Vasectomy and Vasovasostomy in Rhesus Monkeys: The Effect of Circulating Antisperm Antibodies on Fertility**Publication No. 920 from the Oregon Regional Primate Research Center. Supported by Northwestern University/PARFR Subcontract PARFR-70N under Subcontract AID/csd-3608 and National Institutes of Health Grant R000163

Status of spermatogenesis and sperm parameters in langur monkeys following long-term vas occlusion with styrene maleic anhydride

Vas occlusion by styrene maleic anhydride (SMA), trade name RISUG (one of the promising male contraceptive procedures currently in phase III clinical trials), at 60 mg/vas deferens dissolved in 120 micro L dimethyl sulphoxide (DMSO) at up to a 540-day study period caused severe oligospermia in the first 2 to 3 ejaculations and uniform azoospermia in the subsequent ejaculations without toxicity in langur monkeys. The ejaculated spermatozoa were necroasthenoteratozoospermic, suggesting instant sterility. Routine hematology and clinical chemistry parameters and the serum testosterone and sperm antibody titers remained unchanged from their pretreatment values until 540 days vas occlusion. Histology of testes revealed continued spermatogenesis throughout the study period. The stages of spermatogenesis appeared normal until 300 days of vas occlusion. At 360 days of vas occlusion, germ cells appeared in the lumen. Degeneration of seminiferous epithelium was evident in some of the tubules. Following 420 days of vas occlusion, the central portion of the testis showed regressed seminiferous tubules depicting various shapes and devoid of germ cells, which continued until 540 days of vas occlusion. Ultrastructure of the testes after 540 days of vas occlusion revealed vacuolization in the cytoplasm of Sertoli cells and degenerative features in the membranes of the spermatocytes and spermatids in the affected seminiferous tubules. The sub-cellular features of the normal tubules were similar to those of controls. The results suggest focal degeneration of seminiferous epithelium in the central portion of the testis following long-term vas occlusion with SMA.

Antisperm autoantibody responses to vasectomy and vasovasostomy in Fischer and Lewis rats

Antisperm autoantibodies were studied in Fischer and Lewis strains of rats after either vasectomy, vasectomy followed one month later by vasovasostomy, or sham operations. The time course of antibody response to sperm protein autoantigens was assayed by Western blot analysis of sera obtained at intervals up to 3 months. Rats of both strains responded to immunization with isologous spermatozoa with production of high titer hyperimmune sera. Sera from vasectomized Fischer rats showed antisperm antibodies on Western blots, but bands were stained with less intensity and frequency than for Lewis rats. In both Fischer and Lewis strains, major protein autoantigens were observed at 75-83, 68-71, 63, 57, 51, 41, and 21-23 kDa, lending support to the hypothesis that there is a set of dominant sperm autoantigens recognized by a consensus of postvasectomy rat sera. The lesser response of Fischer rats to vasectomy was not due to absence of dominant postvasectomy sperm autoantigens in Fischer sperm extracts, nor was it attributable to inability of Fischer rats to mount an immune response to these antigens, since immunization with isologous sperm was successful in raising antibodies to the dominant autoantigens. Vasovasostomy did not result in a general decrease in antisperm antibodies, and reactions to some antigens actually increased.

Temporal recognition of sperm autoantigens by IgM and IgG autoantibodies after vasectomy and vasovasostomy

