En bloc re-resection of high-risk NMIBC after en bloc resection: results of a multicenter observational study.

PURPOSE: To investigate the role of en bloc re-resection (EBRS) in patients who had undergone previous en bloc resection for high-risk non-muscle-invasive bladder cancer (NMIBC). METHODS: An international, multicenter, observational retrospective analysis of prospectively collected data. Patients with a high-risk NMIBC who had previously undergone en bloc resection were scheduled for EBRS of the resected area after 40 days. The primary outcome was the presence of residual tumor or recurrence-free survival. RESULTS: Overall, 78 patients underwent EBRS. Only five (6.41%) residual cancers were found: one patient had a pTa G3 (1.28%) cancer and four (5.13%) had a pTis. The detrusor muscle was preserved in all samples. Only one patient had a positive margin on EBRS. No procedure called for a conversion to traditional re-TURBT. No patient experienced bladder perforation or other intra-operative complications. The recurrence rate at the first follow-up cystoscopy (RRFF-C at 3 months) was 3.85% (three patients). The median follow-up period was 30.8 months (range 6.9-76.0 months). In univariate analysis, the only predictor of recurrence was grade. Overall we observed 11 recurrences. Only one tumor progressed to T2 MIBC. CONCLUSIONS: The low rates of residual tumor, recurrence, and progression seem to raise doubts about the efficacy of EBRS in patients who have previously undergone en bloc resection. EBRS appears to be a feasible and safe procedure with a low rate of complications. However, further data will be needed before EBRS can be used in clinical trials or recommended as a treatment modality.

LithoVue™ for renal stone therapy - a perfect fit for high volume academic centers; a retrospective evaluation of 108 cases.

BACKGROUND: Over the last few years the number of flexible ureterorenoscopies, used for renal stone treatment, has risen steadily. This was associated with an increase in costs for maintenance and repair of the fragile ureterorenoscopes used. To overcome this problem single-use devices have been introduced to the market. The aim of this study was to assess surgical outcome and workability for LithoVue™, a single-use flexible ureterorenoscope. METHODS: We retrospectively analyzed all flexible ureterorenoscopies performed at our department between January and October 2017. We included a total of 108 interventions for renal stone therapy, all performed using the single-use device LithoVue™. We assessed patients' characteristics including stone size, count and location. We evaluated the surgical outcome, analyzing stone-free rates, reintervention rates, complication rates, as well as surgery time. Learning curve for single-use ureterorenoscopes was evaluated by comparing the surgical outcome between residents and consultants. RESULTS: The average time needed per intervention was 52,31 min ± 28,11. In 77 out of 108 (71,30%) patients we were able to remove all stones by a single intervention. In 8 patients (7,41%) intra- or postoperative complications occurred, none of which was graded higher than Clavien-Dindo III B. We did not find any statistical differences comparing the surgical outcome between residents and consultants. No technical difficulties occurred during surgery. CONCLUSION: Single-use flexible ureterorenoscopes provide decent working properties resulting in good surgical outcome. Furthermore, they are proven to be easy to handle even for unexperienced surgeons, making them a feasible choice for high volume academic centers.

Postmicturition Dribble: A Physiological Phenomenon?

BACKGROUND: Postmicturition dribble (PMD) is a common condition in the male population. OBJECTIVES: Despite its common occurrence, there are only a few studies on this topic so far. The aim of this study was to investigate possible physiological aspects of PMD. METHOD: Seventeen men complaining of PMD and 10 healthy subjects were assessed via uroflometry, IPSS questionnaire, IIEF-5 questionnaire, and an adapted visual analogue scale (VAS) for ejaculation force -(0-10) and the amount of bother concerning PMD (0-10) were completed. In addition to that, a retrograde urethrography at 40 and 60 cm water column as pressure unit to measure the width of the bulbar urethra was performed, and the amount of PMD was measured with an adjusted pad test. RESULTS: The PMD group showed a significantly worse IPSS score, a lower Qmax rate in uroflowmetry, a worse IIEF-5 score, and a worse VAS score concerning ejaculation force. In both groups, worse IPSS levels correlated with a low bulbar urethral diameter at 40 and 60 cm water column. -Another correlation was found between a high maximum urine flow rate and a larger bulbar urethral diameter at 40 and 60 cm. Both groups showed urine loss after micturition, with no bother (VAS 0) in the control group, whereas the PMD group showed a VAS of 6. CONCLUSIONS: PMD should be regarded as a physiological occurrence in men rather than a disease by itself. Suffering is only to be expected in combination with other lower urinary tract symptoms.

