Advantages of magnetic resonance imaging (MRI) of the seminal vesicles and intra-abdominal vas deferens in patients with congenital absence of the vas deferens

ECFS standards of care on CFTR-related disorders: Identification and care of the disorders

This is the third paper in the series providing updated information and recommendations for people with cystic fibrosis transmembrane conductance regulator (CFTR)-related disorder (CFTR-RD). This paper covers the individual disorders, including the established conditions - congenital absence of the vas deferens (CAVD), diffuse bronchiectasis and chronic or acute recurrent pancreatitis - and also other conditions which might be considered a CFTR-RD, including allergic bronchopulmonary aspergillosis, chronic rhinosinusitis, primary sclerosing cholangitis and aquagenic wrinkling. The CFTR functional and genetic evidence in support of the condition being a CFTR-RD are discussed and guidance for reaching the diagnosis, including alternative conditions to consider and management recommendations, is provided. Gaps in our knowledge, particularly of the emerging conditions, and future areas of research, including the role of CFTR modulators, are highlighted.

Sonography in male infertility: a useful yet underutilized diagnostic tool

PURPOSE

To assess the utility of comprehensive sonographic examination including scrotal sonography, Testicular Doppler and Transrectal Ultrasound (TRUS) to evaluate the male reproductive system and differentiate between obstructive (OG) and non-obstructive (NOG) causes of azoospermia.

METHODS

30 infertile men with azoospermia and 30 control subjects with normospermia underwent sonographic evaluation. FNAC/biopsy findings were used for assigning a final diagnosis of obstructive or non-obstructive azoospermia. Qualitative and quantitative imaging parameters were retrospectively compared between the groups using Chi-square/Fisher's exact test and unpaired t-test, respectively. P < 0.05 was considered significant.

RESULTS

Ectasia of rete testis/epididymal tubules, altered epididymal echogenicity, dilated terminal vas deferens were significantly more common in OG while inhomogeneous testicular echo-texture and reduced testicular vascularity were more common in NOG (P < 0.05). Testicular volume and epididymal head size were significantly higher in OG than in NOG and controls (18.2 ml/10 mm Vs 8.2 ml/7.2 mm and 13.4 ml/8.8 mm respectively; P < 0.05); while Resistive Index (RI) of intra-testicular vessels was higher in NOG as compared to OG and controls (0.65 vs 0.54 and 0.52 respectively; P < 0.05). On ROC curve analysis, cut-off values of testicular volume (AUC: 0.939; P < 0.001), epididymal head size (AUC: 0.772; P = 0.001) and testicular RI (AUC: 0.761; P = 0.001) to differentiate between the groups were 12.1 ml (sensitivity-94.4%; specificity-83.3%), 9 mm (sensitivity-66.7%; specificity-71%) and 0.62 (sensitivity-62%; specificity-100%) respectively.

CONCLUSION

Comprehensive sonographic evaluation can be used to differentiate obstructive from non-obstructive infertility and should be routinely incorporated in the diagnostic workup of infertile men with azoospermia.

Congenital Bilateral Absence of the Vas Deferens

Congenital bilateral absence of the vas deferens (CBAVD) is clinically characterized by the absence of the bilateral vas deferens; the main clinical manifestation is infertility, accounting for 1–2% of male infertility cases. CBAVD may be accompanied by congenital abnormalities in the urogenital system and cystic fibrosis (CF)-related clinical manifestations. CBAVD can develop as a mild manifestation of CF or can be isolated. The main pathogenic mechanism of CBAVD is gene mutation, and CBAVD and CF have a common genetic mutation background. CFTR mutation is the main pathogenic cause of CBAVD and CF, and ADGRG2 mutation is the second most common cause. Although lack of the vas deferens in CBAVD patients causes infertility due to the inability to release sperm, the testes of CBAVD patients have spermatogenic function. Therefore, CBAVD patients can achieve fertility through sperm retrieval surgery and assisted reproductive technology (ART). However, gene mutations in CBAVD patients can have an impact on the ART outcome, and there is a risk of passing on gene mutations to offspring. For CBAVD patients and their spouses, performing genetic counseling (which currently refers mainly to CFTR mutation screening) helps to reduce the risks of genetic mutations being passed on to offspring and of offspring having CF with concomitant CBAVD.

