A transcriptional cross species map of pancreatic islet cells

OBJECTIVE

Pancreatic islets of Langerhans secrete hormones to regulate systemic glucose levels. Emerging evidence suggests that islet cells are functionally heterogeneous to allow a fine-tuned and efficient endocrine response to physiological changes. A precise description of the molecular basis of this heterogeneity, in particular linking animal models to human islets, is an important step towards identifying the factors critical for endocrine cell function in physiological and pathophysiological conditions.

METHODS

In this study, we used single-cell RNA sequencing to profile more than 50'000 endocrine cells isolated from healthy human, pig and mouse pancreatic islets and characterize transcriptional heterogeneity and evolutionary conservation of those cells across the three species. We systematically delineated endocrine cell types and α- and β-cell heterogeneity through prior knowledge- and data-driven gene sets shared across species, which altogether capture common and differential cellular properties, transcriptional dynamics and putative driving factors of state transitions.

RESULTS

We showed that global endocrine expression profiles correlate, and that critical identity and functional markers are shared between species, while only approximately 20% of cell type enriched expression is conserved. We resolved distinct human α- and β-cell states that form continuous transcriptional landscapes. These states differentially activate maturation and hormone secretion programs, which are related to regulatory hormone receptor expression, signaling pathways and different types of cellular stress responses. Finally, we mapped mouse and pig cells to the human reference and observed that the spectrum of human α- and β-cell heterogeneity and aspects of such functional gene expression are better recapitulated in the pig than mouse data.

CONCLUSIONS

Here, we provide a high-resolution transcriptional map of healthy human islet cells and their murine and porcine counterparts, which is easily queryable via an online interface. This comprehensive resource informs future efforts that focus on pancreatic endocrine function, failure and regeneration, and enables to assess molecular conservation in islet biology across species for translational purposes.

Synaptotagmin-13 orchestrates pancreatic endocrine cell egression and islet morphogenesis

During pancreas development endocrine cells leave the ductal epithelium to form the islets of Langerhans, but the morphogenetic mechanisms are incompletely understood. Here, we identify the Ca²⁺-independent atypical Synaptotagmin-13 (Syt13) as a key regulator of endocrine cell egression and islet formation. We detect specific upregulation of the Syt13 gene and encoded protein in endocrine precursors and the respective lineage during islet formation. The Syt13 protein is localized to the apical membrane of endocrine precursors and to the front domain of egressing endocrine cells, marking a previously unidentified apical-basal to front-rear repolarization during endocrine precursor cell egression. Knockout of Syt13 impairs endocrine cell egression and skews the α-to-β-cell ratio. Mechanistically, Syt13 is a vesicle trafficking protein, transported via the microtubule cytoskeleton, and interacts with phosphatidylinositol phospholipids for polarized localization. By internalizing a subset of plasma membrane proteins at the front domain, including α6β4 integrins, Syt13 modulates cell-matrix adhesion and allows efficient endocrine cell egression. Altogether, these findings uncover an unexpected role for Syt13 as a morphogenetic driver of endocrinogenesis and islet formation.

T cells modulate the microglial response to brain ischemia

Neuroinflammation after stroke is characterized by the activation of resident microglia and the invasion of circulating leukocytes into the brain. Although lymphocytes infiltrate the brain in small number, they have been consistently demonstrated to be the most potent leukocyte subpopulation contributing to secondary inflammatory brain injury. However, the exact mechanism of how this minimal number of lymphocytes can profoundly affect stroke outcome is still largely elusive. Here, using a mouse model for ischemic stroke, we demonstrated that early activation of microglia in response to stroke is differentially regulated by distinct T cell subpopulations - with T_H1 cells inducing a type I INF signaling in microglia and regulatory T cells (T_REG) cells promoting microglial genes associated with chemotaxis. Acute treatment with engineered T cells overexpressing IL-10 administered into the cisterna magna after stroke induces a switch of microglial gene expression to a profile associated with pro-regenerative functions. Whereas microglia polarization by T cell subsets did not affect the acute development of the infarct volume, these findings substantiate the role of T cells in stroke by polarizing the microglial phenotype. Targeting T cell-microglia interactions can have direct translational relevance for further development of immune-targeted therapies for stroke and other neuroinflammatory conditions.

Diet-induced alteration of intestinal stem cell function underlies obesity and prediabetes in mice

Excess nutrient uptake and altered hormone secretion in the gut contribute to a systemic energy imbalance, which causes obesity and an increased risk of type 2 diabetes and colorectal cancer. This functional maladaptation is thought to emerge at the level of the intestinal stem cells (ISCs). However, it is not clear how an obesogenic diet affects ISC identity and fate. Here we show that an obesogenic diet induces ISC and progenitor hyperproliferation, enhances ISC differentiation and cell turnover and changes the regional identities of ISCs and enterocytes in mice. Single-cell resolution of the enteroendocrine lineage reveals an increase in progenitors and peptidergic enteroendocrine cell types and a decrease in serotonergic enteroendocrine cell types. Mechanistically, we link increased fatty acid synthesis, Ppar signaling and the Insr-Igf1r-Akt pathway to mucosal changes. This study describes molecular mechanisms of diet-induced intestinal maladaptation that promote obesity and therefore underlie the pathogenesis of the metabolic syndrome and associated complications.