Non-ischemic laparoscopic partial nephrectomy using 1318-nm diode laser for small exophytic renal tumors.

PURPOSE: Warm ischemia (WI) and bleeding constitute the main challenges for surgeons during laparoscopic partial nephrectomy (LPN). Current literature on the use of lasers for cutting and coagulation remains scarce and with small cohorts. We present the largest case series to date of non-ischemic LPN using a diode laser for small exophytic renal tumors. METHODS: We retrospectively evaluated 29 patients with clinically localized exophytic renal tumors who underwent non-ischemic laser-assisted LPN with a 1318-nm wavelength diode laser. We started applying the laser 5 mm beyond the visible tumor margin, 5 mm away from the tissue in a non-contact fashion for coagulation and in direct contact with the parenchymal tissue for cutting. RESULTS: The renal vessels were not clamped, resulting in a WIT (warm ischaemic time) of 0 min, except for one case that required warm ischemia for 12 min and parenchymal sutures. No transfusion was needed, with a mean Hemoglobin drop of 1,4 mg/dl and no postoperative complications. The eGFR did not significantly change by 6 months. Histologically, the majority of lesions (n = 22/29) were renal-cell carcinoma stage pT1a. The majority of malignant lesions (n = 13/22) had a negative margin. However, margin interpretation was difficult in 9 cases due to charring of the tumor base. A mean follow-up of 1.8 years revealed no tumor recurrence. The mean tumor diameter was 19.4 mm. CONCLUSION: The 1318-nm diode laser has the advantages of excellent cutting and sealing properties when applied to small vessels in the renal parenchyma, reducing the need for parenchymal sutures. However, excessive smoke, charring of the surgical margin, and inability to seal large blood vessels are encountered with this technique.

Current trends in partial adrenalectomy.

PURPOSE OF REVIEW: Total adrenalectomy has been the standard treatment for small adrenal masses for years. In recent times, however, partial adrenalectomy and cortex-preserving strategies are gaining more importance. Therefore, we evaluated indications, techniques and outcome of partial adrenalectomy. RECENT FINDINGS: With more small adrenal masses identified through the widespread use of imaging modalities, partial adrenalectomy and cortical-preserving strategies were applied in various indications and techniques. In all original papers published on this topic during the review period of the last 18 months, minimal invasive approaches were used with satisfying surgical and functional outcomes. SUMMARY: There is a definitive trend towards the use of partial adrenalectomy in the treatment of small adrenal masses. In bilateral disease, steroid replacement can be avoided in most cases, whereas successful normalization of pathological endocrine levels was reported in various indications. Therefore, minimal invasive partial adrenalectomy may become the recommended standard treatment of small benign and hormonal active adrenal tumours.

[An incidental finding of retrocaval extraadrenal pheochromocytoma]. / Das retrocavale extraadrenale Phäochromozytom als Zufallsbefund.

As part of diagnostic work-up of a 71-year-old patient with resistant hypertension, an extraadrenal mass was found. After further imaging and biochemical evaluation an extraadrenal pheochromocytoma was diagnosed and after alpha-receptor blockade was removed via posterior approach laparoscopically in the course. The pheochromocytoma is a rare catecholamine-producing tumor with an incidence of 1-2 per 100 000. In about 1-25 % it is located extraadrenal. Establishing the diagnosis is dependent on the demonstration of significant catecholamine excess. Afterwards imaging with CT or MRI should be performed. After administration of alpha-blockers, the complete surgical resection is the treatment of choice.

