Lukas J. Hefermehl

Tumor-associated macrophages subvert T-cell function and correlate with reduced survival in clear cell renal cell carcinoma

Although malignant cells can be recognized and controlled by the immune system, in patients with clinically apparent cancer immunosurveillance has failed. To better understand local immunoregulatory processes that impact on cancer progression, we correlated intratumoral immunological profiles with the survival of patients affected by primary clear cell renal cell carcinoma (ccRCC). A retrospective analysis of 54 primary ccRCC samples for 31 different immune response-related transcripts, revealed a negative correlation of CD68 (a marker of tumor-associated macrophages, TAMs) and FOXP3 (a marker of regulatory T cells, Tregs) with survival. The subsequent analysis of 12 TAM-related transcripts revealed an association between the genes coding for CD163, interferon regulatory factor 4 (IRF4) and fibronectin 1 (FN1), all of which have been linked to the M2 TAM phenotype, with reduced survival and increased tumor stage, whereas the opposite was the case for the M1-associated gene coding for inducible nitric oxide synthetase (iNOS). The M2 signature of (CD68+) TAMs was found to correlate with CD163 expression, as determined in prospectively collected fresh ccRCC tissue samples. Upon co-culture with autologous tumor cells, CD11b+ cells isolated from paired blood samples expressed CD163 and other M2-associated proteins, suggesting that the malignant cells promote the accumulation of M2 TAMs. Furthermore, the tumor-associated milieu as well as isolated TAMs induced the skewing of autologous, blood-derived CD4+ T cells toward a more immunosuppressive phenotype, as shown by decreased production of effector cytokines, increased production of interleukin-10 (IL-10) and enhanced expression of the co-inhibitory molecules programmed death 1 (PD-1) and T-cell immunoglobulin mucin 3 (TIM-3). Taken together, our data suggest that ccRCC progressively attracts macrophages and induces their skewing into M2 TAMs, in turn subverting tumor-infiltrating T cells such that immunoregulatory functions are increased at the expense of effector functions.

Lateral temperature spread of monopolar, bipolar and ultrasonic instruments for robot-assisted laparoscopic surgery

To assess critical heat spread of cautery instruments used in robot‐assisted laparoscopic (RAL) surgery.

Lithium Triborate Laser Vaporization of the Prostate Using the 120 W, High Performance System Laser: High Performance All the Way?

PURPOSE Technical modifications of the 120 W lithium-triborate laser have been implemented to increase power output, and prevent laser fiber degradation and loss of power output during laser vaporization of the prostate. However, visible alterations at the fiber tip and the subjective impression of decreasing ablative effectiveness during lithium-triborate laser vaporization indicate that delivering constantly high laser power remains a relevant problem. Thus, we evaluated the extent of laser fiber degradation and loss of power output during 120 W lithium-triborate laser vaporization of the prostate. MATERIALS AND METHODS We investigated 46 laser fibers during routine 120 W lithium-triborate laser vaporization in 35 patients with prostatic bladder outflow obstruction. Laser beam power was measured at baseline and after the application of each 25 kJ during laser vaporization. Fiber tips were microscopically examined after the procedure. RESULTS Mild to moderate degradation at the emission window occurred in all fibers, associated with a loss of power output. A steep decrease to a median power output of 57.3% of baseline was detected after applying the first 25 kJ. Median power output at the end of the defined 275 kJ lifespan of the fibers was 48.8%. CONCLUSIONS Despite technical refinements of the 120 W lithium-triborate laser fiber degradation and significantly decreased power output are still detectable during the procedure. Laser fibers are not fully appropriate for the high power delivery of the new system. There is still potential for further improvement in the laser performance.

