Urethral reconstruction with autologous urine-derived stem cells seeded in three-dimensional porous small intestinal submucosa in a rabbit model

BACKGROUND

Urethral reconstruction is one of the great surgical challenges for urologists. A cell-based tissue-engineered urethra may be an alternative for patients who have complicated long strictures and need urethral reconstruction. Here, we demonstrated the feasibility of using autologous urine-derived stem cells (USCs) seeded on small intestinal submucosa (SIS) to repair a urethral defect in a rabbit model.

METHODS

Autologous USCs were obtained and characterized, and their capacity to differentiate into urothelial cells (UCs) and smooth muscle cells (SMCs) was tested. Then, USCs were labeled with PKH67, seeded on SIS, and transplanted to repair a urethral defect. The urethral defect model was surgically established in New Zealand white male rabbits. A ventral urethral gap was created, and the urethral mucosa was completely removed, with a mean rabbit penile urethra length of 2 cm. The urethral mucosal defect was repaired with a SIS scaffold (control group: SIS with no USCs; experimental group: autologous USC-seeded SIS; n = 12 for each group). A series of tests, including a retrograde urethrogram, histological analysis, and immunofluorescence, was undertaken 2, 3, 4, and 12 weeks after the operation to evaluate the effect of the autologous USCs on urethral reconstruction.

RESULTS

Autologous USCs could be easily collected and induced to differentiate into UCs and SMCs. In addition, the urethral caliber, speed of urothelial regeneration, content of smooth muscle, and vessel density were significantly improved in the group with autologous USC-seeded SIS. Moreover, inflammatory cell infiltration and fibrosis were found in the control group with only SIS, but not in the experimental autologous USC-seeded SIS group. Furthermore, immunofluorescence staining demonstrated that the transplanted USCs differentiated into UCs and SMCs in vivo.

CONCLUSIONS

Autologous USCs can be used as an alternative cell source for cell-based tissue engineering for urethral reconstruction.

[Value of prostatic massage for detection of Chlamydia trachomatis in the male urethra]

The aim of this work was to evaluate prostatic massage (PM) as diagnostic method of chronic chlamydial infection (possible etiologic agent of male infertility or chronic prostatitis). 105 men were examined. One urethral swabbing and one urine sampling are done before PM. After PM, prostatic fluid is collected spontaneously and in a minimum volume of urine. Chlamydial isolation samples are treated by 3 methods: culture on HeLa 229 cells, immunoenzymology and direct immunofluorescence. Of 107 samplings, 22 were positive. In 13 patients (14 samplings) the result was positive by PM alone. In those cases, prostatic massage was the only way to establish the Chlamydial infection, when urethral swabbing, usual method, is negative. If confirmed, the interest of prostatic massage rests on detection of unknown genital Chlamydial infection, and this, by a non surgical method.

Chlamydial antigen detection in urine samples by immunofluorescence tests

To investigate the diagnostic value of a direct immunofluorescence test (DIF-test), urethral samples and first catch urine (FCU) from 153 male patients attending an outpatient clinic for sexually transmitted diseases (STD) were studied. Of the male patients, 40 (26.1%) had a positive urethral culture, 39 (25.5%) had a positive urethral DIF-test, and 32 (20.9%) were positive in urine according to the DIF-test. The sensitivity and the specificity of the DIF-test in male urine specimens were 75% and 98.2%, respectively, as compared with the chlamydial culture, and 69.2% and 95.6%, respectively, as compared to the DIF-test of the urethral samples. Out of the positive urethral samples, 31% had less than 5 elementary bodies (EBs) and 41% greater than 10 EBs, detected by the DIF-test. The corresponding data for FCU were 47% and 22%, indicating a smaller number of chlamydiae in urine than in urethral samples. False negative results in the urine DIF-test were mostly observed in males with a low number of EBs in the urethra. The DIF-test was less sensitive for FCU than for urethral specimens. Therefore, urine DIF-tests cannot replace conventional methods for chlamydial diagnosis in symptomatic STD patients, but may be recommended when genital sampling is not possible and may serve as an important approach in the control of genital chlamydial infections.

