The role of adrenomedullin in varicocele and impotence

From pathophysiology to practice: addressing oxidative stress and sperm DNA fragmentation in Varicocele-affected subfertile men

Varicocele can reduce male fertility potential through various oxidative stress mechanisms. Excessive production of reactive oxygen species may overwhelm the sperm's defenses against oxidative stress, damaging the sperm chromatin. Sperm DNA fragmentation, in the form of DNA strand breaks, is recognized as a consequence of the oxidative stress cascade and is commonly found in the ejaculates of men with varicocele and fertility issues. This paper reviews the current knowledge regarding the association between varicocele, oxidative stress, sperm DNA fragmentation, and male infertility, and examines the role of varicocele repair in alleviating oxidative-sperm DNA fragmentation in these patients. Additionally, we highlight areas for further research to address knowledge gaps relevant to clinical practice.

Effect of varicocele and varicocelectomy on sperm deoxyribonucleic acid fragmentation rates in infertile men with clinical varicocele

Varicocele is the leading cause of male infertility. It can affect sperm quantity and quality through various non-mutually exclusive pathophysiological mechanisms, mainly oxidative stress. Excessive production of reactive oxygen species may overwhelm the sperm's defenses against oxidative stress and harm the sperm's DNA. Excessive sperm DNA breaks, so-called sperm DNA fragmentation, result from the oxidative stress cascade and are commonly found in the ejaculates of men with varicocele and fertility-related issues. Measuring sperm DNA fragmentation can provide valuable information on the extent of harm and might help select candidates for surgical treatment. Varicocelectomy is beneficial for alleviating oxidative stress-associated infertility and improving sperm DNA integrity. However, reproductive outcomes of infertile men with elevated sperm DNA fragmentation rates and surgically treated varicoceles remain poorly studied, and there is a need for well-designed trials to determine the impact of sperm DNA fragmentation reduction on natural and medically assisted reproduction.

Diagnostic work up: Laboratory and biomarkers

This chapter will focus on the diagnostic work around sexual dysfunction in Parkinson's disease, especially laboratory tests and biomarkers. A number of methods to analyze if sexual dysfunction is caused by neural pathology, vascular dysfunction or other mechanisms are now available. Other methods can be used to differentiate between psychogenic/functional reasons behind sexual dysfunction and organic ones. The role of biomarkers for diagnosis, but also for understanding the reason behind and for counteracting sexual dysfunction is becoming more evident. There is also a rich and increasing number of scales and other instruments available for detecting and quantifying sexual hypo- and hyperactivity. When investigating the reason behind sexual dysfunction in patients with Parkinson's disease comorbidities should also be considered. Finally, early and pronounced sexual dysfunction might in some cases be an indication that differential diagnosis, like Multisystem Atrophy, should be thought about. All these aspects of the diagnostic procedures around sexual dysfunction in Parkinson's disease will be covered in this chapter.

lncRNA and mRNA sequencing of the left testis in experimental varicocele rats treated with Morinda officinalis polysaccharide

Varicocele is a common disease of the male reproductive system. Morinda (M.) officinalis is a Chinese herbal medicine, whose main bioactive component M. officinalis polysaccharide (MOP) is believed to have a therapeutic effect on varicocele; however, the underlying molecular mechanisms of this effect are poorly understood. In the present study, 24 rats were randomly divided into three groups: i) Control group; ii) experimental varicocele group; and iii) 300 mg/kg MOP administration group. Analysis of mRNA and long non-coding RNA (lncRNA) expression in rat left testicular tissue was performed. The results suggested that a total of 144 mRNAs and 63 lncRNAs, 63 mRNAs and 148 lncRNAs, and 173 mRNAs and 54 lncRNAs were differentially expressed between the varicocele non-treatment and control groups, the varicocele treatment and varicocele non-treatment groups, and the varicocele treatment and control groups, respectively. Following validation by reverse transcription-quantitative PCR, the Yip1 domain family member 7 (YIPF7) gene was identified as a key mediator of varicocele pathogenesis and repair effect of MOP. Additionally, genes such as purinergic receptor P2X 4 (P2RX4), transmembrane protein 225B (TMEM255B) and Wnt family member 9B (WNT9B) were confirmed to be differentially expressed between the varicocele non-treatment and control groups. We hypothesize that TMEM255B could be a potential novel diagnostic biomarker for varicocele; WNT9B and P2RX4 likely play notable roles in the pathophysiology of the disease through the Wnt signaling pathway and regulation of transmembrane ion channels, respectively. In summary, the present study delineated the molecular mechanisms underlying varicocele pathogenesis and the therapeutic effect of MOP, identified a potential novel diagnostic marker and therapeutic target for varicocele, and provided feasible directions for further studies in the future.

