Influence of interstitial fibrosis on spermatogenesis after vasectomy and vasovasostomy

Vasovasostomy: A systematic review and meta-analysis comparing macroscopic, microsurgical, and robot-assisted microsurgical techniques

BACKGROUND AND OBJECTIVES

Vasovasostomy is a cost-effective procedure for the reversal of vasectomy. A water-tight adequately blood-supplied mucosal anastomosis is required for better outcomes. This review aimed to compare the outcome of vasovasostomy performed by three different techniques: macroscopic, pure microsurgical, and robot-assisted microsurgical techniques.

METHODS

Scopus, Web of Science, PubMed, Embase, and Cochrane library databases were searched for relevant studies from January 1901 to June 2023. We conducted our quantitative syntheses using the inverse variance method in OpenMeta software. The study's protocol was registered on PROSPERO.

RESULTS

This review involved 95 studies of different designs, with a total sample size of 48,132. The majority of operations were performed bilaterally, and participants were monitored for up to 10 years. The pooled patency rate was the highest following robot-assisted vasovasostomy (94.4%), followed by pure microsurgical vasovasostomy (87.5%), and macroscopic vasovasostomy (83.7%). The pooled pregnancy rate following purely microsurgical vasovasostomy was higher than that of macroscopic vasovasostomy (47.4 vs. 43.7%). Definitive pregnancy rates in robotic vasovasostomy are yet to be determined.

CONCLUSION

Patency outcomes for vasovasostomy were best with robot-assisted microsurgical technique, followed by pure microsurgical technique, and conventional macroscopic technique. Further investigations of robot-assisted microsurgical vasovasostomy outcomes and randomized control trials are required to support this evidence.

Islet transplantation ameliorates diabetes-induced testicular interstitial fibrosis and is associated with inhibition of TGF-β1/Smad2 pathway in a rat model of type 1 diabetes

Islet transplantation (IT) is considered the most effective endocrine replacement therapy for diabetes mellitus (DM). Studies have demonstrated that IT can repair testicular structural injury caused by inflammatory and oxidative stress in a diabetic rat model. However, highly effective exogenous antioxidant and anti-inflammatory drugs can achieve this effect. Testicular interstitial fibrosis caused by long-term hyperglycemia is however difficult to reverse or recover. Thus far, there are no effective drugs that prevent or relieve testicular interstitial fibrosis. Therefore, it is necessary to explore the potential benefit of IT on testicular interstitial fibrosis induced by DM and its underlying molecular mechanisms. In the present study, Wistar rats were used to establish a DM model by intraperitoneal injection of streptozotocin. The diabetic models then underwent IT or received insulin treatment after 12 weeks. IT was more effective than insulin treatment in ameliorating diabetic-induced testicular interstitial fibrosis, Leydig cells apoptosis, testosterone deficiency and poor sperm motility. IT and insulin treatment both significantly inhibited the upregulation of TGF-β1 and phosphorylated Smad2 in DM, with IT being more effective than insulin. The present study's findings proved that IT effectively protects diabetic-induced testicular interstitial fibrosis probably by inhibiting the TGF-β1/Smad2 signaling pathway, which offers hope in male patients with DM complicating with testicular interstitial fibrosis.

Outcomes of partial intussusception and endo-to-side vasoepididymostomy in men with epididymal obstructive azoospermia

OBJECTIVES

Vasoepididymostomy is an ideal surgical approach for epididymal obstructive azoospermia. The aim of the present study was to compare reproductive outcomes of vasoepididymostomy with several anastomotic techniques, including end-to-side and longitudinal intussusception vasoepididymostomy, and partial intussusception and endo-to-side vasoepididymostomy.

METHODS

A case-control study including 110 infertile men with epididymal obstructive azoospermia with mean age of 35 years was carried out. Univariate and multivariate analyses using clinical factors were carried out to predict patency and non-assisted reproductive technology pregnancy. Johnsen score count and proliferating cell nuclear antigen expression were used as surrogates for spermatogenic function. Operative time, number of 10-0 sutures and late failure rates were also compared.

