow measurements

OBJECTIVE

To explore changes in volume flow in the umbilical vein in healthy second-trimester fetuses.

METHODS

This was a prospective observational pilot study performed at Stavanger University Hospital, Norway, between May and October 2013. Serial three-dimensional ultrasound recordings from the umbilical vein were acquired every 30 s in a 5-min period in 43 fetuses at 17-20 weeks' gestation. The recordings were analyzed with pixelwise spatially angle-corrected volume flow measurements.

RESULTS

We observed variation in the umbilical vein volume flow in all fetuses, ranging from a mean minimum of 1.01 mL/s to a mean maximum of 2.60 mL/s. The minimum of all measurements was 57% compared with the mean value and the maximum was 148% of the mean value. The individual flow volume measurements ranged between 0.11 and 4.14 mL/s (mean, 1.76 mL/s). Within this range, an undulating course of all perfusion parameters was observed, with a full period of 4-5 min duration.

CONCLUSION

Healthy second-trimester fetuses show cyclical variation in blood flow in the umbilical vein. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Assessment of urethral vascularity using 2D colour Doppler high-frequency endovaginal ultrasonography in women treated for symptomatic stress urinary incontinence: 1-year prospective follow-up study

INTRODUCTION

Urethral vascularity is responsible for organ perfusion. It is also believed to contribute to maintaining the normal tension in the urethral mucosa and contributes to approximately one third of urethral closure pressure. We hypothesised that in women undergoing treatment for stress urinary incontinence (SUI), there is no change in blood flow intensity.

METHODS

In this pilot study we recruited women attending the urogynaecology clinics between July and October 2009. Exclusion criteria included symptoms of pelvic organ prolapse or urinary tract infection. Colour Doppler ultrasound was performed at the level of the mid-urethra using a high-frequency (9-12 MHz) endovaginal ultrasonography (EVUS) focusing on the following vascular parameters: flow velocity (V), area of the vessels (A), intensity of perfusion (I), Tissue Pulsatility Index (TPI) and Tissue Resistance Index (TRI). Vascular assessments were repeated at 1 year.

RESULTS

We examined 67 women with symptoms of SUI (17 women had surgery and 50 conservative management, i.e., pelvic floor muscle exercises). The mean (± SD) age in the conservative and surgical groups was 46 (±11) and 40 (±9) years respectively and median (range) parity was 2 (0-8) in both groups. Compared to baseline, no statistically significant differences were observed within each group (p > 0.05) or between the values of vascular parameters (V, A, I, TRI and TPI) at 1 year. There was also no difference in vascular parameters between the two groups.

CONCLUSION

At 12 months there is no change in vascularity parameters in women who opt for conservative or surgical treatment of SUI.

Cell Therapy for Stress Urinary Incontinence

Urinary incontinence (UI) is the involuntary loss of urine and is a common condition in middle-aged and elderly women and men. Stress urinary incontinence (SUI) is caused by leakage of urine when coughing, sneezing, laughing, lifting, and exercise, even standing leads to increased intra-abdominal pressure. Other types of UI also exist such as urge incontinence (also called overactive bladder), which is a strong and unexpected sudden urge to urinate, mixed forms of UI that result in symptoms of both urge and stress incontinence, and functional incontinence caused by reduced mobility, cognitive impairment, or neuromuscular limitations that impair mobility or dexterity. However, for many SUI patients, there is significant loss of urethral sphincter muscle due to degeneration of tissue, the strain and trauma of pregnancy and childbirth, or injury acquired during surgery. Hence, for individuals with SUI, a cell-based therapeutic approach to regenerate the sphincter muscle offers the advantage of treating the cause rather than the symptoms. We discuss current clinically relevant cell therapy approaches for regeneration of the external urethral sphincter (striated muscle), internal urethral sphincter (smooth muscle), the neuromuscular synapse, and blood supply. The use of mesenchymal stromal/stem cells is a major step in the right direction, but they may not be enough for regeneration of all components of the urethral sphincter. Inclusion of other cell types or biomaterials may also be necessary to enhance integration and survival of the transplanted cells.

Vascularity of the urethra in continent women using colour doppler high-frequency endovaginal ultrasonography

Objectives

To assess the urethral vascularity in continent women using colour doppler high frequency endovaginal ultrasonography (EVUS).

Methods

We recruited 61 continent women attending gynaecology clinics between July and October 2009. Exclusion criteria included symptoms of urinary incontinence, voiding dysfunction, pelvic organ prolapse or urinary tract infection. The participants underwent EVUS using high frequency (9-12 MHz) biplane transducer (type 8848 BK Medical), according to a standardised protocol. Colour Doppler US was performed in sagittal plane and in transverse plane at the level of the mid-urethra. Ten seconds video files were recorded and following vascular parameters: flow velocity (V_mix), area of the vessels (A_mix), intensity of vascularity (I_mix), pulsatility index (PI_mix) and resistance index (RI_mix) was evaluated.

Results

There were 30 nulliparous (49.2%) women and 31 multiparous women (50.8%) with a mean (±SD) age of 32 (±4) and 46 (±6) years respectively. Significant impairment of vascularity was observed in multiparous patients as compared to nulliparous and was reflected by increased values of RI_mix (p < 0.001) and PI_mix (p < 0.001), and decreased values of V_mix (p < 0.001), A_mix (p < 0.001), I_mix (p < 0.001) in axial and midsagittal sections of the midurethra. A significant decrease of mean value ± SD of I_mix- from 0.02 ± 0.02 in nulliparous to 0.005 ± 0.01 in multiparous was observed.

Cronbach alpha, used to assess vascular correlations and parity demonstrated a reduction when expressed only for vascular parameters, indicating that number of deliveries is an important factor while assessing urethral vascularity.

Conclusions

Compared to continent nulliparous women, continent multiparous women demonstrated a significant reduction in the vascularity parameters in all measured variables when parity was accounted for.

Advances in knowledge

This study provides the basis for further research in assessing urethral vascularity in women.

Use of contrast-enhanced sonography to investigate intraneural vascularity in a cohort of Macaca fascicularis with suspected median mononeuropathy

OBJECTIVES

The purpose of this study was to provide clinical evidence of the use of contrast-enhanced sonography in detecting and quantifying changes in intraneural vascularity due to median mononeuropathy.

METHODS

Five Macaca fascicularis monkeys were exposed to 20 weeks of repetitive work to increase their risk of developing median mononeuropathy. Contrast-enhanced sonograms were obtained in 30-second increments for 7 minutes while a contrast agent was being delivered. Data were collected immediately at the conclusion of the 20-week work exposure and then again during a recovery phase approximately 3 months after the completion of work. Quantitative analysis and trend graphs were used to analyze median nerve perfusion intensity. This study also compared the use of both manual counting of pixels and semiautomatic measurement using specialized software.

RESULTS

Based on the average data, maximum intensity values were identified as the best indicators of nerve hyperemia. Paired t tests demonstrated significantly higher maximum intensities in the working stage for 4 of the 5 subjects (P < .01).

CONCLUSIONS

This study provides preliminary evidence that (1) in a controlled exposure model, a change in intraneural vascularity of the median nerve between working and recovery can be observed; (2) this vascular change can be measured using an objective technique that quantifies the intensity of vascularity; and (3) contrast-enhanced sonography may improve the ability to reliably capture and measure low-flow microvascularity.