Electrical microcurrent to prevent conditioning film and bacterial adhesion to urological stents

Long-term catheters remain a significant clinical problem in urology due to the high rate of bacterial colonization, infection, and encrustation. Minutes after insertion of a catheter, depositions of host urinary components onto the catheter surface form a conditioning film actively supporting the bacterial adhesion process. We investigated the possibility of reducing or avoiding the buildup of these naturally forming conditioning films and of preventing bacterial adhesion by applying different current densities to platinum electrodes as a possible catheter coating material. In this model we employed a defined environment using artificial urine and Proteus mirabilis. The film formation and desorption was analyzed by highly mass sensitive quartz crystal microbalance and surface sensitive atomic force microscopy. Further, we performed bacterial staining to assess adherence, growth, and survival on the electrodes with different current densities. By applying alternating microcurrent densities on platinum electrodes, we could produce a self regenerative surface which actively removed the conditioning film and significantly reduced bacterial adherence, growth, and survival. The results of this study could easily be adapted to a catheter design for clinical use.

Prospective evaluation of irrigation fluid absorption during pure transurethral bipolar plasma vaporisation of the prostate using expired‐breath ethanol measurements

To investigate if absorption of irrigation fluid occurs during bipolar plasma vaporisation (BPV) of the prostate. To examine the clinical predictors of increased risk of fluid absorption and to assess if changes in serum electrolytes, venous pH, haemoglobin or haematocrit are able to detect intra‐operative fluid absorption.

Absorption of Irrigation Fluid Occurs Frequently during High Power 532 nm Laser Vaporization of the Prostate

PURPOSE Absorption of irrigation fluid was not detected during GreenLight™ laser vaporization of the prostate using the first generation 80 W laser. However, data are lacking on intraoperative irrigation fluid absorption using the second generation 120 W high power laser. We assessed whether fluid absorption occurs during high power laser vaporization of the prostate. MATERIALS AND METHODS We performed this prospective investigation at a tertiary referral center in patients undergoing 120 W laser vaporization for prostatic bladder outlet obstruction. Normal saline containing 1% ethanol was used for intraoperative irrigation. The expired breath ethanol concentration was measured periodically during the operation using an alcometer. The volume of saline absorption was calculated from these concentrations. Intraoperative changes in hematological and biochemical blood parameters were also recorded. RESULTS Of 50 investigated patients 22 (44%) had a positive breath ethanol test. Median absorption volume in the absorber group was 725 ml (range 138 to 3,452). Ten patients absorbed more than 1,000 ml. Absorbers had a smaller prostate, more capsular perforation, higher bleeding intensity and more laser energy applied during the operation. Three patients (13%) had symptoms potentially related to fluid absorption. Hemoglobin, hematocrit and serum chloride were the only blood parameters that changed significantly in the absorber group. The changes were significantly different than those in nonabsorbers. CONCLUSIONS Fluid absorption occurs frequently during high power laser vaporization of the prostate. This should be considered in patients who present with cardiopulmonary or neurological symptoms during or after the procedure.

Thermal Spread of Vessel-Sealing Devices Evaluated in a Clinically Relevant in vitro Model

Introduction: Bipolar vessel-sealing devices (VSDs) have advantages in urological surgeries (less hemorrhage, shorter operating time). However, these instruments can cause thermal injuries, which can result in neural damage and necrosis. The objectives of this study were to establish a reproducible in vitro model for standardized assessment of electrosurgical devices and to evaluate whether optimized placement of surgical instruments can reduce the thermal spread. Methods: We evaluated thermal spread of two VSDs in vitro using thin bovine muscle strips. Thermal injury was measured using an infrared camera, temperature probes and histology. The recordings were made with the VSD alone and with a rectangular clamp next to the VSD. Results: Both instruments showed a significant temperature spread of 2.5 mm lateral to the VSD. The placement of a metal clamp next to the VSD significantly reduced the temperature spread. Histological examinations were able to underline these findings. Conclusions: In this study we describe a straightforward clinically relevant in vitro model for the evaluation of future electrosurgical instruments. We demonstrated that the thermal spread of VSD could be further reduced by optimized placement of an additional surgical instrument. Our results could help surgeons protect sensitive structures like nerves in the vicinity of the VSD.