RESULTS

The overall patency and non-assisted reproductive technology pregnancy rates were 70% and 32%, respectively. Multivariate analyses showed that the presence of motile sperm in the epididymis and a higher spermatogenic function (P < 0.05) were independent predictors for patency, and that a higher spermatogenic function and anastomosis at the caput/corpus (P < 0.001) were predictors for non-assisted reproductive technology pregnancy. The operative time was significantly shorter with partial intussusception and endo-to-side than with the other techniques (P < 0.001), and the number of 10-0 sutures was significantly less with partial intussusception and endo-to-side than with longitudinal intussusception vasoepididymostomy (P < 0.01).

CONCLUSIONS

Partial intussusception and endo-to-side as well as end-to-side and longitudinal intussusception vasoepididymostomy are feasible vasoepididymostomy techniques for epididymal obstruction. Spermatogenic function plays important roles in patency and non-assisted reproductive technology pregnancy after vasoepididymostomy. Depending on the surgeon's expertise, partial intussusception and endo-to-side provides similar functional outcomes to those of more established vasoepididymostomy techniques, such as end-to-side and longitudinal intussusception vasoepididymostomy, and it could therefore be considered an effective technique for seminal reconstruction in patients with epididymal obstructive azoospermia.

Age-related changes in interstitial fibrosis and germ cell degeneration of the canine testis

Fifty-five healthy medium-sized dogs were divided into four groups; young (1-3 years old, n = 14), adult (>3 to 6 years old, n = 12), old (>6 to 9 years old, n = 14) and senile (>9 years old, n = 15). After routine orchiectomy, testes were collected, and the degree of white streak areas on cut surfaces was subjectively assessed. Later, testicular tissue sections were stained with haematoxylin and eosin and Masson's trichrome for evaluation of germ cell degeneration and the proportion of interstitial connective tissue, respectively. Semiquantitative severity scoring of germ cell degeneration and quantitative analysis of spermatogenic cells for spermatic index (SI) and Sertoli cell index (SEI) was performed. The score of white streak on cut surface area of the testes increased with age, being higher (p < 0.05) in senile dogs than other age groups; no difference was found between adult and old dogs. The proportion of testicular interstitial fibrosis was highest (p < 0.05) in senile dogs. Positive correlations between age and white streak area (rho = 0.77, p < 0.01) as well as age and interstitial fibrosis (rho = 0.63, p < 0.01) were observed. The severity of germ cell degeneration gradually increased with age and differed among age groups (p < 0.05). Age positively correlated with atrophy of seminiferous tubules (rho = 0.93, p < 0.01). The SI was lower (p < 0.05) in senile dogs compared to other age groups, and SI was not different among young, adult and old dogs. Conversely, SEI was significantly higher in senile dogs compared to young, adult and old dogs. A negative correlation between age and SI (rho = -0.69) and a positive correlation between age and SEI (rho = 0.68) were significant (p < 0.01). In conclusion, influence of age on testicular interstitial fibrosis and germ cell degeneration/depletion were pronounced in dogs over 9 years old.

Abnormal Accumulation of Collagen Type I Due to the Loss of Discoidin Domain Receptor 2 (Ddr2) Promotes Testicular Interstitial Dysfunction

Background

Loss of functional allele for discoidin domain receptor 2 (Ddr2) results in impaired Leydig cell response to luteinizing hormone (LH), low testosterone production and arrested spermatogenesis in older male Ddr2^slie/slie mice. However, the underlying mechanism responsible for this phenotype remains unknown. Herein, we reported for the first time that the deregulated expression of Ddr2 cognate ligand, namely collagen type I (COL1), may account for the disruption of the testicular steroidogenesis in Ddr2^slie/slie mutant testes.

