The Urinary Tract Microbiome in Male Genitourinary Diseases: Focusing on Benign Prostate Hyperplasia and Lower Urinary Tract Symptoms

The human microbiome and benign prostatic hyperplasia: Current understandings and clinical implications

The research of the human microbiome in the preceding decade has yielded novel perspectives on human health and diseases. Benign prostatic hyperplasia (BPH) is a common disease in middle-aged and elderly males, which negatively affects the life quality. Existing evidence has indicated that the human microbiome, including urinary, intra-prostate, gut, oral and blood microbiome may exert a significant impact on the natural progression of BPH. The dysbiosis of the microbiome may induce inflammation at either a local or systemic level, thereby affecting the BPH. Moreover, metabolic syndrome (MetS) caused by the microbiome can also be involved in the development of BPH. Additionally, alterations in the microbiome composition during the senility process may serve as another cause of the BPH. Here, we summarize the influence of human microbiome on BPH and explore how the microbiome is linked to BPH through inflammation, MetS, and senility. In addition, we propose promising areas of investigation and discuss the implications for advancing therapeutic approaches.

The effects of radiation on myeloid lineage immune cells within the rodent urinary bladder: a systematic review

PURPOSE

Radiotherapy is a prominent therapy for many malignant and non-malignant disorders, though it can cause side effects such as radiation-induced cystitis. Current research has highlighted a role for mast cells and macrophages in the prognosis of such radiation-induced toxicities. However, the prognostic value of these immune cells in the pathophysiology of radiation-induced cystitis is not clear. As such, a systematic review was conducted to assess myeloid-lineage immune cells for their prognostic value in radiation-induced cystitis to address this gap in literature.

METHODS

The protocol was registered in PROSPERO, and searches were performed in PubMed, Embase and Web of Science databases for pre-clinical rodent studies on radiation-induced cystitis.

RESULTS

After de-duplication, 153 articles were screened for relevancy by title and abstract. Title and abstract screening deemed 64 studies irrelevant. The remaining 85 studies were full-text screened, yielding seven unique articles for data extraction. Most included studies had an unclear risk of bias. The findings of this systematic review suggest that the prognostic value of myeloid-lineage immune cells in radiation-induced cystitis is still unclear, indicating a need for further research in this field.

CONCLUSION

Although the studies reviewed provide some insight into the role of these immune cells in disease pathology, the limited number of studies and unclear risk of bias further highlights a need for additional, high-quality research in this area. In summary, this systematic review highlights a need to understand the involvement of immune cells in radiation-induced cystitis pathophysiology and lay the groundwork for further research in this area.

TRIAL REGISTRATION

PROSPERO registration: CRD42022345960.

Urinary tract infection in patients with lower urinary tract dysfunction

Lower urinary tract dysfunction (LUTD) is becoming more common in aging societies worldwide. In patients with LUTD, the risk of urinary tract infection (UTI) rises due to several distinct mechanisms, including easy bacterial access to the urinary tract, impaired bacterial washout, and an impaired innate defense system. The pathophysiology of LUTD varies depending on whether it is neurogenic or non-neurogenic, as well as by gender; therefore, the etiology and characteristics of UTI differ according to the type of LUTD. Patients with neurogenic LUTD, especially those with spinal cord injury, have a high risk of febrile UTI, and strict bladder management is required to prevent UTI. Clean intermittent catheterization with or without appropriate pharmacological therapy is also strongly recommended for patients with neurogenic LUTD at risk of febrile UTI, unable to void, or with high post-void residual volume. In contrast, both male and female patients with non-neurogenic LUTD have a lower risk of symptomatic UTI. There is insufficient evidence for non-neurogenic LUTD regarding the association between symptomatic UTI but not asymptomatic bacteriuria and LUTD severity, including the presence of post-void residual volume, or whether therapeutic intervention for LUTS reduces the incidence of UTI, particularly in male patients. In this narrative review, we aimed to highlight the pathogenesis, epidemiology, and management of UTI in patients with LUTD.

Studies of ultrastructure, gene expression, and marker analysis reveal that mouse bladder PDGFRA+ interstitial cells are fibroblasts