Continuous Low-Dose Aspirin Therapy in Robotic-Assisted Laparoscopic Radical Prostatectomy Does Not Increase Risk of Surgical Hemorrhage

BACKGROUND Withdrawal of oral antiplatelet therapy (OAT) is a major risk factor for stent thrombosis, myocardial infarction, and cerebral strokes. In order to minimize the risk for thrombotic complications, since 2007 robotic-assisted laparoscopic radical prostatectomy (RARP) has taken place under continuous OAT with aspirin at our institution. In this retrospective study we analyzed the risk for perioperative bleeding and surgical outcome after RARP with OAT. PATIENTS AND METHODS All patients who underwent RARP with aspirin OAT at our institution since 2007 were included in this analysis. The OAT group was compared with a group that underwent RARP without OAT, which contained twice the number of patients. Matching of the two groups was performed with regard to the tumor stage and whether a lymph node dissection or nerve-sparing was performed. RESULTS Thirty-eight patients were assigned to the OAT group and 76 to the control group. A difference in the decrease of postoperative hemoglobin concentration was not detectable between the two groups (mean drop of 2.9±1.4 g/dL and 2.9±1.1 g/dL, respectively; P=.93). RARP was completed in all OAT patients without conversion to open surgery. Two of the 38 patients (5.3%) in the OAT group and none in the control group required blood transfusions (P=.11). Equivalent rates of positive surgical margins for pT2 tumors were detected (16% OAT versus 14% control group; P=1.0). No adverse cardiovascular events occurred in either group during the hospitalization. CONCLUSIONS Continued perioperative OAT with aspirin in RARP is safe, feasible, and not associated with increased blood loss.

The role of donor age and gender in the success of human muscle precursor cell transplantation

Autologous cell transplantation for the treatment of muscle damage is envisioned to involve the application of muscle precursor cells (MPCs) isolated from adult skeletal muscle. At the onset of trauma, these cells are recruited to proliferate and rebuild injured muscle fibres. However, a variety of donor‐specific cues may directly influence the yield and quality of cells isolated from a muscle biopsy. In this study, we isolated human MPCs and assessed the role of donor gender and age on the ability of these MPCs to form functional bioengineered muscle. We analysed the cell yield, growth and molecular expression in vitro, and the muscle tissue formation and contractility of the bioengineered muscle, from cells isolated from men and women in three different age groups: young (20–39 years), adult (40–59 years) and elderly (60–80 years). Our results suggest that human MPCs can be successfully isolated and grown from patients of all ages and both genders. However, young female donors provide fast‐growing cells in vitro with an optimum contractile output in vivo and are therefore an ideal cell source for muscle reconstruction. Taken together, these findings describe the donor‐related limitations of MPC transplantation and provide insights for a straightforward and unbiased clinical application of these cells for muscle reconstruction. Copyright

Acknowledging unreported problems with active surveillance for prostate cancer: a prospective single-centre observational study

Objective To report outcomes of patients with localised prostate cancer (PCa) managed with active surveillance (AS) in a standard clinical setting. Design Single-centre, prospective, observational study. Setting Non-academic, average-size hospital in Switzerland. Participants Prospective, observational study at a non-academic, average-size hospital in Switzerland. Inclusion and progression criteria meet general recommendations. 157 patients at a median age of 67 (61–70) years were included from December 1999 to March 2012. Follow-up (FU) ended June 2013. Results Median FU was 48 (30–84) months. Overall confirmed reclassification rate was 20% (32/157). 20 men underwent radical prostatectomy with 1 recurrence, 11 had radiation therapy with 2 prostate-specific antigen relapses, and 1 required primary hormone ablation with a fatal outcome. Kaplan-Meier estimates for those remaining in the study showed an overall survival of 92%, cancer-specific survival of 99% and reclassification rate of 41%. Dropout rate was 36% and occurred at a median of 48 (21–81) months after inclusion. 68 (43%) men are still under AS. Conclusions Careful administration of AS can and will yield excellent results in long-term management of PCa, and also helps physicians and patients alike to balance quality of life and mortality. Our data revealed significant dropout from FU. Patient non-compliance can be a relevant problem in AS.