Methodology/Principal Findings

Expression of Ddr2 increased gradually along postnatal development, whereas COL1 expression became negligible from adulthood onwards. In Ddr2^slie/slie mutant testis, however, in contrast to the undetectable staining of Ddr2, COL1 expression was constantly detected, with the highest values detected during adulthood. In the experimental vasectomy model, Ddr2^slie/slie mutant mice exhibited an early androgen deficiency than wild-type mice, along with the accumulation of fibrotic tissue in the interstitium. Functionally, ablation of endogenous Ddr2 resulted in a significant decrease of testosterone (T) level in TM3 cells in the presence of higher concentration of COL1 treatment. Conversely, overexpression of Ddr2 could help TM3 cells to maintain a normal testicular steroidogenesis even in the presence of high concentration of COL1. Additionally, attenuated expression of Ddr2 correlates to the deregulated level of serum T levels in human pathological testes.

Conclusions

Abnormal accumulation of interstitial COL1 may be responsible for the steroidogenic dysfunction in Ddr2^slie/slie mutant testes.

Long-term effect of vasectomy on spermatogenesis in men: a morphometric study

Spermatogenic damage may occur after vasectomy, and the damage is pressure mediated, occurring when the occluded reproductive tract is unable to accommodate additional sperm produced by the testis. This study aimed to determine the long-term effect of vasectomy on spermatogenesis in humans and clarify how the balance between sperm production in the testis and sperm storage in or removal from the tract might be maintained. During inguinal hernia repair, an open biopsy was performed to obtain testicular tissue blocks from 51 Chinese men (aged ≥50 years), of whom 25 (control group) had not undergone vasectomy and 26 (vasectomized group) had undergone bilateral vasectomy 22-42 years before. Methacrylate resin-embedded testicular sections were made, and morphometric studies were performed using light microscopy. In addition, sizes of the testis and epididymis were estimated with ultrasonography. The testicular tissue blocks obtained from one control and seven vasectomized men consisted almost completely of connective tissue. In the other 43 men, significant differences were not found between the two groups in the testicular or epididymal size, qualitative histology or quantitative parameters including the mean diameter or volume fraction of the seminiferous tubules. In conclusion, sperm production and sperm storage/removal reached a static equilibrium after vasectomy, likely due to spermatogenic degeneration or less sperm production as a result of aging or due to vasectomy-induced testicular (interstitial) fibrosis. Thus, complications that might occur in association with overproduction of sperm and distension of the tract would disappear or be relieved with time.

Advanced characterization of microscopic kidney biopsies utilizing image analysis techniques

Correct annotation and identification of salient regions in Kidney biopsy images can provide an estimation of pathogenesis in obstructive nephropathy. This paper presents a tool for the automatic or manual segmentation of such regions along with methodology for their characterization in terms of the exhibited pathology. The proposed implementation is based on custom code written in Java and the utilization of open source tools (i.e. RapidMiner, ImageJ). The corresponding implementation details along with the initial evaluation of the proposed integrated system are also presented in the paper.

A collaborative biomedical image mining framework: application on the image analysis of microscopic kidney biopsies

The analysis and characterization of biomedical image data is a complex procedure involving several processing phases, like data acquisition, preprocessing, segmentation, feature extraction and classification. The proper combination and parameterization of the utilized methods are heavily relying on the given image data set and experiment type. They may thus necessitate advanced image processing and classification knowledge and skills from the side of the biomedical expert. In this work, an application, exploiting web services and applying ontological modeling, is presented, to enable the intelligent creation of image mining workflows. The described tool can be directly integrated to the RapidMiner, Taverna or similar workflow management platforms. A case study dealing with the creation of a sample workflow for the analysis of kidney biopsy microscopy images is presented to demonstrate the functionality of the proposed framework.