Temporal patterns of IgM and IgG autoantibodies to sperm proteins were studied by western blot analysis at intervals after bilateral vasectomy, vasectomy followed one month later by vasovasostomy, or sham operations. Responses were detected to eight major autoantigens at 21-23, 36, 41, 51, 57, 63, 68-71 and 75-83 kDa, by study of staining patterns of sequential serum samples from individual animals and by analysis of the incidence of reaction to each protein. The four lower molecular weight antigens (21-23, 36, 41 and 51 kDa) provoked mainly IgG responses. The strongly stained set of higher molecular weight antigens (57, 63, 68-71 and 75-83 kDa) tended to show more clearly defined temporal patterns of IgM followed by IgG response, including a high incidence of IgM antibody at the 2-week interval. Three of the larger peptides (57, 63 and 68-71 kDa) appeared highly immunogenic, since some reactions were detected even in sham-operated rats. The classical patterns of IgM and IgG antibody responses to the majority of the dominant sperm autoantigens are in accord with the hypothesis that vasectomy mimics immunization with spermatozoa. The high incidence of IgM antibodies in the earliest sample, taken 2 weeks after vasectomy, suggests that the initial immunizing event takes place within about a week after the operation. Vasovasostomy did not bring about a decrease in antisperm antibodies. Instead, some animals demonstrated an increased reaction to certain antigens after reversal of vasectomy, even though the vasovasostomies were anatomically successful.

Early antibody response following vasectomy is related to fertility after vasovasostomy in glucocorticoid-treated and untreated Lewis rats

The influence of treatment with a glucocorticoid on antisperm antibodies and fertility after vasectomy and vasovasostomy was studied in Lewis rats. Animals received a bilateral vasectomy followed 4 weeks later by bilateral vasovasostomy. Treatment with methylprednisolone for two months beginning at the time of the vasovasostomy resulted in a decrease in antisperm antibodies compared with nontreated vasovasostomized animals, but there was no difference in fertility between treated and nontreated vasovasostomized groups. However, when fertile vasovasostomized animals from treated and nontreated groups were compared with infertile vasovasostomized animals, antisperm antibodies were found to be significantly lower in fertile rats 2, 4 and 8 weeks after vasectomy, while antibodies did not differ between fertile and infertile animals at the end of the study (12 weeks). The observation that differences in antisperm antibodies appeared shortly after vasectomy, preceding either vasovasostomy or treatment, suggests that changes occurring very early after vasectomy have far-reaching effects and are among the factors that influence future fertility after vasovasostomy.

The effects of testicular trauma on fertility in the Lewis rat and comparisons to isoimmunized recipients of syngeneic sperm

Adult male Lewis (LEW) rats were used to investigate the effects of unilateral testicular trauma on fertility. Comparisons were made between normal and experimental rats immunized with syngeneic sperm in Complete Freund's Adjuvant (CFA). Matings within the three groups yielded offspring to all normal males, no offspring to the immunized rats, and 27% (3/11) fertility in the trauma group (p less than 0.001). The contralateral testis demonstrated decreased volumes, various degrees of aspermatogenesis and smaller seminiferous tubular diameters, in both the trauma and immunized groups compared to the controls. Similar histopathologic findings of chronic granulomatous inflammation within contralateral testes in both the trauma and immunized groups suggested a common immune etiology for infertility via possible disruption of the blood-testis barrier.

Clinical characteristics of subfertile men with antisperm antibodies

This study investigated the clinical features which could serve as markers to identify subfertile men with antisperm antibodies including age, duration of infertility, history of abdominal or perineal surgery and previous genital trauma. Of the 162 men studied, 43 had a positive test for antisperm antibodies. A significantly greater number of these patients had a history of genital trauma and appendicectomy. Whereas the aetiological role of genital trauma in spermatozoal autoimmunity is readily explicable, that of appendicectomy is not. It can only be postulated that inflammation of the appendix may sometimes affect the vas deferens or that there is some inadvertent injury to the vas deferens during appendicectomy.