Sfaira accelerates data and model reuse in single cell genomics

Single-cell RNA-seq datasets are often first analyzed independently without harnessing model fits from previous studies, and are then contextualized with public data sets, requiring time-consuming data wrangling. We address these issues with sfaira, a single-cell data zoo for public data sets paired with a model zoo for executable pre-trained models. The data zoo is designed to facilitate contribution of data sets using ontologies for metadata. We propose an adaption of cross-entropy loss for cell type classification tailored to datasets annotated at different levels of coarseness. We demonstrate the utility of sfaira by training models across anatomic data partitions on 8 million cells.

CD81 marks immature and dedifferentiated pancreatic β-cells

OBJECTIVE

Islets of Langerhans contain heterogeneous populations of insulin-producing β-cells. Surface markers and respective antibodies for isolation, tracking, and analysis are urgently needed to study β-cell heterogeneity and explore the mechanisms to harness the regenerative potential of immature β-cells.

METHODS

We performed single-cell mRNA profiling of early postnatal mouse islets and re-analyzed several single-cell mRNA sequencing datasets from mouse and human pancreas and islets. We used mouse primary islets, iPSC-derived endocrine cells, Min6 insulinoma, and human EndoC-βH1 β-cell lines and performed FAC sorting, Western blotting, and imaging to support and complement the findings from the data analyses.

RESULTS

We found that all endocrine cell types expressed the cluster of differentiation 81 (CD81) during pancreas development, but the expression levels of this protein were gradually reduced in β-cells during postnatal maturation. Single-cell gene expression profiling and high-resolution imaging revealed an immature signature of β-cells expressing high levels of CD81 (CD81high) compared to a more mature population expressing no or low levels of this protein (CD81low/-). Analysis of β-cells from different diabetic mouse models and in vitro β-cell stress assays indicated an upregulation of CD81 expression levels in stressed and dedifferentiated β-cells. Similarly, CD81 was upregulated and marked stressed human β-cells in vitro.

CONCLUSIONS

We identified CD81 as a novel surface marker that labels immature, stressed, and dedifferentiated β-cells in the adult mouse and human islets. This novel surface marker will allow us to better study β-cell heterogeneity in healthy subjects and diabetes progression.

Postoperative change in Gleason score of prostate cancer in fusion targeted biopsy: a matched pair analysis

OBJECTIVE

To evaluate if MRI/ultrasound fusion based targeted biopsy (FBx) leads to a reduced rate of change in Gleason score (GS) compared to prostatectomy specimen.

METHODS

The histopathological findings of the biopsy of the prostate and the radical prostatectomy (RP) specimen of 210 patients who were referred to our hospital between 2012 and 2017 were compared retrospectively in this study. One hundred and five patients who underwent FBx combined with ultrasound-guided 12-core biopsy of the prostate (SBx) were matched with 105 patients who underwent SBx only. This study evaluated the rate of up- or downgrading in the RP specimen in both groups and compared the results via matched pair analysis.

RESULTS

Concordance in Gleason grade group (GGG) was found in 52/105 patients (49.5%) in SBx and in 49/105 patients (46.7%) with FBx (p = 0.679). The rate of downgrading was statistically significant (p = 0.014) and was higher in the FBx group (14/105 patients, 13.3%) than in the SBx group (4/105 patients, 3.8%). A higher rate of upgrading was seen in SBx (49/105 patients; 46.7%) compared to FBx (42/105 patients; 40%), with no statistical significance (p = 0.331). The change in GGG from biopsy to final pathology in patients with GGG 1 and 2 at biopsy level was not statistically significant (p = 0.168).

CONCLUSION

FBx does not decrease the rate of upgrading between biopsy and final pathology in RP specimens. Our results indicate that FBx tends to overestimate the final GGG compared to SBx.

Targeted pharmacological therapy restores β-cell function for diabetes remission

Dedifferentiation of insulin-secreting β cells in the islets of Langerhans has been proposed to be a major mechanism of β-cell dysfunction. Whether dedifferentiated β cells can be targeted by pharmacological intervention for diabetes remission, and ways in which this could be accomplished, are unknown as yet. Here we report the use of streptozotocin-induced diabetes to study β-cell dedifferentiation in mice. Single-cell RNA sequencing (scRNA-seq) of islets identified markers and pathways associated with β-cell dedifferentiation and dysfunction. Single and combinatorial pharmacology further show that insulin treatment triggers insulin receptor pathway activation in β cells and restores maturation and function for diabetes remission. Additional β-cell selective delivery of oestrogen by Glucagon-like peptide-1 (GLP-1-oestrogen conjugate) decreases daily insulin requirements by 60%, triggers oestrogen-specific activation of the endoplasmic-reticulum-associated protein degradation system, and further increases β-cell survival and regeneration. GLP-1-oestrogen also protects human β cells against cytokine-induced dysfunction. This study not only describes mechanisms of β-cell dedifferentiation and regeneration, but also reveals pharmacological entry points to target dedifferentiated β cells for diabetes remission.

Establishment of a high-resolution 3D modeling system for studying pancreatic epithelial cell biology in vitro

OBJECTIVE

Translation of basic research from bench-to-bedside relies on a better understanding of similarities and differences between mouse and human cell biology, tissue formation, and organogenesis. Thus, establishing ex vivo modeling systems of mouse and human pancreas development will help not only to understand evolutionary conserved mechanisms of differentiation and morphogenesis but also to understand pathomechanisms of disease and design strategies for tissue engineering.