Prooxidant-antioxidant balance and malondialdehyde over time in adult rats after tubal sterilization and vasectomy

OBJECTIVE

Sterilization (tubal sterilization and vasectomy) is a widely applied contraceptive method worldwide. Although most studies have described sterilization as a safe method, there are reports of tubal ligation (TL) and vasectomy complications. The aim of this study was to evaluate the effects of TL and vasectomy on the serum oxidative stress, specifically prooxidant-antioxidant balance (PAB) and malondialdehyde (MDA) levels, over time.

METHODS

Male and female rats were classified into vasectomy, sham-vasectomy, TL, and sham-TL groups, respectively. The PAB and MDA levels were measured on days 15 and 45 and months 3 and 6 after the intervention. For female rats, blood sampling was performed during the diestrous phase and estradiol and progesterone were also measured.

RESULTS

Serum PAB and MDA increased after TL (p<0.05). Vasectomy increased serum MDA remarkably after 45 days, 3 months, and 6 months (p<0.05). After vasectomy, serum PAB also increased although not significantly. Serum estradiol and progesterone decreased remarkably in the TL group compared to the sham group (p<0.05).

CONCLUSION

Bilateral TL and vasectomy both increase the serum oxidative stress; however the imbalance after TL was very noticeable. As for the TL, the reduction of serum estrogen levels can be involved in this imbalance. Complications followed by TL or vasectomy could be due to increased levels of oxidants. Thus, prescribing antioxidants during and or after surgery may be a solution.

Increased sperm DNA fragmentation in patients with vasectomy reversal has no prognostic value for pregnancy rate

PURPOSE

We evaluated sperm DNA fragmentation in patients with vasectomy reversal and its prognostic value to determine spontaneous and assisted reproductive technique pregnancy rates.

MATERIALS AND METHODS

We prospectively assessed DNA fragmentation with the sperm chromatin structure assay in postoperative semen samples of 70 patients with vasectomy reversal. At a median +/- SD followup of 4.3 +/- 0.5 years pregnancy rates were recorded.

RESULTS

DNA fragmentation in patients with vasectomy reversal was significantly increased vs that in proven fertile controls (30.2% +/- 20.1% vs 15.3% +/- 5.4%, p <0.001). Significant negative correlations were found between DNA fragmentation index and total sperm count, progressive motility, total number of progressive sperm, normal morphology and sperm vitality (-0.325 <r <-0.805). The obstructive interval did not correlate with DNA fragmentation. The spontaneous pregnancy rate was 46%. Significantly higher log total progressive sperm motility (p = 0.021) and a trend toward lower female age (p = 0.064) were detected in the spontaneous vs the no pregnancy group. No association was found between DNA fragmentation and the pregnancy rate.

CONCLUSIONS

Increased DNA fragmentation is present in semen samples of men after vasectomy reversal vs fertile controls but DNA fragmentation is not associated with spontaneous or assisted reproductive technique pregnancy rates in these patients.

Effects of hemodialysis on testicular volume and oxidative stress in humans

PURPOSE

Male infertility is a serious problem in patients on hemodialysis. Our understanding is that end stage renal disease or hemodialysis causes poor semen quality but the mechanism leading to impaired spermatogenesis is largely unknown.

MATERIALS AND METHODS

Testicular volume in 120 patients on maintenance hemodialysis was compared with that in age matched healthy controls. Volume was correlated with clinical findings. In 10 testicular biopsy specimens from patients on hemodialysis who visited our infertility clinic Western blotting was performed to examine the generation of 4-HNE modified proteins, which are markers of oxidative stress, and the expression of proliferating cell nuclear antigen. Interstitial fibrosis was determined by Masson's trichrome staining.