Evaluation of an enzyme immunoassay (Chlamydiazyme) with confirmatory test for the detection of chlamydial antigen in urine from men

First catch urine specimens from 312 male patients were examined for the presence of chlamydial antigen by an enzyme immunoassay (Chlamydiazyme). Positive results were repeated and confirmed using a blocking assay. In addition, urethral swabs were examined by cell culture for Chlamydia trachomatis. Discrepant results were further analysed by direct immunofluorescence (IF) of the spun urine deposit. Paired specimens were positive from 26 subjects, and negative from 276 subjects. Eight paired specimens were urethral culture positive, and urine EIA negative. Two specimens, urine EIA positive but urethral culture negative, were positive on direct IF. The sensitivity, specificity, predictive value of a positive result, and predictive value of a negative result for urine EIA against cell culture and/or direct IF were 77.8%, 100%, 100% and 97.2% respectively.

Interstitial cystitis and the urethral syndrome: a possible answer

A study was made of 20 patients fulfilling the criteria customarily used for the diagnosis of interstitial cystitis. A possible infective aetiology was sought by culture of bladder tissue, catheter and midstream specimens of urine, and urethral swabs by methods capable of detecting fastidious bacteria as well as aerobic pathogens. All bladder biopsies showed the histological appearances usually associated with interstitial cystitis, and bacteria were isolated from the catheter specimens and/or bladder biopsies of 12 patients. Eight of these isolates were fastidious bacteria, Gardnerella vaginalis (6) and Lactobacillus sp. (2). Fastidious bacteria were isolated from the midstream specimen of urine (MSU) and/or urethral swab of 6 other patients. The correlation of the histological and bacteriological findings supports the hypothesis of an infective aetiology and suggests that the so-called urethral syndrome and interstitial cystitis may be the earlier and later stages of the same disease process. The importance of early diagnosis of infection in these patients is emphasised.

Incidence of struvite urinary calculi in two ancestral lines of beagles

In the last 17 years, 55 of 2,125 (2.6%) purebred beagles maintained in a closed colony had urolithiasis. Males comprised 72.7% of the affected animals. All the uroliths except one set in the kidneys were in the urinary bladder, the urethra, or both. All uroliths were nearly pure magnesium ammonium phosphate hexahydrate. Partially inbred beagles had a 10.7% incidence of urolithiasis, compared to a 2.0% incidence in an outbred line.

Characterization and treatment of water, electrolyte, and acid-base imbalances of induced urethral obstruction in the cat

Urethral obstruction induced in adult male cats caused clinical signs identical with those observed in naturally occurring disease. Central nervous system depression, anorexia, dehydration, vomiting, muscle weakness, and hypothermia occurred. Weight loss (due to water loss and catabolism), metabolic acidosis, mild hyponatremia, hyperkalemia, hypermagnesemia, hypocalcemia, hyperphosphatemia, hyperglycemia, azotemia, and hyperproteinemia were also observed. Serum amylase, alkaline phosphatase, and alanine aminotransferase activities were normal. Ten of 13 cats (group 1), with 72 hours' induced obstruction but not treated with parenteral fluids, died either before the obstruction was relieved or within 8 days afterward. Eight cats (group 2) with induced obstruction for 49 to 98 hours developed severe clinical and biochemical alterations. Treatment with a multiple-electrolyte solution, in addition to relief of urethral obstruction, resulted in favorable clinical and biochemical responses. These cats survived and were clinically healthy at 9 to 10 days after relief of obstruction. It was concluded that use of a multiple-electrolyte solution to correct acidosis, restore circulatory volume, and enhance renal excretion of potassium was effective supportive therapy after urethral obstruction was removed.