METHODS

Here, we established a simple and reproducible Matrigel-based three-dimensional (3D) cyst culture model system of mouse and human pancreatic progenitors (PPs) to study pancreatic epithelialization and endocrinogenesis ex vivo. In addition, we reanalyzed previously reported single-cell RNA sequencing (scRNA-seq) of mouse and human pancreatic lineages to obtain a comprehensive picture of differential expression of key transcription factors (TFs), cell-cell adhesion molecules and cell polarity components in PPs during endocrinogenesis.

RESULTS

We generated mouse and human polarized pancreatic epithelial cysts derived from PPs. This system allowed to monitor establishment of pancreatic epithelial polarity and lumen formation in cellular and sub-cellular resolution in a dynamic time-resolved fashion. Furthermore, both mouse and human pancreatic cysts were able to differentiate towards the endocrine fate. This differentiation system together with scRNA-seq analysis revealed how apical-basal polarity and tight and adherens junctions change during endocrine differentiation.

CONCLUSIONS

We have established a simple 3D pancreatic cyst culture system that allows to tempo-spatial resolve cellular and subcellular processes on the mechanistical level, which is otherwise not possible in vivo.

[Bulbar urethral strictures : A trivial urological disease or a surgical challenge?]

Urethral strictures are often located in the bulbar urethra, and bulbar strictures are commonly due to urethral trauma. Diagnosis is confirmed by radiographic imaging of the urethra. In cases of short primary bulbar strictures, a simple internal urethrotomy may be curative. In contrast, open surgery should be performed in long segment or recurrent strictures because recurrence rates are near 100% in these cases. Depending of the actual findings and comorbidities, end-to-end anastomosis, graft urethroplasty, flap urethroplasty, or perineal urethrostomy may be used. If definitive treatment using open surgery is delayed and multiple endoscopic treatments are tried, urethroplasty becomes more complex and success rates of definitive treatment decline.

Concepts and limitations for learning developmental trajectories from single cell genomics

Single cell genomics has become a popular approach to uncover the cellular heterogeneity of progenitor and terminally differentiated cell types with great precision. This approach can also delineate lineage hierarchies and identify molecular programmes of cell-fate acquisition and segregation. Nowadays, tens of thousands of cells are routinely sequenced in single cell-based methods and even more are expected to be analysed in the future. However, interpretation of the resulting data is challenging and requires computational models at multiple levels of abstraction. In contrast to other applications of single cell sequencing, where clustering approaches dominate, developmental systems are generally modelled using continuous structures, trajectories and trees. These trajectory models carry the promise of elucidating mechanisms of development, disease and stimulation response at very high molecular resolution. However, their reliable analysis and biological interpretation requires an understanding of their underlying assumptions and limitations. Here, we review the basic concepts of such computational approaches and discuss the characteristics of developmental processes that can be learnt from trajectory models.

[Value of imaging in upper urinary tract tumors]

BACKGROUND

Staging of bladder cancer, hematuria as well as the evaluation of unclear findings of the kidneys and ureters are the most frequent indications for imaging of the upper urinary tract (UUT). Endourological assessment of the UUT is much more invasive compared to imaging of the bladder, raising the question of the optimal imaging technique. Several technical improvements regarding computed tomography (CT) as well as magnetic resonance imaging (MRI) were implemented in recent years.

OBJECTIVES

To compare the efficacy and limitations of the most important imaging techniques regarding the UUT.

MATERIALS AND METHODS

Systematic review of the literature and current German, European, and American guidelines regarding bladder cancer, urothelial carcinoma of the UUT and hematuria.

RESULTS

The CT-based urography has superseded excretory urography and is the first choice for imaging of the UUT. In case of contraindications, MRI is a feasible alternative. In all cases, a urography phase is indispensable.

CONCLUSIONS

Imaging of the UUT has to be used in a reasonable combination together with endourological methods and cytology. Optical coherence tomography, confocal laser endomicroscopy and scientific innovations such as radiomics might improve UUT imaging and differential diagnosis of UUT lesions in the future.

Massive single-cell mRNA profiling reveals a detailed roadmap for pancreatic endocrinogenesis

Deciphering mechanisms of endocrine cell induction, specification and lineage allocation in vivo will provide valuable insights into how the islets of Langerhans are generated. Currently, it is ill defined how endocrine progenitors segregate into different endocrine subtypes during development. Here, we generated a novel Neurogenin3 (Ngn3)-Venus fusion (NVF) reporter mouse line, that closely mirrors the transient endogenous Ngn3 protein expression. To define an in vivo roadmap of endocrinogenesis, we performed single-cell RNA-sequencing of 36,351 pancreatic epithelial and NVF+ cells during secondary transition. This allowed to time-resolve and distinguish Ngn3low endocrine progenitors, Ngn3high endocrine precursors, Fev+ endocrine lineage and hormone+ endocrine subtypes and delineate molecular programs during the stepwise lineage restriction steps. Strikingly, we identified 58 novel signature genes that show the same transient expression dynamics as Ngn3 in the 7,260 profiled Ngn3-expressing cells. The differential expression of these genes in endocrine precursors associated with their cell-fate allocation towards distinct endocrine cell types. Thus, the generation of an accurately regulated NVF reporter allowed us to temporally resolve endocrine lineage development to provide a fine-grained single-cell molecular profile of endocrinogenesis in vivo.