MRI in the evaluation of the azoospermic male

PURPOSE We aimed to show the usefulness of magnetic resonance imaging (MRI) in the evaluation of infertile men and its ability to distinguish obstructive from nonobstructive azoospermia. METHODS Between April 2015 and February 2018, 45 azoospermic men underwent scrotal MRI. We evaluated the images with an emphasis on signal characteristics of the testis and morphologic changes typical for obstruction. Testicular volume (TV), apparent diffusion coefficient (ADC) value, T1 and T2 signal ratios (testis/muscle) were measured for every testis. On the basis of histologic results, patients were divided into two groups: obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). RESULTS Testes of patients in the OA group had significantly lower ADC values (mean 0.876±101 ×10-3 mm2/s) than in the NOA group (mean, 1.114±147 ×10-3 mm2/s). TV was significantly higher in patients with OA (median, 17.61 mL; range, 11.1-38.4 mL) than in those with NOA (median, 10.5 mL; range, 5.2-22.2 mL). ROC analysis showed that both TV and ADC values were highly predictive for distinguishing between OA and NOA patients, with an area under the ROC curve of 0.82 and 0.92 respectively. A cutoff value of ≥12.4 mL could distinguish obstructive from nonobstructive azoospermia with a sensitivity of 92% and specificity of 63%, whereas for ADC measurements a cutoff value of ≥0.952 ×10-3 mm2/s exhibited a sensitivity of 81% and specificity of 90% There was no statistically significant difference in T1 and T2 signal ratios between both groups. Abnormalities typical for obstruction of the male reproductive tract (e.g., dilatation of ejaculatory ducts, prostatic or seminal vesicle cysts) were found in 78% of patients (14/18) in the obstructive group. CONCLUSION Scrotal MRI is a very effective tool for the evaluation of azoospermic men and may provide important information facilitating interventional treatment of infertility.

Cross-sectional imaging of seminal vesicles and vasa deferentia

A wide spectrum of pathologies, ranging from inconsequential degenerative and senile changes to clinically significant neoplasms, can affect seminal vesicles (SVs). With rapid rise in use of magnetic resonance imaging for evaluation of prostate in recent years an increasing number of cases of incidental SV pathologies are encountered by radiologists. Despite the high contrast resolution and high spatial resolution offered by multiparametric pelvic MRI, accurate diagnosis of SV processes can at times be challenging. In this article, we review the anatomy and embryology of the SVs and vasa deferentia and then explore the spectrum of diseases affecting them.

MRI findings of obstructive azoospermia: lesions in and out of pelvic cavity

Obstructive azoospermia (OA) is caused by excurrent duct obstruction, which can occur anywhere along the course of the male reproductive tract and is classically characterized by normal spermatogenesis. To be familiar with the imaging anatomy of normal and abnormal male genital ducts is essential to the diagnosis of OA. In some circumstances, OA can also be related to some specific syndromes; thus, making an accurate diagnosis may require an integral view of the whole abdomen and pelvis. MR is a great complementary imaging modality either for the detection of obstructive factors, especially for characterization of those indeterminate features on ultrasound, or for the identification of specific syndromes related to OA. In this article, a series of patients with OA caused by different kinds of lesions in and out of the pelvic cavity (abdomen) shown on MR imaging were included, and some cases of specific syndromes related to OA were also reviewed.

SLC9A3 Affects Vas Deferens Development and Associates with Taiwanese Congenital Bilateral Absence of the Vas Deferens

Background

The pathophysiology of Taiwanese congenital bilateral absence of the vas deferens (CBAVD) is different from that in Caucasians. In particular, major cystic fibrosis transmembrane conductance regulator (CFTR) mutations and cystic fibrosis are absent in the former. Instead, deficiency in solute carrier family 9 sodium/hydrogen exchanger isoform 3 (SLC9A3) may play a role by generating obstructive azoospermia and degraded epithelial structure in the reproductive tract.

Objectives

The objective of the study was to test whether SLC9A3 variants cause Taiwanese CBAVD.

Materials and Methods

Six-month-old Slc9a3 ^-/-male mice were used to evaluate the effect of long-term SLC9A3 loss on the reproductive system. A case-control cohort of 29 men with CBAVD and 32 fertile men were genotyped for SLC9A3 variants.

Results

SLC9A3 was expressed and localized in the apical border of the epithelium of human vas deferens and glandular epithelium of the seminal vesicle. SLC9A3 deficiency specifically induces atrophy of vas deferens and unfolding of seminal vesicle mucosa in mice. Loss of SLC9A3 increased the incidence of CBAVD in humans from 3.1% to 37.9% (p < 0.001). Up to 75.9% of CBAVD patients carry at least one variant in either SLC9A3 or CFTR.