RESULTS

Mean bilateral testicular volume in patients on hemodialysis was significantly smaller than that in healthy controls (31.7 vs 36.4 ml, p <0.01) in a hemodialysis duration dependent manner (r = -0.32, p <0.01). The increase in serum ferritin correlated inversely with testicular volume (r = -0.25, p <0.01). The generation of 4-HNE modified proteins was significantly increased 3.1-fold in patients on hemodialysis, following the 60% decreased expression of proliferating cell nuclear antigen. Quantitative analysis of Masson's trichrome staining revealed increased interstitial fibrosis in patients on hemodialysis compared with that in controls (41.5% vs 14.8%, p <0.01). Serum ferritin, proliferating cell nuclear antigen expression and interstitial fibrosis correlated with the generation of 4-HNE modified proteins (p <0.05).

CONCLUSIONS

Testicular volume, which is a parameter of spermatogenesis, is impaired in patients on hemodialysis and oxidative stress is considered to be involved in the process. Serum ferritin is a useful parameter for predicting oxidative stress in the testis.

Clinical, ultrasonographic and pathological features following unilateral vasectomy in rams

The effects of vasectomy on testes and related structures of animal species and men are largely disputable. These possible effects were studied in the ram, an established experimental animal model used to investigate genitalia pathophysiology. In each of five rams, vasectomy in the left spermatic cord was carried out; subsequently, the clinical and ultrasonographic features were monitored up to 12 months post-operatively. The rams were sequentially euthanatized 1, 3, 6, 9 and 12 months post-operatively; gross- and histo-pathological examination of their testes and related structures were carried out. Four of the five rams developed sperm granulomas at the proximal to the testis end of vas deferens or/and at the tail of the epididymis; these were palpable from the first and the third month after vasectomy, respectively. Ultrasonographic findings on the vasectomy side were increased size and echogenicity of the epididymal tail, as well as anechoic areas, representing sperm granulomas, visible in the epididymal tail 1 week after vasectomy and in the proximal to the testis end of vas deferens 4 weeks after vasectomy. Gross pathological findings were limited on the vasectomy side and included adhesions between the parietal and the visceral vaginal tunic, enlarged and firm epididymal tail and presence of sperm granulomas at the epididymal tail or/and at the proximal to the testis end of vas deferens; the granulomas contained creamy material. Histopathological changes were observed mainly in the epididymal tails, consisting of a central mass of spermatozoa, surrounded by a layer of macrophages, surrounded in turn by loose vascular connective tissue rich in lymphocytes and plasma cells. With the exception of signs of mild hypospermatogenesis observed in one ram euthanatized 9 months after surgery, and of a slight increase in seminiferous tubule diameter and in seminiferous epithelium height in the rams euthanatized 6 and 9 months after surgery, which are both findings of no clinical importance, no clinical, ultrasonographic, gross- or other histo-pathological changes were observed in the testicular parenchyma during a 12-month post-operative period. These results demonstrate that vasectomy has little if any detrimental effect on the morphologic characteristics of the spermatogenesis in rams.

Quantitative (stereological) study of the effects of vasectomy on spermatogenesis in rabbits

Using stereological methods, especially the optical disector for unbiased estimation of nuclear number, our recent study demonstrated that long-term (6 or 12 months) vasectomy in the rhesus monkey had no significant effects on spermatogenesis (Peng et al. Reproduction 2002, 124, 847-856). This study aimed to determine the scenario in the rabbit using the same morphometric methodology. Three groups of normal male Japanese white rabbits (aged 4-5 months) were subjected to unilateral vasectomy; 10 days, 6 months and 12 months later both testes and epididymides were removed. Testicular and epididymal methacrylate-embedded sections were obtained for stereology. Vasectomy-induced damage to spermatogenesis was observed, primarily sloughing of spermatogenic cells with a greater reduction in the number of advanced (adluminal) cells. The damage was most severe at 10 days, occurring in all the testes on the vasectomized side and involving sloughing of even type A spermatogonia, the number of which returned to normal at 6 and 12 months. Damage was less severe at 6 and 12 months, being found in half of the testes of the vasectomy side, in which the total numbers of later germ cell types were 24.0-59.1% (spermatocytes) and 0.3-11.6% (spermatids) of control at 6 months, and 20.1-22.1% (spermatocytes) and 0.4-12.0% (spermatids) of control at 12 months. By contrast, Sertoli cell number per testis was unchanged following vasectomy in any group. Epididymis on the vasectomy side, especially at 10 days and 6 months, appeared larger than on the contralateral side, but this difference was not statistically significant, and no sperm granuloma was seen in the epididymis.