Disruption of anchoring junctions in the testes of experimental varicocele rats

Varicocele is a common disease of the male reproductive system and is the main cause of male infertility; however, the pathological mechanisms of varicocele remain unclear. The anchoring junctions (AJs) in the testies are located between Sertoli cells, or between Sertoli cells and germ cells. Intact and functional AJs are crucial for spermatogenesis. In the present study, the histomorphology, ultrastructure of AJ, cell cycle, expression of AJ structural proteins, and the level of AJ-associated signaling molecules were investigated in the left testes of experimental varicocele rats at 8 and 12 weeks after surgery. The results revealed that varicocele induced the loss of premature germ cells from the seminiferous epithelium. Furthermore, the results of the present study also revealed damage to the AJ ultrastructure, disorientation of the spermatid head, deregulation of the cell cycle, downregulation of AJ structural proteins, enhanced phosphorylation of focal adhesion kinase (FAK) at Tyr³⁹⁷ and its downstream adapter Src at Tyr⁴¹⁶, and activation of the extracellular signal-regulated protein kinase 1 (ERK1) signaling pathway. Thus, the present study demonstrated that varicocele disrupted the structure and function of AJs in the left testes of rats, and that enhancement of FAK phosphorylation may contribute to AJ damage by activating ERK1 signaling, disrupting actin-based filament networks, and altering the balance of the apical ectoplasmic specialization-blood testis barrier functional axis. These findings provide important insights into the pathological mechanisms through which varicocele contributes to male infertility and could help to identify new therapeutic targets for varicocele.

Perspectives in Pediatric Pathology, Chapter 20. Adolescent Varicocele

Varicocele is characterized by elongation, dilatation, and tortuosity of the veins draining the testis and its covers, causing circulatory reflux along the inner spermatic vein [ 1 ]. Varicocele results in progressive testicular lesions and, if untreated, can lead to testicular atrophy [ 2 ]. Varicocele is considered the most frequently identified cause of male infertility [ 3 ]. The mechanisms involved in varicocele formation are not well known and probably are multiple, differing from one patient to another.

Varicocele management in the era of in vitro fertilization/intracytoplasmic sperm injection

Varicocele is the most common surgically treatable cause of male infertility, and often results in alterations in semen parameters, sperm DNA damage, and changes to the seminal milieu. Varicocele repair can result in improvement in these parameters in the majority of men with clinical varicocele; data supporting repair in men with subclinical varicocele are less definitive. In couples seeking fertility using assisted reproductive technologies (ARTs), varicocele repair may offer improvement in semen parameters and sperm health that can increase the likelihood of successful fertilization using techniques such as in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), or may decrease the level of ART needed to achieve successful pregnancy. Male infertility is an indicator of general male health, and evaluation of the infertile male with an eye toward future health can facilitate optimal screening and treatment of these men. Furthermore, varicocele may represent a progressive lesion, offering an argument for its repair, although this is currently unclear.

