PubMed2002
The authors have prospectively documented that men who undergo orthotopic bladder substitution more frequently experience bacteriuria than do normal men [19] or men with carcinoma of the prostate scheduled to have radical prostatectomy (see Table 1). Because the frequency of bacteriuria in men after prostatectomy was also lower than that after orthotopic bladder substitution (see Table 1), removal of the prostate and any of its presumed antibacterial properties probably does not account for this difference. Furthermore, the authors' data (see Table 5 ) and that of Woodside and associates [23] demonstrate that intestine incorporated into the genitourinary tract generates a local antibody response against urinary bacteria. Although others have suggested that the incorporation of bowel in the urinary tract may be associated with increased bacteriuria, this effect has never been documented prospectively. The mechanism of this increased frequency of bacteriuria is unknown. Because the anatomy of the male secretory genitourinary system may be altered after radical prostatectomy and orthotopic bladder substitution, the authors evaluated local antibody production before and after these operations. More than 20 years ago, Burdon [5] found that the initial portion of the VB1 sample in men had significantly higher levels of IgA compared with the VB2 specimen, whereas the levels of IgG were similar in the two portions. This latter finding was confirmed by Shorliffe and co-workers [22] when they examined prostatic secretion. Other investigators have found high levels of IgA in human prostatic tissue and fluid. [24,25]. On the basis of these findings, it was believed that, in men, the prostate produces most of the urinary IgA, whereas the bladder or upper urinary tracts make most of the urinary IgG. Although the authors' study confirms that most local urinary tract IgG is produced by the bladder or upper urinary tracts, this study documents that the prostate is not the only source of urethral IgA in men. Despite almost complete removal or prostate secretory epithelium by radical prostatectomy, as evidenced by a dramatic fall in postoperative VB1 and VB2 PSA compared with preoperative levels (Table 3). men who had this operation had only slightly decreased IgA levels after the operation (Table 4, Fig I). The source of this IgA must be urethral because the VB1 urinary stream contains more IgA than the VB2 urine even after radical prostatectomy. The authors have not determined whether the urinary IgA concentrations observed after radical prostatectomy are the true baseline values for a man without a prostate, or whether they actually reflect abnormal production of local IgA stimulated by radical prostatectomy. Because post-prostatectomy bacteriuris occurred frequently during urethral catheter drainage, the authors screened for postoperative IgA titers to mix 1 and mix 2 to determine whether specific production of antibody against gram-negative organisms might account for some of the postoperative IgA measured. Postradical prostatectomy mix 1 and mix 2 titers were not elevated, compared with preoperative measurements. Because urethral glandular tissue other than prostatic tissue is present in the male urethra, these glands also might be responsible for significant local antibody production. The high levels of urinary IgA and IgG after cystoprostatectomy with ileal orthotopic bladder substitution document that intestine incorporated into the urinary tract is still capable of producing local antibody. This observation corresponds with the findings of Mansson and associated [26] of elevated IgA and IgG in ileal reservoir urine compared with normal urinary tracts. It has been estimated that 1 m of intestine may secrete up to 780 mg/d of IgA [27], indicating that normal intestine production of antibody alone can account for the high IgA and IgG levels found in the patients who underwent bladder substitution. Interestingly, the ratio of IgA to IgG concentration in smal intestine fluid is 2:129, similar to the ratio of IgA to IgG in bladder substitution urine (2.92.1:52, Table 4). Because mix 1 and mix 2 IgA concentrations were elevated in VB1 and VB2 urine after ileal bladder substitution (see Table 5), some of this antibody was produced by the ileal bladder substitution in response to the inevitable bacteriuria that occurs during the prolonged postoperative catheter drainage. The findings is absent after radical prostatectomy alone. In addition, some of this increased antibody might be a result of the increased bacteriuria noted in the patients who underwent ileal bladder substitution after the initial postoperative period. The significance of the increased bacteriuria and elevated antibody levels after ileal bladder substitution is unclear. Because most of these episodes of bacteriuria were asymptomatic, whether they represent clinical infections that should be treated is not known. Bishop and associates [28] found that the bacterial flora of ileal conduits with asymptomatic bacteriuria had bacterial counts of 1000 or fewer colonies, and they noted that the healthy ileum in situ may contain more than 10,000 organisms per milliliter [29]. Because the normal urinary tract is usually sterile, it is possible that the bacteriuria found by the authors after ileal bladder substitution represents some form of bowel colonization more commonly associated with the bowel rather than clinical urinary tract infection and has limited clinial importance. Trinchieri and associated [30] found that urinary from patients with ileocystoplasty prevented attachment of E. coli to human uroepithelial cells more effectively that urine from patients with recurrent urinary infections. This observation suggests that the relatively large quantities of Iga produced by the ileal bladder substitution may, in fact, prevent clinical infection by preventing tissue invasion by the bacteria. Only long-term follow-up of patients with ileocystoplasty or ileal bladder substitution will determine the clinical significance of the bacteriuria. The authors' study had documented an increased incidence of bacteriuria in men after ileal bladder substitution and no such increase after radical prostatectomy. Analysis of the data shows that male sources other than the prostate--probably urethral glands-- must produce significant quantities of local urinary tract IgA. After ileal bladder substitution, the incorporated ileum may produce volumes of local antibody that may exceed the amounts ordinarily produce by the normal urinary tract. The clinical significance of the increased incidence of bacteriuria and elevated antibody levels in patients after illeal bladder substitution is unclear.