First clinical application of image-guided intraoperative electron radiation therapy with real time intraoperative dose calculation in recurrent rectal cancer: technical procedure.

Intraoperative radiation therapy (IORT) is a radiation technique applying a single fraction with a high dose during surgery. We report the first abdomino-pelvic application of an image-guided intraoperative electron radiation therapy with intraoperative real time dose calculation based on the individual intraoperative patient anatomy. A patient suffering from locoregionally recurrent rectal cancer after treatment with neoadjuvant re-chemoradiation was chosen for this approach. After surgical removal of the recurrence, an adequate IORT applicator was placed as usual. A novel mobile imaging device (ImagingRing, MedPhoton) was positioned around the patient covering the region to be treated with the IORT-applicator in place. It allowed the acquisition of three-dimensional intraoperative cone-beam computed tomography images suitable for dose calculation using an automated scaling (heuristic object and head scatter as well as hardening corrections) of Hounsfield units. After image acquisition confirmed the correct applicator position, the images were transferred to our treatment planning system for intraoperative dose calculation. Treatment could be accomplished using the calculated dose distribution. We herein describe the details of the procedure including necessary adjustments in the typically used IORT equipment and work flow. We further discuss the pros and cons of this new approach generally overcoming a decade long limitation of IORT procedures as well as future perspectives regarding IORT treatments.

Anterior urethral reconstruction using the circular fasciocutaneous flap technique: long-term follow-up.

PURPOSE: The circular fasciocutaneous skin flap technique (FCF) yields excellent short-term results for complex anterior urethral reconstruction. We performed an observational retrospective and descriptive study to report our long-term experience. METHODS: A total of 36 adults with anterior urethral strictures (AUS) exceeding 3 cm underwent single-stage urethroplasty using the FCF. Exclusion criteria were: lichen sclerosus, absence of the urethral plate and hypospadias. All had a minimum follow-up of 7 years. Mean age was 49.7 years. Radiological work-up was supplemented by urethral ultrasound showing a mean stricture length of 5.9 cm. A circumferential island of distal penile skin was mobilized on a vascularized pedicle and used for urethral reconstruction. Tube repairs were not included. Outcome was considered a failure when post-operative instrumentation was needed. The Mann-Whitney U test was used for statistical analysis. RESULTS: Mean follow-up was 96.7 months (86-117). All received a ventral onlay repair secondary to stricturotomy. Complication rate was 8.3% (3/36): A flimsy stricture at the proximal anastomotic site occurred in 1 requiring optical urethrotomy. In 2 patients, glans dehiscence was noted. No penile skin necrosis was observed proximal to the flap-harvesting site. We did not observe neurovascular lower extremity complications. Long-term success rates exceeded 90%. CONCLUSIONS: FCF-urethroplasty yields excellent long-term results with no late stricture recurrence. All complications occurred early after surgery underlining the durability of pedicled genital skin flaps. Despite extensive stricture, disease complication rates and morbidity were low. In case of paucity of local skin or lichen scleroses, oral grafts are required for optimal treatment.

Impact of clinical parameters on the diagnostic accuracy of endorectal coil MRI for the detection of prostate cancer.