Effects of Morinda officinalis Polysaccharide on Experimental Varicocele Rats

Morinda officinalis is a traditional Chinese herbal medicine, which has been used to tonify the kidney and strengthen yang for a long time in China. In this study, the effects of M. officinalis Polysaccharide (MOP) on experimental varicocele adolescent rats were investigated. The result showed that varicocele destroyed the structure of the seminiferous epithelium and decreased the TJ protein expression (Occludin, Claudin-11, and ZO-1), testosterone (T) concentration in the left testicular tissue and serum, and serum levels of inhibin B (INHB), while increasing the levels of cytokines (TGF-β3 and TNF-α) in the left testicular tissue, as well as serum levels of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and antisperm antibody (AsAb). MOP repaired the damaged seminiferous epithelium and TJ and reduced the levels of cytokines (TGF-β3 and TNF-α) as well as serum levels of GnRH, FSH, LH, and AsAb, while upregulating TJ protein expression, T level in the left testicular tissue and serum, and serum INHB levels. In summary, we conclude that MOP promotes spermatogenesis and counteracts the varicocele-induced damage to the seminiferous epithelium and TJ, probably via decreasing cytokines (TGF-β3 and TNF-α) levels and regulating the abnormal sex hormones levels in experimental varicocele rats.

When is a varicocele repair indicated: the dilemma of hypogonadism and erectile dysfunction?

In the past, the indications for varicocelectomy are primarily for infertility with abnormal semen parameters, testicular hypotrophy/atrophy in adolescents, and/or pain. The surgical treatment of varicocele for hypogonadism is controversial and debated. Recently, multiple reports in the literature have suggested that varicocele is associated with hypogonadism and varicocele repair can increase testosterone levels. Men with hypogonadal symptoms should have at least two serum testosterone levels. Microsurgical varicocelectomy may be beneficial for men with clinically palpable varicoceles with documented hypogonadism. In this review, we summarize the most recent literature linking varicocele to hypogonadism and sexual dysfunction and the impact of repair on serum testosterone levels. We performed a search of the published English literature. The key words used were “varicocele and hypogonadism” and “varicocele surgery and testosterone.” We included published studies after 1998. We, also, evaluated the effect of surgery on the changes in the serum testosterone level regardless of the indication for the varicocele repair.

Varicocele and testicular function

Testicular varicocele, a dilation of the veins of the pampiniform plexus thought to increase testicular temperature via venous congestion, is commonly associated with male infertility. Significant study has clarified the negative impact of varicocele on semen parameters and more recent work has shed light on its detrimental effects on the molecular and ultrastructural features of sperm and the testicular microenvironment, as well as more clearly defined the positive impacts of treatment on couples’ fertility. The relationship between varicocele and testicular endocrine function, while known for some time based on histologic evaluation, has become more apparent in the clinical setting with a growing link between varicocele and hypogonadism. Finally, in the pediatric setting, while future study will clarify the impact of varicocele on fertility and testicular function, recent work supports a parallel effect of varicocele in adolescents and adults, suggesting a re-evaluation of current treatment approaches in light of the progressive nature of the condition and potential increased risk of future disease.

The varicocele

Varicoceles are an abnormal dilation of the pampiniform plexus of veins within the scrotum. Varicoceles are highly prevalent and can result in a myriad of deleterious effects on male reproduction. Numerous therapeutic options are available for correcting varicoceles, including surgical varicocelectomy and radiographic venous embolization. Varicocele correction is a more cost-effective therapeutic modality than both intrauterine insemination (IUI) and in vitro fertilization (IVF) for affected couples. In summary, varicoceles contribute significantly to male reproductive pathology, and varicocele correction is an important option for both clinicians and patients to consider in this era of assisted reproductive techniques.

Insight into oxidative stress in varicocele-associated male infertility: part 1

Varicocele is recognized as the leading cause of male infertility because it can impair spermatogenesis through several distinct pathophysiological mechanisms. Current evidence supports oxidative stress as a key element in the pathophysiology of varicocele-related infertility, although these mechanisms have not yet been fully described. Measurement of the reactive oxygen species and other markers of oxidative stress, including the levels of the antioxidant enzymes catalase and superoxide dismutase, can provide valuable information on the extent of oxidative stress and might guide therapeutic management strategies. The testis can respond to varicocele-associated cell stressors, such as heat stress, ischaemia or production of vasodilators (for example, nitric oxide) at the expense of the generation of excessive reactive oxygen species. These responses have their own implications in exacerbating the underlying oxidative stress and on the subsequent infertility.