Atherosclerosis of cynomolgus monkeys hyper- and hyporesponsive to dietary cholesterol. Lack of effect of vasectomy

A moderately atherogenic diet was fed to young adult cynomolgus macaque males that were observed to be either hypo- or hyperresponsive to dietary cholesterol and who were randomized into groups to be either vasectomized or sham-vasectomized. The extent of atherosclerosis was found to be considerably greater at all arterial sites studied for the monkeys that were hyperresponsive to dietary cholesterol. The differences in atherosclerosis development among the hyperresponder monkeys occurred primarily in the proximal portions of the coronary arteries, the proximal and distal portions of the common carotid arteries, and only in the most proximal portions of the femoral arteries. There were no significant effects of vasectomy or sham vasectomy on atherosclerosis extent in either the hyper- or the hyporesponding groups, although there was a suggestion of somewhat larger lesions in the left circumflex coronary artery of hyperresponder monkeys that were vasectomized and somewhat smaller atherosclerotic lesions in the left common carotid arteries of vasectomized monkeys. The data presented here do not support our first report of worsened atherosclerosis among cynomolgus monkeys fed diets high in cholesterol. The findings of the current study are consistent with recent epidemiological studies of vasectomized and nonvasectomized human males.

Serum sperm agglutinating antibody formation in vasectomized men treated with dexamethasone

The effect of immunosuppression with dexamethasone on sperm antibody formation following vasectomy in men was determined. Vasectomized men were treated with dexamethasone (4 mg) tablets starting two days prior to vasectomy and each day thereafter for a total of eight days for a total dose of 30 mg. There was no significant difference in serum sperm agglutinating antibody, cholesterol, triglycerides, or lipoproteins between the dexamethasone and placebo groups. The finding that immunosuppression at the time of vasectomy did not inhibit sperm antibody formation in man was surprising because in a similar study with Cynomoglus monkeys treatment at the time of vasectomy with dexamethasone inhibited sperm antibody development. The difference between the two studies may be that in monkeys sperm antigen presentation comes at the time of vasectomy and therefore immunosuppression at this time can prevent an immune response, but in man sperm antigen presentation comes at some later time following vasectomy. This species difference in sperm antigen presentation following vasectomy in man compared to monkeys may affect subsequent atherosclerosis development and explain why no cardiovascular disease is found in man following vasectomy.

Comparison of the short-term effects of vasoligation and open-ended vasectomy on the reproductive tract of the male rat

Comparison was made between the short term effects of vasoligation and open-ended vasectomy in the rat at 2, 4 and 8 weeks after surgery. Epididymal granulomata were observed in 2/5 and 1/5 rats respectively 2 and 4 weeks after vasoligation. No epididymal granulomata were observed following open-ended vasectomy, providing some support for the suggestion that this procedure may be beneficial in reducing early post operative complications in the epididymis. An unexpected observation in the 2 week open-ended vasectomy group was the finding that in 2 of 5 animals the proximal end of the vas had been temporarily obstructed by overgrowth of a fibromuscular cap. Increased distal cauda epididymidis tubule diameter in these animals suggested an increased intratubular pressure. No sustained differences were seen in the incidence of granulomata or in the response of the testis or epididymis to either vasectomy procedure by 8 weeks. The results suggest, because of the high incidence of granulomata formation following vasoligation in the rat, that by 8 weeks after surgery both vasectomy procedures are equally effective in preventing further damage in the epididymis caused by elevated intraluminal pressures.

Diet and vasectomy: effects on atherogenesis in cynomolgus macaques

We report here the effect of a moderately atherogenic diet on the progression of atherosclerosis among cynomolgus macaques that were either vasectomized or sham vasectomized. Both groups were compared to sham vasectomized monkeys fed a control Monkey Chow diet. As expected, slight hyperlipoproteinemia induced by the moderately atherogenic diet increased endothelial cell replication rates and resulted in the development of intimal lesions among sham vasectomized monkeys. Unexpectedly, vasectomy resulted in reduced leukocyte adherence to arterial surfaces, reduced endothelial cell replication rates in response to the moderately atherogenic diet, and at most arterial sites, smaller intimal lesions were produced. These data suggest that with slight hyperlipoproteinemia vasectomy may result in a small protective effect against atherosclerosis, while other studies have shown that marked hyperlipoproteinemia in cynomolgus macaques along with vasectomy results in exacerbation of atherogenesis.