OBJECTIVES: Endorectal coil MRI (endoMRI) of the prostate is useful to evaluate tumor localization. There is little evidence on patient characteristics affecting its diagnostic performance. We evaluate the influence of clinical and histological parameters on the accuracy of endoMRI. METHODS: Sixty-nine patients with prostate cancer were included. After virtually dividing the prostate into pixels of 1 cm2, results of endoMRI were compared with those from prostatectomy specimens' whole-mount sections. Univariate and multivariate analyses were performed to calculate the impact of clinical and histological parameters on the number of appropriately described pixels. RESULTS: In 9, no tumor could be demonstrated by endoMRI. 48.3% of patients were staged correctly, 23.3% were over- and 28.3% understaged. Mean rates of correctly labeled pixels were 0.44 (± 0.04 SEM) for tumor and 0.90 (± 0.01) for benign segments. In univariate analysis, the rate of correctly labeled tumor segments showed significant positive correlations with Gleason score ≥7 and negative correlations with prostate weight and multifocality. The rate of correctly labeled benign segments showed significant negative correlation with tumor weight. All factors were independent variables in multivariate analysis. CONCLUSIONS: The reliability of endoMRI depends on clinical parameters. Higher Gleason scores, unifocal tumors and smaller prostate volumes ameliorate endoMRI performance.

Objective long-term evaluation after distal hypospadias repair using the meatal mobilization technique.

OBJECTIVE: Meatal mobilization (MEMO) by distal urethral preparation has been demonstrated to be an efficient surgical technique for the correction of distal hypospadias offering excellent short-term success rates. This study objectively evaluates individual patient satisfaction using a validated score in the long term. MATERIAL AND METHODS: A total of 218 patients who underwent hypospadias repair using the MEMO technique was identified. Of these, 104 (mean age at time of surgery 4.9 years, range 2-28 years) had a minimum follow-up of 5 years and were eligible for the study. They were investigated by physical examination and self-assessment. An objective evaluation using the validated Hypospadias Objective Scoring Evaluation (HOSE) was done in all patients. RESULTS: Mean follow-up was 6.3 (range 5-8) years. Ninety-nine patients participated in the investigation, an overall survey response rate of 95.2%. One urethrocutaneous fistula occurred, but no cases of stenosis were noted. One patient developed a mild penile deviation during the postoperative follow-up. Ninety-three out of 99 patients reached the maximum of 16 points (median 15, range 12-16) on the HOSE symptom score. CONCLUSION: The MEMO technique demonstrates a surgical success rate of 97% after 2 years. Even in the long-term follow-up of a mean 6.3 years objective outcome data and individual patient satisfaction were excellent. MEMO is a reliable and versatile method for distal hypospadias repair, as reflected by high patient satisfaction.

Topographical sensitivity and specificity of endorectal coil magnetic resonance imaging for prostate cancer detection.

OBJECTIVES: Endorectal coil magnetic resonance imaging (EC-MRI) is useful to evaluate prostate cancer localization. Herein, we evaluate sensitivity and specificity of EC-MRI in different regions of the prostate by comparing the acquired images to whole-mount sections of the prostate after radical prostatectomy. METHODS: 69 patients with localized prostate cancer were included. After virtually dividing the prostate into 12 sectors, results of EC-MRI were compared to corresponding whole-mount sections by contingency analysis. Sensitivity and specificity were calculated for each of the 12 areas as well as for the dorsal and ventral region. RESULTS: Sensitivity right/left was dorsal apex/mid/base 41/41, 60/67 and 73/79%; ventral 33/52, 43/42 and 47/52%. Specificity right/left was dorsal apex/mid/base 92/89, 82/75 and 88/69%; ventral 100/100, 100/92 and 88/83%. Local sensitivity and specificity regarding dorsal versus ventral was 88/100 and 65/87%. CONCLUSIONS: Local sensitivity decreased from basodorsal to apicoventral direction, whereas local specificity increased in the same direction. Therefore, prostate cancers demonstrated by MRI are more prone to be detected in the basodorsal region, whereas less false-positive results are found in the apicoventral region. These variations in topographical specificity and sensitivity need to be considered before radical prostatectomy or MRI-guided biopsy.

Sporadic renal hemangioblastoma: A case report of a rare benign renal tumor.