Fibroblasts are crucial to normal and abnormal organ and tissue biology, yet we lack basic insights into the fibroblasts that populate the bladder wall. Candidates may include bladder interstitial cells (also referred to as myofibroblasts, telocytes, and interstitial cells of Cajal-like cells), which express the fibroblast-associated marker PDGFRA along with VIM and CD34 but whose form and function remain enigmatic. By applying the latest insights in fibroblast transcriptomics, coupled with studies of gene expression, ultrastructure, and marker analysis, we observe the following: 1) that mouse bladder PDGFRA+ cells exhibit all of the ultrastructural hallmarks of fibroblasts including spindle shape, lack of basement membrane, abundant endoplasmic reticulum and Golgi, and formation of homotypic cell-cell contacts (but not heterotypic ones); 2) that they express multiple canonical fibroblast markers (including Col1a2, CD34, LY6A, and PDGFRA) along with the universal fibroblast genes Col15a1 and Pi16 but they do not express Kit; and 3) that PDGFRA+ fibroblasts include suburothelial ones (which express ACTA2, CAR3, LY6A, MYH10, TNC, VIM, Col1a2, and Col15a1), outer lamina propria ones (which express CD34, LY6A, PI16, VIM, Col1a2, Col15a1, and Pi16), intermuscular ones (which express CD34, VIM, Col1a2, Col15a1, and Pi16), and serosal ones (which express CD34, PI16, VIM, Col1a2, Col15a1, and Pi16). Collectively, our study revealed that the ultrastructure of PDFRA+ interstitial cells combined with their expression of multiple canonical and universal fibroblast-associated gene products indicates that they are fibroblasts. We further propose that there are four regionally distinct populations of fibroblasts in the bladder wall, which likely contribute to bladder function and dysfunction.NEW & NOTEWORTHY We currently lack basic insights into the fibroblasts that populate the bladder wall. By exploring the ultrastructure of mouse bladder connective tissue cells, combined with analyses of their gene and protein expression, our study revealed that PDGRA+ interstitial cells (also referred to as myofibroblasts, telocytes, and interstitial cells of Cajal-like cells) are fibroblasts and that the bladder wall contains multiple, regionally distinct populations of these cells.

The Potential Role of Urinary Microbiome in Benign Prostate Hyperplasia/Lower Urinary Tract Symptoms

Historically, urine in the urinary tract was considered “sterile” based primarily on culture-dependent methods of bacterial detection. Rapidly developing sequencing methods and analytical techniques have detected bacterial deoxyribonucleic acid and live bacteria in urine, improving our ability to understand the urinary tract microbiome. Recently, many studies have revealed evidence of a microbial presence in human urine in the absence of clinical infections. In women, fascinating evidence associates urinary tract microbiota with lower urinary tract symptoms (LUTS). However, the association between urinary tract microbiota and men with LUTS, particularly those with benign prostate hyperplasia (BPH), has not been established. In addition, the identification of the proinflammatory cytokines and pathogens responsible for the clinical progression of BPH is still underway. This review article aimed to address microbiome-related evidence for BPH. Further studies are required for a comprehensive understanding of the relationship between the urogenital microbiome and BPH pathogenesis to facilitate the development of preventive and therapeutic approaches for male LUTS.

The Urogenital System’s Role in Diseases: A Synopsis

Simple Summary

The urinary tract microbiome has come under a lot of scrutiny, and this has led to the rejection of the pre-established concept of sterility in the urinary bladder. Microbial communities in the urinary tract have been implicated in the maintenance of health. Thus, alterations in their composition have also been associated with different urinary pathologies, such as urinary tract infections. For that reason, tackling the urinary microbiome of healthy individuals, as well as its involvement in disease through the proliferation of opportunistic pathogens, could open a potential field of study, leading to new insights into prevention, diagnosis, and treatment strategies for different diseases.

Abstract

The human microbiota contains ten times more microbial cells than human cells contained by the human body, constituting a larger genetic material than the human genome itself. Emerging studies have shown that these microorganisms represent a critical determinant in human health and disease, and the use of probiotic products as potential therapeutic interventions to modulate homeostasis and treat disease is being explored. The gut is a niche for the largest proportion of the human microbiota with myriad studies suggesting a strong link between the gut microbiota composition and disease development throughout the body. More specifically, there is mounting evidence on the relevance of gut microbiota dysbiosis in the development of urinary tract disease including urinary tract infections (UTIs), chronic kidney disease, and kidney stones. Fewer emerging reports, however, are suggesting that the urinary tract, which has long been considered ‘sterile’, also houses its unique microbiota that might have an important role in urologic health and disease. The implications of this new paradigm could potentially change the therapeutic perspective in urological disease.

Molecular Regulatory Mechanisms Drive Emergent Pathogenetic Properties of Neisseria gonorrhoeae

Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection (STI) gonorrhea, with an estimated 87 million annual cases worldwide. N. gonorrhoeae predominantly colonizes the male and female genital tract (FGT). In the FGT, N. gonorrhoeae confronts fluctuating levels of nutrients and oxidative and non-oxidative antimicrobial defenses of the immune system, as well as the resident microbiome. One mechanism utilized by N. gonorrhoeae to adapt to this dynamic FGT niche is to modulate gene expression primarily through DNA-binding transcriptional regulators. Here, we describe the major N. gonorrhoeae transcriptional regulators, genes under their control, and how these regulatory processes lead to pathogenic properties of N. gonorrhoeae during natural infection. We also discuss the current knowledge of the structure, function, and diversity of the FGT microbiome and its influence on gonococcal survival and transcriptional responses orchestrated by its DNA-binding regulators. We conclude with recent multi-omics data and modeling tools and their application to FGT microbiome dynamics. Understanding the strategies utilized by N. gonorrhoeae to regulate gene expression and their impact on the emergent characteristics of this pathogen during infection has the potential to identify new effective strategies to both treat and prevent gonorrhea.