[Neuroendocrine prostate cancer]

Neuroendocrine prostate cancer (NEPC) mostly occurs as a treatment-emergent adaptive response under the pressure of intensive androgen deprivation treatment (t-NEPC). Approximately 30-40% of patients with metastatic castration-resistant prostate cancer (mCRPC) also have neuroendocrine involvement. In contrast primary small cell prostate cancer is very rare (<1%). A t‑NEPC should be clinically suspected in patients who have particularly aggressive mCRPC but a disproportionately low prostate-specific antigen (PSA) level and elevated neuroendocrine tumor markers, such as chromogranin A and neuron-specific enolase. The initial Gleason score was shown to be an independent factor correlated to the risk of development of t‑NEPC. Treatment is oriented to that of small cell lung cancer. In patients with negative PSA levels, chemotherapy with cisplatin and etoposide is the first line treatment, for which response rates in the range of 30-60% with a median survival time of usually less than 1 year can be achieved. In patients with much higher serum PSA levels, chemotherapy with carboplatin plus docetaxel should be considered.

[Stricture of the vesicourethral anastomosis after radical prostatectomy]

BACKGROUND

The development of a stricture of the vesicourethral anastomosis is a serious complication after radical prostatectomy. Strictures occur in 5-8% of patients after radical prostatectomy.

SYMPTOMS

Usually the clinical symptoms include an irritative and obstructive component similar to benign prostatic hyperplasia. In rare cases, patients suffer from partial or complete stress incontinence as a result of the anastomotic stricture.

DIAGNOSTICS

The diagnostic workup is similar to the procedure for urethral strictures. In addition to uroflowmetry, a cystourethrogram (CUG) or, if necessary, a micturating cystourethrogram (MCU) can be performed. A urethrocystoscopy can be performed to ensure the diagnosis.

THERAPY

In most cases, endoscopic procedures were performed for treatment. Beside a transurethral dilation of the stricture or the Sachse urethrotomy, the most common procedure is transurethral resection to treat the stricture. However, all procedures are associated with a high recurrence rate. In recurrent strictures, open surgical procedures, usually a perineal reanastomosis, should performed early.

CONCLUSION

Endourological procedures like transurethral resection are a good treatment option, but due to the high recurrence rates, open surgical procedures should be discussed and if necessary should be performed early.

Systematic single-cell analysis provides new insights into heterogeneity and plasticity of the pancreas

Background

Diabetes mellitus is characterized by loss or dysfunction of insulin-producing β-cells in the pancreas, resulting in failure of blood glucose regulation and devastating secondary complications. Thus, β-cells are currently the prime target for cell-replacement and regenerative therapy. Triggering endogenous repair is a promising strategy to restore β-cell mass and normoglycemia in diabetic patients. Potential strategies include targeting specific β-cell subpopulations to increase proliferation or maturation. Alternatively, transdifferentiation of pancreatic islet cells (e.g. α- or δ-cells), extra-islet cells (acinar and ductal cells), hepatocytes, or intestinal cells into insulin-producing cells might improve glycemic control. To this end, it is crucial to systematically characterize and unravel the transcriptional program of all pancreatic cell types at the molecular level in homeostasis and disease. Furthermore, it is necessary to better determine the underlying mechanisms of β-cell maturation, maintenance, and dysfunction in diabetes, to identify and molecularly profile endocrine subpopulations with regenerative potential, and to translate the findings from mice to man. Recent approaches in single-cell biology started to illuminate heterogeneity and plasticity in the pancreas that might be targeted for β-cell regeneration in diabetic patients.

Scope of review

This review discusses recent literature on single-cell analysis including single-cell RNA sequencing, single-cell mass cytometry, and flow cytometry of pancreatic cell types in the context of mechanisms of endogenous β-cell regeneration. We discuss new findings on the regulation of postnatal β-cell proliferation and maturation. We highlight how single-cell analysis recapitulates described principles of functional β-cell heterogeneity in animal models and adds new knowledge on the extent of β-cell heterogeneity in humans as well as its role in homeostasis and disease. Furthermore, we summarize the findings on cell subpopulations with regenerative potential that might enable the formation of new β-cells in diseased state. Finally, we review new data on the transcriptional program and function of rare pancreatic cell types and their implication in diabetes.

Major conclusion

Novel, single-cell technologies offer high molecular resolution of cellular heterogeneity within the pancreas and provide information on processes and factors that govern β-cell homeostasis, proliferation, and maturation. Eventually, these technologies might lead to the characterization of cells with regenerative potential and unravel disease-associated changes in gene expression to identify cellular and molecular targets for therapy.

[Urethral stricture : From diagnostics to appropriate treatment]

Before making a treatment decision for patients presenting with a urethral stricture, following anamnesis and general examinations, appropriate diagnostics are necessary. This includes at least uroflowmetry and cystourethrography and the use of ultrasound and cystoscopy may be of additional help. The curative treatment of a urethral stricture is always an operation. Besides endourological procedures, open surgery for urethral reconstruction is also performed. This article aims to give an overview about the necessary diagnostic measures and the pros and cons of the different operative therapies.

[Urinary tract infections in children]

Urinary tract infections (UTI) are the most common bacterial infections in children. The symptoms are not very specific and range from abdominal pain, poor feeding to nocturnal urinary incontinence. The technique of collecting urine plays an important role for securing the diagnosis. The best way to obtain urine in non-toilet-trained children is catheterization or suprapubic bladder aspiration. In toilet-trained children midstream urine is an acceptable alternative after cleaning the foreskin or labia. In the case of an infection a prompt empirical antibiotic therapy is necessary to reduce the risk of parenchymal scarring of the kidneys. There are different approaches to diagnose vesicoureteral reflux in different countries. The commonly used standard approach in Germany is voiding cystourethrography. In the case of reflux dimercaptosuccinic acid (DMSA) scintigraphy should be performed additionally to exclude renal scarring (bottom-up approach).