Effect of male antisperm antibodies on sperm fertilizability in vitro

Male partners of 129 infertile couples were evaluated for antisperm factors by using the hamster zona-free ovum (HZFO) test. Sperm-agglutinating activity and antifertilization factors were assessed by adding the male partner's serum to donor sperm in the HZFO-serum antibody (HA) test. When patient's HZFO scores were less than 20% of the hamster ova fertilized, fertilization by patient's serum in the HA test. Of 13 samples that failed to fertilize any of the hamster ova, nine were antibody-negative, of which seven had at least one extremely deficient sperm parameter. Of the four men with positive serum, two had normal and one had abnormal semen (one did not have a complete semen analysis). These data emphasize the need to test male partners for a decline in fertilizing capacity, which is frequently related to the presence of serum antisperm factors. These tests could be used to identify paternal and maternal components (sperm and serum) that may hinder fertilization in fertilization programs.

Prevention of monkey sperm penetration of zona-free hamster ova by sperm antibody obtained from vasectomized cynomolgus monkeys

Incubation of antisperm sera from vasectomized cynomolgus monkeys (Macaca fascicularis) with monkey sperm caused a fourfold reduction of sperm attachment to and penetration of zona-free Golden hamster ova. The attachment of sperm to hamster ova was reduced from 64% to 11%, and the penetration of ova was reduced from 20% to 5%. Sperm antibodies block sperm attachment to the vitelline membrane, thus preventing ovum penetration. This blockage may be one of the reasons for low fertility rates observed following reanastomosis of the vas deferens in those vasectomized males that show high levels of circulating antisperm antibody.

Sperm-agglutinating and -immobilizing antibody formation following vasectomy prevented with dexamethasone in cynomolgus monkeys

Cynomolgus monkeys (Macaca fascicularis) were treated with 1.5 mg/kg dexamethasone (DEX) before (4 to 2 days) and after (0, 2, 4, and 7 days) vasectomy. Of the four monkeys treated with DEX, only one developed sperm antibody as measured by sperm-agglutinating and sperm-immobilizing assays. All six of the vasectomized monkeys not given DEX developed both agglutinating and immobilizing sperm antibodies. In this study, DEX given before and after vasectomy blocked sperm-agglutinating and -immobilizing antibody formation. We conclude that the major antigenic exposure to sperm responsible for sperm-agglutinating and -immobilizing antibody comes at the time of vasectomy.

Prevention of autoimmunization to spermatozoa by passive antibody

The objective of this investigation was to determine if sperm antibody formation after vasectomy in guinea pigs can be inhibited by passive administration of antiserum to spermatozoa. Sperm antibody was obtained by bleeding vasectomized guinea pigs which had sperm-agglutinating antibody titers of 1 : 16 or higher. Gamma globulin was obtained by ammonium sulfate precipitation. Vasectomized guinea pigs were injected with immune gamma globulin and normal gamma globulin for a period of two weeks after vasectomy. In the group receiving normal gamma globulin the serum titer of sperm-agglutinating antibody reached 1 : 32 and remained at that level for duration of the study. In guinea pigs receiving immune gamma globulin detectable serum titers of sperm-agglutinating antibody did not develop. The investigation suggests that sperm antibody formation can be prevented by treating vasectomized animals with passive sperm antibody to spermatozoa.

Microsurgical vasovasostomy: immunologic consequences and subsequent fertility

Fifty-five men have undergone microsurgical vasovasostomy with at least a 1-year follow-up. Serum samples from these men were obtained in the preoperative and postoperative periods, and titers of agglutinating and immobilizing antibodies were measured and evaluated in relationship to subsequent fertility. Of the 35 patients in whom adequate serum and semen samples were obtained over a period of 1 year, 17 men proved their fertility and 18 patients in the allotted time span had not yet fathered any children. No statistically significant difference in the level of antibody titers could be found between the fertile group and the infertile group. Seminal antibody titers were determined in 25 men. Five of these men have thus for impregnated their wives. Only a small number of men were found to have positive titers for agglutinating and/or immobilizing antibodies in their semen. The presence or absence of spermagglutinating and/or sperm-immobilizing antibodies in the sera of men who have undergone vasectomy reversal does not seem to interfere with subsequent fertility.