Discussion

Our findings build upon previous data associated with CBAVD pathogenesis. Here, we now report for the first time an association between CBAVD and loss of SLC9A3 and propose that specific defects in the reproductive duct due to SLC9A3 variants drive CBAVD development.

Conclusion

The data implicate loss of SLC9A3 as a basis of Taiwanese CBAVD and highlight SLC9A3 function in reproduction.

The role of SLC9A3 in Taiwanese patients with congenital bilateral absence of vas deferens (CBAVD)

Congenital bilateral absence of vas deferens (CBAVD) is a special entity in obstructive azoospermia. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are involved in Taiwanese CBAVD but most heterozygous 5T variant. The solute carrier family 9 isoform 3 (SLC9A3) is the Na+/H+ exchanger, which interacts with CFTR and regulates the Ca2+ homeostasis. Loss of SLC9A3 decreases CFTR protein and causes obstructive azoospermia in mice. It also causes mal-reabsorption by the efferent tubules, which leads to the obstructive phenomenon and eventually results in testicular atrophy. In 6-month old SLC9A3 deficiency mice, the atrophy of their vas deferens and seminal vesicles become more prominent. Decreases of CFTR expression in the reproductive organ in the SLC9A3 deficient (-/-) mice prove the interaction between CFTR and SLC9A3 in the reproductive tract. Most of Taiwanese CBAVD have at least one variant of SLC9A3 deletion and CFTR IVS8-5T, which co-contribute to Taiwanese CBAVD. The report indicates SLC9A3 deficiency can reverse the pathological changes in the gastrointestinal tract of CF mice. Further research can explore the definite mechanism of SLC9A3 and its role interacting with CFTR in different organ systems, which can contribute to novel treatment for the patients with cystic fibrosis and CBAVD.

CFTR variants and renal abnormalities in males with congenital unilateral absence of the vas deferens (CUAVD): a systematic review and meta-analysis of observational studies

PURPOSE

CFTR variant is the main genetic contributor to congenital (unilateral/bilateral) absence of the vas deferens (CAVD/CUAVD/CBAVD). We performed a systematic review to elucidate the genetic link between CFTR variants, CUAVD, and the associated risk of renal abnormality (RA).

METHODS

We searched relevant databases for eligible articles reporting CFTR variants in CUAVD. The frequency of CFTR variants and RA, and the odds ratios (ORs) for common alleles and RA risk, were pooled under random-/fixed-effect models. Subgroup analyses and heterogeneity tests were performed.

RESULTS

Twenty-three studies were included. Among CUAVD patients, 46% had at least one CFTR variant, with 27% having one and 5% having two. The allele frequency in CUAVD was 4% for F508del and 9% for 5T. The summary OR for 5T risk in CUAVD was 5.79 compared with normal controls and 2.82 compared with non-CAVD infertile males. The overall incidence of RA was 22% in CUAVD. The pooled OR for RA risk among CUAVD patients was 4.85 compared with CBAVD patients.

CONCLUSION

CFTR variants are common in CUAVD, and the 5T allele may be associated with increased CUAVD risk. CUAVD patients bear a higher RA risk than CBAVD patients, but this is not associated with CFTR variants.

Comorbidity of the congenital absence of the vas deferens

Congenital absence of the vas deferens (CAVD) is a relatively rare anomaly that may contribute to male infertility. The aim of this study was to evaluate the clinical features of patients with CAVD and to emphasise some pathological conditions that may be detected during the infertility work-up or follow-up of these patients. The charts of 150 males with the diagnosis of CAVD were evaluated retrospectively. The demographic characteristics, reasons for attendance, the way of diagnosis, interventions for infertility before and after attendance, physical examination findings, reproductive hormone levels, semen analysis results, genetical analysis results and resultant live birth events were all included in the study. There were 101 bilateral and 43 unilateral CAVD cases. Thirty-two males (30.2%) had some renal abnormalities. Two cases, one with bilateral and one with unilateral agenesis, died because of colon cancer at a young age. One case with CUAVD had acute lymphoblastic leukaemia. Congenital absence of the vas deferens should not be seen only as a fertility problem because of the many genotypic or phenotypic disorders that may be present with it. These disorders can cause serious general health problems either presently or in future and can also be transmitted to future generations.