[Vesico-ureteral reflux: Diagnosis and treatment recommendations]

BACKGROUND

Vesico-ureteral reflux (VUR) is one of the most common urologic diseases in childhood. About every third child that presents with a urinary tract infection (UTI) has urinary reflux to the ureter or kidney. Demonstration of a backflow of urine into the ureters or kidneys proves vesicoureteral reflux. In unclear cases, a positioned instillation of contrast agent (PIC) cystogram might be performed and is able to prove vesico-ureteral reflux.

OBJECTIVES

Since low-grade VUR has a high probability of maturation and self-limitation, infants with VUR should be given prophylactic antibiotics during their first year of life, reevaluating the status of VUR after 12 months. The aim of any treatment is to prevent renal damage.

THERAPY

The individual risk of renal scarring is decisive for the choice of adequate therapy. This risk is mainly dependent on reflux grade, age, and gender of the child as well as parental therapy adherence. In principle, therapeutic options include conservative as well as endoscopic or open surgical antireflux therapies.

CONCLUSION

Decisions on treatment should be made individually with parents taking into account all the findings available.

[Localized intermediate- to high-risk prostate cancer]

BACKGROUND

National and international guidelines recommend radical prostatectomy (RP) and radiotherapy (EBRT) as standard treatment for intermediate- and high-risk prostate cancer. Survival benefit of RP in prostate cancer has been proven in prospectively randomized trials. In contrast, the benefit of EBRT as well as the direct comparison of EBRT and RP have been investigated in several retrospective analyses, but are limited by typical problems associated with retrospective studies.

RESULTS

Most of the studies comparing RP with EBRT favor RP with regard to overall survival and cancer-specific survival. Especially in young patients with high-grade prostate cancer, RP seems to be superior in comparison with EBRT. These patient are at high risk of a PSA recurrence and subsequently need an additional radiotherapy. Mortality and morbidity related to these both methods are low. Main complications of RP are urinary incontinence and erectile dysfunction. In contrast, rectal sequelae, erectile dysfunction, and irritative urinary symptoms are the main cause for postinterventional morbidity in patients after EBRT.

[Scrotal space-occupying lesions]

Palpable scrotal masses are common scenarios in any clinical practice. These tumors can be painful or painless, can be intratesticular or extratesticular and be cystic or solid. The distinction between benign and malignant tumors is of utmost importance to enable an adequate and differentiated therapy of patients. In clinical diagnostics besides the medical history, examination of the inguinoscrotal region, laboratory diagnostics and ultrasound examination of the inguinoscrotal area play a decisive role. During the last few years the increased use of contrast-enhanced ultrasound has helped clinicians in differentiating scrotal tumors. Malignant tumors are of particular importance because this entity is the most frequent malignant disease among younger men and according to the Robert Koch Institute there are approximately 3900 new patients in Germany each year (Robert Koch Institute, Krebs in Deutschland 2007/2008 and 2012).

[Organ and function preservation in urethral cancer]

Primary urethral carcinomas are rare tumors that can occur both in men and women. Histological patterns of these tumors are mixed, urothelial tumors occur as well as squamous cell tumors or adenocarcinomas.There are different clinical factors that define clinical prognosis, and the 1- and 5-year cancer-free survival is 75% and 54%. Therapy of locally limited disease is surgical resection, and organ-preserving treatment is possible if negative frozen sections prove complete surgical resection. However, in men a perineal urethrostomy might be necessary, and in women there is a high risk of urinary incontinence if more than 2 cm of the distal urethra is resected.In case of locally advanced tumors or tumors of the proximal urethra, a radical urethrectomy with supravesical urinrary diversion is necessary. In some cases neoadjuvant (radio-)chemotherapy may be an option.

[Prepuce as free transplant]

Graft urethroplasty using free transplants has become a standard procedure in the therapy of complicated urethral strictures. Various types of tissues can be used as graft material and different criteria are important for the suitability of tissues for urethroplasty. It was recognized early on that the prepuce was an easy to harvest tissue with low morbidity and excellent functional results. In this article the suitability of this tissue for functional results will be discussed within the context of the biology of free transplants and the available literature.

Malnutrition and clinical outcome in urological patients

Introduction

In a previous study we evaluated the risk for malnutrition among urological patients in a German university hospital. There are published different studies in other surgical fields that could show a correlation between malnutrition and clinical outcome. As data on this issue is still rare in the urological field we aimed to correlate the risk of malnutrition with different parameters regarding clinical outcome.

Methods

In the time from 2007 to 2009 a total of 320 patients were evaluated regarding the risk of malnutrition and occurrence of complications during the time of hospitalization at our Urological department. The Nutritional risk screening 2002 (NRS) by Kondrup et al. was used for the estimation of the risk level for malnutrition. Patients of a German university hospital were included independently of intervention, age or gender. Parameters for clinical outcome were: pulmonary complications (infectious/noninfectious), cardiovascular complications (infectious/noninfectious), other infections (urinary tract infection etc.), wound healing disorders and time of hospitalization.