In renal tumors, suspicious for renal cell carcinoma, where there is any doubt and discrepancy between morphology and immune profile, we recommend performing further immunohistochemical staining for pan-cytokeratin, S100, NSE, and inhibin-alpha. Thus, follow-up overtreatment can be avoided in cases of benign kidney tumors.

Female sexual dysfunction: a new urogynaecological research field.

OBJECTIVE: To critically review published data on the urogynaecological aspects of female sexual dysfunction (FSD), as FSD is a developing multidisciplinary issue associated with several biological, medical and psychological factors. METHODS: The reported prevalence of FSD is 19-50% and women with lower urinary tract symptoms or urinary incontinence (UI) not only complain of a deteriorating of quality of life but also of sexual life with an incidence as high as 26-47%. Furthermore, urogynaecological surgery represents an important but underestimated cause of FSD. Different databases (Pub Medical, Medline, serial titles, the Cochrane library and the NLM gateway database) were searched for the keywords 'sexuality; sexual function; urinary incontinence; pelvic organ prolapse; questionnaire; symptom severity; epidemiology; quality of life; instruments; sexual health; vagina; vaginal surgery; pelvic surgery'. RESULTS: There is a lack of a standardized instrument for assessing FSD. Recent studies investigate the impact of UI on sexual function, but the pathophysiology has not been elucidated. Vaginal or pelvic surgery does not affect overall sexual satisfaction. CONCLUSIONS: Our investigation highlights the need for studies to assess the anatomical, physiological and sensory mechanisms related to FSD. Specific questionnaire are needed to quantify the problem. In the definition, symptoms assessment and preoperative counselling is important, to make a distinction between overall sexual function and individual parameters, such as psychosocial context. Only in this way, will it be possible to identify new therapeutic targets. A definition of success in urogyneacological terms should include aspects of quality of life and quality of sexual life. Immediate research in this field is needed.

Clinical and pathological features of screen vs non-screen-detected prostate cancers: is there a difference?

OBJECTIVE: To evaluate the clinical and pathological characteristics of screen vs non-screen-detected prostate cancers, to determine if there is a difference in the same prostate-specific antigen (PSA) range. PATIENTS AND METHODS: In all, 997 patients who had had a radical prostatectomy were evaluated; 806 were Tyrolean screening volunteers, and 191 were from outside Tyrol, representing the 'referred prostate cancer' group. PSA level, age, prostate volume and pathological characteristics were assessed, as was the amount of over- and under-diagnosis. RESULTS: There were no statistically significant differences in patient age or PSA levels in the two groups. Even in the same PSA range there were statistically significantly more extraprostatic cancers in the referral group, at 31.7% and 17.4%, respectively. In the referred and screening groups there was over-diagnosis in 7.9% and 16.8%, and under-diagnosis in 40.8% and 27.8%, respectively. CONCLUSION: This study suggests that screening volunteers have a statistically significantly higher rate of organ-confined prostate cancers, and a statistically significantly lower rate of extracapsular extension and positive surgical margins than their counterparts in the referral group even in the same PSA range. As the pathological stage and surgical margin status are significant predictors of recurrence, these findings support the concept of PSA screening.

Real-time virtual ultrasonographic radiofrequency ablation of renal cell carcinoma.

OBJECTIVE: To evaluate the usefulness of real-time virtual ultrasonography (RVS) as a new navigational tool for percutaneous radiofrequency ablation (RFA) of solid renal cell carcinoma (RCC). PATIENTS AND METHODS: Ten patients with 13 RCCs were treated with percutaneous RFA using RVS, which displays ultrasonograms and corresponding multiplanar reconstruction images of computed tomography in parallel. RESULTS: RVS allowed excellent anatomical visualization and precise navigation of RFA for RCC. All patients were treated successfully in one session with percutaneous RVS RFA. There were no significant complications, and none of the patients had a local tumour recurrence during the follow-up. CONCLUSION: RVS for RFA of solid RCC is a new and promising alternative imaging method.

Comparison of the precision of transurethral endoscopic versus ultrasound-guided application of injectables.