Stereological analysis of the human testis after vasectomy indicates impairment of spermatogenic efficiency with increasing obstructive interval

OBJECTIVE

To quantify germ cell loss and the extent of testicular fibrosis in vasectomized patients of varying obstructive intervals.

DESIGN

Retrospective study.

SETTING

Specialized male reproductive surgery and endocrinology service.

PATIENT(S)

Thirty-four vasectomized patients 1-20 years after surgery and 10 normal subjects.

INTERVENTION(S)

Thirty-four testicular biopsies taken at the time of vasectomy reversal (vasovasostomy). Control biopsies taken from 10 normal men at the time of vasectomy.

MAIN OUTCOME MEASURE(S)

Stereological assessment of testicular germ cell populations and testicular fibrosis.

RESULT(S)

Vasectomy caused a significant decrease in germ cells in the later stages of spermatogenesis, with significant reductions in pachytene spermatocytes (by 18%), round spermatids (by 40%), elongating spermatids (by 23%), and elongated spermatids (by 39%). The loss of spermatids showed a significant relationship with obstructive interval. A significant 2.7-fold increase in total (peritubular plus interstitial) fibrosis was observed, which showed a positive relationship with obstructive interval. Decreased germ cell populations and fibrosis did not seem to be related to sperm antibody levels nor to sperm counts obtained up to 2 years after vasovasostomy.

CONCLUSION(S)

Vasal obstruction results in significant reductions in germ cells in the later stages of spermatogenesis and increases in testicular fibrosis, both worsening with an increasing obstructive interval. Testicular damage after vasectomy might impact upon the prospects for reversal.

Angiotensin II Dependent Testicular Fibrosis and Effects on Spermatogenesis After Vasectomy in the Rat

PURPOSE

Vasectomy induces testicular interstitial fibrosis in time dependent fashion and inhibits spermatogenesis. We investigated the contribution of angiotensin II (Ang II) to the development of interstitial fibrosis after vasectomy.

MATERIALS AND METHODS

Bilateral vasectomy was performed in 8-week-old Wistar rats and the testes were harvested 1 to 24 weeks after vasectomy. Interstitial fibrosis was evaluated by Masson's trichrome staining. Western blotting and immunohistochemistry were done to examine the expressions of heat shock protein 47 (HSP47), HNE (4-hydroxy-2,3-nonenal) and transforming growth factor-beta1 (TGF-beta1). The antioxidative agent N-acetylcysteine (NAC), the Ang II type 1 receptor antagonist losartan or the Ang converting enzyme inhibitor enalapril was given orally for 24 weeks to vasectomized rats. Spermatogenesis was evaluated by testicular weight and the percent of haploid cells was analyzed by flow cytometry.

RESULTS

Vasectomy significantly increased interstitial fibrosis (more than 8 weeks) and induced the expression of HSP47, HNE modified protein and TGF-beta1. TGF-beta1 and HSP47 immunoreactivity was localized to Leydig cells and fibroblasts. NAC or losartan but not enalapril inhibited the expression of these molecules induced by vasectomy. Increased interstitial fibrosis and impaired spermatogenesis were partially abrogated by NAC or losartan administration.

CONCLUSIONS

There is Ang II type 1 receptor dependent fibrosis after vasectomy. Oxidative condition is considered to trigger and promote these fibrogenic processes. Ang II contributes to the regulation of intratesticular autocrine or paracrine functions after vasectomy.