Results

In this evaluation 320 patients were included for analysis. Forty patients (13%) presented with a normal nutritional status (NRS score 0) at the time of admission to the hospital and 212 patients (66%) were at risk for forming malnutrition problems (NRS score 1-2). sixty eight patients (21%) of this urological cohort were detected with a malnutrition according to the applied NRS score (≥3). Regarding the occurrence of overall complications in this cohort the rate was rather low compared to other surgical fields. Of 320 patients only 22 patients (7%) presented with relevant complications during their hospitalization. However if data were stratified for peri- and postoperative complications in correlation to nutritional status of patients, an evident trend to a higher complication rate of 9% was obvious.

Conclusions

In our cohort of exclusively urological patients, the risk for post-surgical complications was higher in patients who were malnourished as defined using the Nutritional Risc Screening System (NRS) by Kondrup et al. Further studies need to show whether an adequate nutritional supportive therapy could help to optimize the clinical outcome of malnourished urological patients.

[Open urethral surgery in women]

There are only a few disorders of the female urethra which have to be treated by open urethral surgery, urethral diverticula and urethral strictures. These diseases are rare and subsequently open surgery of the female urethra is also rare. However, these surgical techniques are an important part of the surgical armamentarium in urology, because this is the only method to preserve quality of life of patients concerned. Surgical therapy of urethral diverticula includes well-defined procedures, such as marsupialization and diverticula excision. In contrast, there is no established surgical therapy for female urethral strictures. Several suggestions to solve this problem have been made in recent years and will be presented in this article.

Optical coherence tomography for bladder cancer -- ready as a surrogate for optical biopsy? Results of a prospective mono-centre study

INTRODUCTION

New modalities like Optical Coherence Tomography (OCT) allow non-invasive examination of the internal structure of biological tissue in vivo. The potential benefits and limitations of this new technology for the detection and evaluation of bladder cancer were examined in this study.

MATERIALS AND METHODS

Between January 2007 and January 2008, 52 patients who underwent transurethral bladder biopsy or TUR-BT for surveillance or due to initial suspicion of urothelial carcinoma of the bladder were enrolled in this study. In total, 166 lesions were suspicious for malignancy according to standard white light cystoscopy. All suspicious lesions were scanned and interpreted during perioperative cystoscopy using OCT. Cold cup biopsies and/or TUR-B was performed for all these lesions. For this study we used an OCT-device (Niris, Imalux, Cleveland, US), that utilizes near-infrared light guided through a flexible fibre-based applicator, which is placed into the bladder via the working channel of the cystoscope. The technology provides high spatial resolution on the order of about 10-20 microm, and a visualization of tissue to a depth of about 2 mm across a lateral span of about 2 mm in width. The device used received market clearance from the FDA and CE approval in Germany. The diagnostic and surgical procedure was videotaped and analyzed afterwards for definitive matching of scanned and biopsied lesion. The primary aim of this study was to determine the level of correlation between OCT interpretation and final histological result.

RESULTS

Of 166 scanned OCT images, 102 lesions (61.4%) matched to the same site where the biopsy/TUR-BT was taken according to videoanalysis. Only these video-verified lesions were used for further analysis. Of all analyzed lesions 88 were benign (inflammation, edema, hyperplasia etc.) and 14 were malignant (CIS, Ta, T1, T2) as shown by final histo?pathology. - All 14 malignant lesions were detected correctly by OCT. Furthermore all invasive tumors were staged correctly by OCT regarding tumor growth beyond the lamina propria. There were no false negative lesions detected by OCT. Sensitivity of OCT for detecting the presence of a malignant lesion was 100% and sensitivity for detection of tumor growth beyond the lamina propria was 100% as well. Specificity of OCT for presence of malignancy was 65%, due to the fact that a number of lesions were interpreted as false positive by OCT.

CONCLUSION

As a minimally invasive technique, OCT proved to have extremely high sensitivity for detection of malignant lesions as well as estimation of whether a tumor has invaded beyond the lamina propria. However, specificity of OCT within the bladder was impaired (65%), possibly due to a learning curve and/or the relatively low spatial resolution and visualization depth of the OCT technology. Further studies and technical development are needed to establish an adequate surrogate for optical biopsy.

Perioperative search for circulating tumor cells in patients undergoing radical cystectomy for bladder cancer

Objective

Despite having an organ confined tumor stage at the time of radical cystectomy, a certain number of bladder cancer patients will develop local or distant metastases over time. Currently there are no reliable serum markers for monitoring and evaluating risk profiles of urothelial cancers. Several studies suggest that detection of Circulating Tumor Cells (CTC) may correlate with disease status and prognosis at baseline and early in the treatment of cancers. The presence of CTCs in whole blood before and during radical cystectomy could provide further information on disease status, and could be used as an indicator to determine the need for adjuvant or even perioperative chemotherapy.