Use of exteriorized stents in vasovasostomy

Ten patients, three to fifteen years postvasectomy, underwent vasovasostomy. Using 2-0 nylon, stents were brought to the scrotal surface. Vas anastomosis was accomplished with a single transmural layer of 6-0 or 7-0 proline or chromic sutures under loupe magnification. Stents were removed in seven to ten days. After two years, a pregnancy rate of 70% was achieved, comparing favorably with other more difficult operative techniques.

Correlation of sperm granulomas and sperm autoantibodies in inbred rats

The relationship between sperm granulomas and antisperm antibodies is speculative. Some investigators believe that sperm granulomas are the result of humoral sensitization, whereas others doubt that they represent an immunologic phenomenon at all. We performed transabdominal bilateral vasectomies by ligation or transection in Brown Norway, Lewis, Fischer, and Sprague-Dawley rats. These strains are known to differ in incidence of antisperm antibody formation following vasectomy. Serum was obtained monthly for determination of antibodies by indirect immunofluroescence. Animals were killed at 6 months and examined for the presence of antisperm antibodies and sperm granulomas. Both antibodies and granulomas were found in 71% of Brown Norway rats. Granulomas were found in all rats of other strains, whereas the incidence of antibodies ranged from 25% to 50%. Thus a specific immunologic relationship between sperm granulomas and antisperm antibodies has not been confirmed.

Vasectomy: five to ten-year follow-up of 200 cases

Five to ten-year follow-up of 200 vasectomies revealed no significant incidence of illnesses or sexual problems.

Vasovasostomy: evaluation of success

Our review of 2,685 cases of vasovasostomy reported between 1948 and 1977 shows that many different surgical techniques can be successful. However, various reporting practices have made case comparisons difficult. We suggest a standardized method for reporting vasovasostomy results.

Is the low fertility rate after vasovasostomy caused by nerve resection during vasectomy?

Cross-sections of human spermatic cords and vasectomy specimens were prepared and the number and cross-sectional area of nerves were determined. On average, about one-half of all nerves in the near neighborhood of the vas deferens were resected during vasectomy. The total cross-sectional area of the nerves along the vasectomy specimens amounted to about one-half of the total area in the spermatic cord samples. The data support the hypothesis that removing nerves to the vas deferens during vasectomy could result in poor functional results after vasovasostomy, i.e., that powerful contraction of the proximal vas deferens and epididymis could be lacking.

Vasectomy increases the severity of diet-induced atherosclerosis in Macaca fascicularis

Diet-induced atherosclerosis developed more extensively in vasectomized cynomolgus monkeys (Macaca fascicularis) than in sham-vasectomized control monkeys fed the same diet. The effect was most pronounced in the abdominal aortas, carotid arteries, distal segments of the coronary arteries, and intracranial cerebral arteries. Antibodies to sperm developed in all vasectomized monkeys, and complement and immunoglobulins were associated with atherosclerotic plaques in some of the vasectomized animals. The immunological response to sperm antigens that often accompanies vasectomy may exacerbate atherosclerosis.

Cell-mediated immunity in vasectomized rhesus monkeys

Cell-mediated immunity in rhesus monkeys that had been vasectomized for 2, 4, 7, or 11 years was measured by lymphocyte blastogenesis following stimulation with concanavalin A, phytohemagglutinin (PHA), and pokeweed mitogens. Several of the 7- and 11-year vasectomized animals had significantly reduced PHA reactivity when compared with control animals, and the percentage of animals with reduced PHA reactivity increased with time after vasectomy.

Incidence of antisperm antibody levels and granulomas in men

Blood samples were collected from 77 men at the time of vasovasostomy and tested for the presence of antisperm antibodies. More men with granulomas had sperm-immobilizing antibodies than did those without granulomas.