OBJECTIVE: To compare the precision of transurethral endoscopic- vs ultrasound (US)-guided injections, as transurethral application of various injectables under endoscopic view are widely used to treat urinary incontinence. MATERIAL AND METHODS: Bovine collagen was injected into the lower urinary tract in 20 dead female pigs. In each pig five depots of collagen were injected and there were five pigs in each group. In group I collagen was injected into the urethral wall under endoscopic control. In group II collagen depots were injected periurethrally under endosocopic guidance. In group III collagen was injected into the urethral wall under US control. In group IV collagen depots were injected periurethrally under US guidance. A transurethral US probe (6 F, 15 MHz) and injection device were used for transurethral US-guided injections. In all pigs the urethra and the periurethral tissue were removed after injection and investigated using anatomical preparations and histological sections. RESULTS: In group I only two collagen depots were actually located in the urethral wall in two pigs (two of 25 depots, 8%). In group II five depots in two pigs were located in the urethral wall (five of 25 depots, 20%). The periurethral collagen depots were found to spread out in the loose connective and fat tissue around the urethra. In group III all US-guided injections of collagen were situated in the urethral wall and in group IV they were all located periurethrally. CONCLUSIONS: The present study shows that endoscopic application of injectables is an inaccurate technique, while US-guided injections are precise. US-guided injection enables excellent control of the therapeutic procedure.

Acute pyelonephritis: comparison of diagnosis with computed tomography and contrast-enhanced ultrasonography.

OBJECTIVE: To assess the value of contrast-enhanced ultrasonography (US) with the contrast pulse-sequence (CPS) technique for detecting renal parenchymal changes in acute pyelonephritis (APN), compared with contrast-enhanced computed tomography (CT) as the reference standard. PATIENTS AND METHODS: We examined 100 patients (82 women, 18 men; mean age 30.2 years, range 18-67); children (those aged <18 years) were excluded from the study. All patients had clinical symptoms suggestive of APN. For the US a Sequoia 512 (Acuson, Mountain View, CA, USA) unit including Cadence CPS technology, with a 6C2 probe, was used. A bolus of a 2.4-mL US contrast agent SonoVue (Bracco, Milan, Italy) was injected. For CT a multislice 16-row unit was used (Sensation 16, Siemens, Erlangen, Germany), at a table speed of 2.5 mm/s and a slice thickness of 3 mm; 100 mL of intravenous iodinated contrast agent (flow 3 mL/s) was injected. RESULTS: On contrast CT, 84 patients (84%) had renal parenchymal changes suggestive of APN; on contrast US, 82 of the 84 (98%) showed renal parenchymal changes, and APN was correctly diagnosed. Seventy-six patients (90%) had unilateral and eight (10%) had bilateral APN, and in two (2%) with APN the diagnosis could not be confirmed by US/CPS (false-negative). No false-positive findings were detected on US/CPS, which had a sensitivity of 98%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 89%. CONCLUSION: CPS/US is accurate for detecting parenchymal changes in APN; it is very sensitive and specific, and allows small renal parenchymal changes to be detected with no radiation exposure.

Pathological features of Gleason score 6 prostate cancers in the low and intermediate range of prostate-specific antigen level: is there a difference?