Methods

From 03/2009 to 05/2009, five patients with histologically proven transitional cell carcinoma of the urinary bladder participated in this study. All patients were admitted to the hospital for radical cystectomy (rCx). A standard or extended lymph node dissection was performed in all cases. Preoperative CT or MRI scans revealed no distant or local metastases. Median age was 66.8 years (55-81 yrs). After obtaining informed consent from each patient, approximately 30 mL of peripheral blood was taken immediately before rCx and again during surgical removal of the urinary bladder from the patients' body. As additional parameters, operation time (OR) for surgical removal of the bladder and the amount of blood volume that was used for the detection of CTCs were recorded. Obtained blood samples were processed using the Cell-Search System (Veridex^©) within 48 hours of collection. CTCs were identified and quantitated using the Cell-Search System, followed by re-evaluation of the provided results by specially trained and experienced personal. (CS, SH)

Results

CTCs were detected before and during surgical removal of the urinary bladder in one of five patients (20%). In the one patient positive for CTC, two CTCs were detected in the blood sample that was obtained before surgery (analyzed blood volume was 25 mL). There was one CTC detected in the blood sample that was obtained during surgical removal of the urinary bladder (analyzed blood volume was 27 mL). There was no rise in the amount of CTCs during surgical procedure. The final pathological report of this patient showed an advanced tumor stage (T3b, N0, R1). In the other patients, no CTCs were detected at all, neither before rCX nor right after surgical removal of the bladder. Pathological stage for these patients ranged from pT1m G3 -pT2b G3. None of these patients showed lymph node involvement. An average of 14.6 lymph nodes (5-40 LNs) were obtained. OR time to surgical removal of the urinary bladder ranged from 60 minutes to 150 minutes (mean 82 min.).

Conclusions

Although only a very small group of patients was analyzed in this study, the presence of CTCs seems to be correlated with an advanced tumor stage. Therefore the detection of CTCs could be used for an optimized assessment of a patient's disease status in urothelial cancer. A further aim of this study was to assess whether surgical manipulation during radical cystectomy is associated with a release of CTCs into the vascular system. None of the patients who were negative for CTCs before surgery showed CTCs during surgical removal of the bladder, suggesting that there was no release of CTCs during surgery. However, further study is needed to prove these findings and evaluate the significance of CTCs as an indicator for therapeutic decisions.

Conservative management of rectal perforation after nerve sparing endoscopic extraperitoneal radical prostatectomy (nsEERPE) in a patient with a past history of polypectomy

Introduction

Rectal polypectomy causes thinning (or even perforation) of the rectal wall in addition to thermic injury at the polypectomy site.

Case report

We present a rare case of spontaneous rectal perforation after uncomplicated nerve sparing endoscopic extraperitoneal radical prostatectomy in a patient with a previous history of rectal polypectomy at the perforation site. The patient could be treated conservatively. There was complete healing of the fistula without any effect on functional results. This Conservative therapy for such rectal perforations is indicated if the patient's general condition remains stable without any signs of infection.

Conclusions

Polypectomy is an important risk factor for rectal perforation during nsEERPE. Adequate time interval should be given to allow healing and avoid adding further thermal wall damage which may obscure healing leading to complications like fistula. Conservative therapy for small missed rectal perforations constitutes an attractive, feasible and non invasive treatment entity. Following this principle we have not faced this complication in following similar cases.

Verletzungen des Nierenbeckens und des Ureters

About 5% of injuries of the urinary tract affect the renal pelvis and ureter and constitute a severe complication. Around 75% of these injuries are iatrogenic and only about 25% are caused by blunt abdominal trauma or perforation. To avoid complications and improve prognosis, immediate diagnosis and therapy are essential. The diagnostic accuracy of preoperative studies is low, therefore frequently injuries are detected during explorative laparotomy. The management of upper urinary tract lesions depends on severity and localization, whereas the ultimate ambition should always be the preservation of the kidney. As a basic rule, ureteral stenting is mostly sufficient for small lesions, and only larger injuries require open reconstructive techniques. Longitudinal studies document a high degree of functional reconstitution if adequate and immediate treatment is carried out.

[Fluorescence cytology. Improvement of urinary cytology]

Urothelial cancer of the bladder is a frequent disease, and urinary cytology often is used as a routine diagnostic tool. But this technique has an impaired sensitivity in low-grade tumours, and as a subjective method it is highly dependent on the experience of the cytologist. Here we present the technique of fluorescence cytology as an improvement of conventional cytology. This method is potentially able to compensate for the disadvantages of urinary cytology as it is an automated process that uses the principles of 5-Ala-induced photodynamic diagnosis (PDD).

[Scrotal masses]

Any intrascrotal space-consuming process needs to be investigated without delay. The risk of the lesion being a malignant tumor can be assessed on the basis of the differential diagnoses and investigative procedures described herein. If there is the slightest suspicion that the patient has a testicular malignancy he must be immediately referred to a specialist who will investigate any unclear space-consuming lesion by exposing the testis via an inguinal incision. Immediate treatment of a testicular tumor is of decisive importance for the patient's prognosis.

[Urine cytology and urine markers. Significance for clinical practice]

Urothelial carcinoma of the bladder is a frequent disease that can be identified timely by screening patients at high risk. Due to the high rate of disease recurrence, frequent follow-up procedures are necessary. For this purpose, cystoscopy is the standard procedure, and supplementary non-invasive procedures such as cytology or tumor marker tests are used. These tests have different advantages and disadvantages in terms of their sensitivities and specificities. Thus, they provide additional information, but are not able to replace cystoscopy as the standard instrument in the diagnosis of bladder cancer.

[Urinary cytology. Possibilities, limitations and the future]

Even now, 60 years after the fundamental studies on oncological urinary cytology carried out by Papanicolaou and Marschall and the subsequent integration of the test they devised into the diagnostic investigations applied in the diagnosis of urothelial carcinoma, urinary cytology still maintains its place in the diagnosis of primary and recurrent tumours of the urinary tract. Newer diagnostic techniques involving urine-bound tumour markers have not so far achieved such high levels of acceptance as their method. It is possible, certainly, that a combination of these newer methods with cytological testing, or with other innovative diagnostic methods, such as photodynamic techniques, could prove very promising in the future and might overcome the limitations of urinary cytology.