The Urobiome and Its Role in Overactive Bladder

Urine is no longer considered to be sterile. After the existence of the microbiome was revealed through metagenomic analysis using next-generation sequencing, the relationship between characteristics of the microbiome and diseases have been studied and published in various journals. A microbiome exists in the urinary tract and is associated with urinary tract infection, malignancy of the genitourinary tract, and lower urinary tract symptoms. Based on the urine sampling method, sampling site, culture method, and sex, the characteristics of the microbiome vary. Most of the Lactobacillus species are identified mainly in women, and various other species are identified in men. These microorganisms can cause or prevent various diseases. Variations in the microbiome are seen in those with and without disease, and an asymptomatic status does not indicate the absence of microbes. This microbiome has been implicated in a variety of lower urinary tract symptoms and diseases, in particular, overactive bladder. The microbiome differs between patients with urgency and urge urinary incontinence and healthy individuals. There are many aspects of the microbiome yet to be studied in relation to other lower urinary tract symptoms.

Assessment of Bacterial Communities Within the Biofilm of Bladder Calculi in the Neurogenic Bladder Rat Model Following Spinal Cord Injury

Purpose: To develop a rat model of bladder calculi in the neurogenic bladder following spinal cord injury (SCI) and assess bacterial communities within the biofilm of bladder calculi using denaturing gradient gel electrophoresis (DGGE).Methods: The silk tied to a small segment of the Teflon IV catheter was implanted through the urethra into the bladder of rats with SCI induced by T9 laminectomy. After 6 months, the rats were sacrificed and their bladder calculi were collected by opening the bladders through the low-midline incision. Genomic DNA was extracted from the biofilm of bladder calculi followed by DGGE to obtain bacterial DNA. The DNA sequences were compared and analyzed using BLAST (Basic Local Alignment Search Tool) to identify bacteria.Results: After placing silk nidus in the bladder for 6 months, all 6 rats developed bladder calculi. According to DGGE analysis, Pseudomonas aeruginosa was the most dominant strain, while Clostridium sp. and Lactobacillus sp. were relatively dominant strains within the biofilm of bladder calculi in the rats with SCI.Conclusions: DGGE analysis showed various microorganisms in the biofilm of calculi arising from a neurogenic bladder rat model. This research design can be the basis for clinical studies and may be applied to calculi in patients with neurogenic bladder following SCI.

A Cross-Sectional Study for Association between Periodontitis and Benign Prostatic Hyperplasia Using the Korean Genome and Epidemiology Study Data

Recently, several studies have suggested the relationship between periodontitis and prostatic disease. However, epidemiological studies on the association between periodontitis and benign prostatic hyperplasia (BPH) are scarce. Hence, we aimed to identify the association between the two diseases using data from the Korean Genome and Epidemiology Study. Among the 173,209 participants, 3297 men with periodontitis and 35,292 controls (without periodontitis) were selected. The history of BPH in participants with periodontitis and the controls were also investigated. Two-tailed analyses, independent t-tests, and chi-square tests were used for statistical analysis. The adjusted odds ratio (OR) for BPH was 1.50 (95% confidence interval, 1.35–1.68; p < 0.001) after adjusting for past medical histories. The adjusted OR for BPH was 1.57 (95% confidence interval, 1.41–1.76; p < 0.001) after adjusting for anthropometric and laboratory data. Collectively, this study provides evidence that periodontitis is associated with BPH. This finding supports the use of regular dental checkups and periodontal treatments to reduce the prevalence and progression of BPH.

Urobiome: An outlook on the metagenome of urological diseases

The urinary tract likely plays a role in the development of various urinary diseases due to the recently recognized notion that urine is not sterile. In this mini review, we summarize the current literature regarding the urinary microbiome and mycobiome and its relationship to various urinary diseases. It has been recently discovered that the healthy urinary tract contains a host of microorganisms, creating a urinary microbiome. The relative abundance and type of bacteria varies, but generally, deviations in the standard microbiome are observed in individuals with urologic diseases, such as bladder cancer, benign prostatic hyperplasia, urgency urinary incontinence, overactive bladder syndrome, interstitial cystitis, bladder pain syndrome, and urinary tract infections. However, whether this change is causative, or correlative has yet to be determined. In summary, the urinary tract hosts a complex microbiome. Changes in this microbiome may be indicative of urologic diseases and can be tracked to predict, prevent, and treat them in individuals. However, current analytical and sampling collection methods may present limitations to the development in the understanding of the urinary microbiome and its relationship with various urinary diseases. Further research on the differences between healthy and diseased microbiomes, the long-term effects of antibiotic treatments on the urobiome, and the effect of the urinary mycobiome on general health will be important in developing a comprehensive understanding of the urinary microbiome and its relationship to the human body.