OBJECTIVE: To assess the pathological features of Gleason score 6 prostate cancers after radical prostatectomy in the low (<4 ng/mL) and intermediate range of prostate-specific antigen level (4-10 ng/mL), as such prostate cancers are considered to be well differentiated tumours with a low risk for recurrence after therapy. PATIENTS AND METHODS: In all, 1354 patients with T1c prostate cancer and PSA levels of <10.0 ng/mL had a radical retropubic prostatectomy. Patients with Gleason score 6 tumours were divided into two groups, those with PSA levels of <4 and 4.0-10.0 ng/mL. Extracapsular extension, positive surgical margins, biochemical recurrence (BCR) and mean time to BCR were evaluated. RESULTS: Of the 1354 patients, there were 437 (32.3%) with Gleason score 6 prostate cancers. Patients in the low PSA group had less extraprostatic disease than those with a higher level (5.9% vs 14.5%) and both groups had an almost equal proportion of positive surgical margins (9.4% vs 11.0%). In the low PSA group there was statistically significantly shorter BCR than in the high PSA group, with a mean time to BCR of 1.7 vs 3.1 years. CONCLUSIONS: These results show a statistically significantly higher rate of extraprostatic disease and earlier BCR in men with a high than a low PSA level even in Gleason score 6 prostate cancer. As the rate of BCR and extracapsular extension are significantly related to prostate cancer mortality, these findings further support the concept of screening using low PSA levels.

Over-diagnosis and under-diagnosis of screen- vs non-screen-detected prostate cancers with in men with prostate-specific antigen levels of 2.0-10.0 ng/mL.

OBJECTIVES: To evaluate possible over- and under-diagnosis of prostate cancer in a screened vs a referral population in the same range of prostate-specific antigen (PSA). PATIENTS AND METHODS: In all, 1445 patients undergoing radical prostatectomy and with a PSA level of <10 ng/mL were evaluated; 237 were from outside Tyrol (Austria) and represented the unscreened group, and 1208 were Tyrolean screening volunteers. Over-diagnosis was defined as a pathological stage of pT2a and a Gleason score of <7 with no positive surgical margins. Under-diagnosis was defined as a pathological stage of >or=pT3a or positive surgical margins. The chi-square test was used to assess the differences, with P < 0.05 considered to indicate statistical significance. RESULTS: There were no significant differences in patient age or PSA levels between the study groups. There was over-diagnosis in the screening and referral groups in 17.4% and 8.9%, respectively, and under-diagnosis in 18.6% and 42.2%, respectively. CONCLUSION: This study suggests that patients with prostate cancer participating in a screening programme are less likely to be under-diagnosed or have extracapsular disease than their counterparts in a referral population, even in the same PSA range, after radical prostatectomy. Furthermore, there was more under-diagnosis in the referral group than over-diagnosis in the screened group.

Peripheral infusion of rat bone marrow derived endothelial progenitor cells leads to homing in acute lung injury.

BACKGROUND: Bone marrow-derived progenitors for both epithelial and endothelial cells have been observed in the lung. Besides mature endothelial cells (EC) that compose the adult vasculature, endothelial progenitor cells (EPC) are supposed to be released from the bone marrow into the peripheral blood after stimulation by distinct inflammatory injuries. Homing of ex vivo generated bone marrow-derived EPC into the injured lung has not been investigated so far. We therefore tested the hypothesis whether homing of EPC in damaged lung tissue occurs after intravenous administration. METHODS: Ex vivo generated, characterized and cultivated rat bone marrow-derived EPC were investigated for proliferation and vasculogenic properties in vitro. EPC were tested for their homing in a left-sided rat lung transplant model mimicking a severe acute lung injury. EPC were transplanted into the host animal by peripheral administration into the femoral vein (10(6) cells). Rats were sacrificed 1, 4 or 9 days after lung transplantation and homing of EPC was evaluated by fluorescence microscopy. EPC were tested further for their involvement in vasculogenesis processes occurring in subcutaneously applied Matrigel in transplanted animals. RESULTS: We demonstrate the integration of intravenously injected EPC into the tissue of the transplanted left lung suffering from acute lung injury. EPC were localized in vessel walls as well as in destructed lung tissue. Virtually no cells were found in the right lung or in other organs. However, few EPC were found in subcutaneous Matrigel in transplanted rats. CONCLUSION: Transplanted EPC may play an important role in reestablishing the endothelial integrity in vessels after severe injury or at inflammatory sites and might further contribute to vascular repair or wound healing processes in severely damaged tissue. Therapeutic applications of EPC transplantation may ensue.