Macrophage activation in type 1 diabetic patients with catheter obstruction during peritoneal insulin delivery with an implantable pump

OBJECTIVE

The purpose of this study was to evaluate the activation of macrophages in type 1 diabetic patients during peritoneal insulin delivery with an implantable pump against two types of insulin: that which was collected from the pump reservoir and that which came straight fromn the bottle (i.e., vial insltlin). Macrophage activation was studied in patients with and without cathcter obstruction and compared with activation in healthy subjects.

RESEARCH DESIGN AND METHODS

Human insulin (21 PH, 400 U/ml; Hoescht) was collected from the pump reservoir (Minimed) of diabetic patients with (n = 3) or without (n = 7) catheter obstruction, as assessed by histological examination of the catheter tip. Monocytes were obtained from venous blood samples from both kinds of diabetic patients and from healthy subjects (n = 5) and were differentiated into monocyte-derived macrophages in culture. Their chemotaxis and tumor necrosis factor-alpha (TNF-alpha) release were studied with respect to both types of insulin, as previously stated. Formyl-methionyl-leucyl-phenylalanine (fMLP) and lipopolysaccharide (LPS) were used as controls.

RESULTS

Neither insulin recovered from the pump reservoir nor vial insulin proved chemotactic to macrophages from either healthy subjects or those diabetic patients with and without catheter obstruction. The migration toward fMLP of macrophages from patients presenting a catheter obstruction was significantly higher than that observed with macrophages from either diabetic patients without obstruction or healthy subjects, the chemotactic index (mean +/- SD) was 3.81 +/- 0.36 vs. 2.30 +/- 0.89 and 2.60 +/- 0.80, respectively (P < 0.05). LPS significantly stimulated the TNF-alpha secretion of macrophages from diabetic subjects with a catheter obstruction, whereas both native and reservoir-recovered insulin had no effect on this release (144.83 +/- 67.25 vs. 5.15 +/- 2.93 and 5.27 +/- 2.43 pg/ml, P < 0.001).

CONCLUSIONS

The human insulin used in implantable pumps, regardless of how long it had remained in the pump reservoir, did not induce macrophage activation in diabetic patients treated through intraperitoneal insulin delivery. In some of these diabetic patients, catheter obstruction could be explained by their high capacity of macrophage chemotaxis.

Chemotaxis activation of peritoneal murine macrophages induced by the transplantation of free and encapsulated pancreatic rat islets

The present study concerns the influence of the transplantation of free and encapsulated (AN69 membrane, Hospal) islets on the chemotaxis of peritoneal macrophages. Fifty free or encapsulated rat islets, cultured for 24 h, were transplanted in the peritoneal cavity of mice (n = 12). Three days after transplantation, the chemotaxis of peritoneal murine macrophages was tested towards formyl-methionyl-leucyl-phenylalanine (fMLP) and a culture medium conditioned for 3 days by free rat islets isolated from the same rat donor. In response to fMLP, the chemotactic indexes of macrophages from mice transplanted with free or encapsulated islets were 8.09 +/- 2.10 and 9.45 +/- 2.76, respectively. These values were significantly higher than those obtained when macrophages from untreated mice were tested (2.42 +/- 0.23; p < 0.01). In response to culture medium conditioned by free islets, the transplanted encapsulated islets failed to enhance macrophage chemotaxis (2.41 +/- 0.53) compared to transplanted free islets (7.00 +/- 2.63; p < 0.01). Thus, encapsulation decreased the specific chemotactic activity of peritoneal macrophages induced by free islet transplantation, probably by prohibiting the diffusion of chemoattractants.

Chemotactic activity of culture supernatants of free and encapsulated pancreatic rat islets towards peritoneal macrophages

Longterm efficiency of encapsulated pancreatic islet transplantation is limited by macrophagic reaction at the surface of biocompatible membrane. The aim of this work was to investigate the influence of soluble factors released by free and encapsulated islets on macrophage chemotaxis. The culture mediums conditioned for 6 days by free and encapsulated rat islets were incubated with peritoneal murine, rat allo and syngenic macrophages to study their migration. Culture supernatants of rat fibroblasts and acinar cells, glucose-stimulated free rat islets and supernatants of free rat islets treated by heat and proteinase K were also tested for their chemotactic activity. Islets encapsulation decreased the chemotactic activity of culture medium conditioned for 6 days by free rat islets on murine (1.66 +/- 0.20 vs. 3.10 +/- 0.23; p < 0.001, n = 5) and rat allogenic macrophages (1.63 +/- 0.21 vs. 4.70 +/- 0.36; p < 0.001, n = 9). There was no migration of rat macrophages towards syngenic islets. Fibroblasts exhibited a very strong chemotactic effect as compared to acinar cells. Insulin was not involved in macrophage migration. Proteinase K treatment of culture supernatant of free rat islets totally inhibited the chemotactic activity. After heating at 56 degrees C and 100 degrees C, this activity was reduced to 41 +/- 7% and 32 +/- 5% of the initial activity, respectively. In conclusion, pancreatic islet stimulated macrophage migration by release of immunological specific proteins partly retained by macroencapsulation.