Treatment strategy for the adolescent varicocele

A varicocele is a dilatation of the testicular vein and the pampiniform venous plexus within the spermatic cord. Although rare in pediatric populations, the prevalence of varicoceles markedly increases with pubertal development. Varicoceles are progressive lesions that may hinder testicular growth and function over time and are the most common and correctable cause of male infertility. Approximately 40% of men with primary infertility have a varicocele, and more than half of them experience improvements in semen parameters after varicocelectomy. The decision to treat adolescents with varicocele is a controversial one. The task for pediatricians and urologists is to identify those adolescents who are at greatest risk for infertility in adulthood, in an effort to offer early surgical intervention to those most likely to benefit.

Adrenomedullin reduces antioxidant defense system and enhances kidney tissue damage in cadmium and lead exposed rats

Adrenomedullin (AdM) is synthesized and secreted by a number of cells and tissue. AdM is a potent vasodilator but it is also considered a neuromodulator, an angiogenic factor, and a hormone regulator. AdM possess antiapoptotic, antioxidant, and antimicrobial properties. Heavy metals such as cadmium and lead are found widely in the environment and they have important biological functions. Lead (Pb) and cadmium (Cd) can accumulate in the lungs, liver, bone, and kidneys and cause serious organ damage. In the present study, we investigated the effect of AdM, Pb + AdM, and Cd + AdM treatments on superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities as well as the level of malondialdehyde (MDA) in the kidney. Heavy metal accumulation was determined in kidney with and without AdM infusion and kidney damage was evaluated by light and electron microscopy. Increased heavy metal accumulation was observed in the heavy metal and AdM treated groups. SOD, CAT, GSH-Px activities, and MDA levels were significantly different in the treatment groups when compared with the control group. Tubular degeneration, necrosis, cell swelling, mononuclear cell infiltration, and degenerated organelles were observed in the kidney following treatment. Therefore, AdM infusion has no beneficial and/or compensatory role in cadmium and lead toxicity in the kidney. We conclude that heavy metal accumulation in the kidney in conjunction with AdM infusion is cytotoxic despite the known beneficial effects of adrenomedullin.

Circulating adrenomedullin levels in ankylosing spondylitis and Familial Mediterranean Fever

INTRODUCTION

Adrenomedullin (AM) is a 52-amino acid peptide with vasorelaxant properties. Apart from its roles on vascular tonus, AM can also contribute to inflammatory events. Plasma AM levels were elevated in connective tissue diseases and vasculitic disorders. Ankylosing spondylitis (AS) is a chronic inflammatory disease of the spine initiating in the sacroiliac joints. Familial Mediterranean Fever (FMF) is a hereditary disorder characterized by self-limiting acute attacks of fever and the presence of sustained subclinical inflammation in the attack-free periods. In this study, we investigated plasma AM levels in patients with AS and patients with FMF.

METHODS

Twenty AS patients with active disease manifestations (mean age: 41.6+/-10.9 years, female/male: 7/13), 28 FMF patients with acute attack (mean age: 27.4+/-10.7 years, female/male: 17/11), and 26 healthy controls (mean age: 39.9+/-5.5 years, female/male: 16/10) were enrolled in this study. AM levels were also measured in 11 FMF patients 2 months after the cessation of their attacks. AM levels of those 11 patients during their FMF attacks and attack-free periods were also compared.

RESULTS

Median plasma AM levels were 23.86 (17.24-40.09) pmol/mL, 27.33 (17.24-38.52) pmol/mL, and 26.11 (17.05-37.42) pmol/mL in AS patients, FMF patients with acute attack, and healthy controls, respectively (p>0.05). AM levels were also similar in the attack-free periods of FMF patients [26.35 (24.35-34.14) pmol/mL]. There was no correlation between plasma AM levels and C-reactive protein, or between plasma AM levels and erythrocyte sedimentation rate.

CONCLUSIONS

AM does not seem to have any role in the pathogenesis of AS and FMF. Previous reports of elevated levels of AM in connective tissue disorders and vasculitic diseases are probably disease specific, and AM does not seem to be a common component of inflammatory rheumatic disorders.

Adrenomedullin: a new and promising target for drug discovery

Adrenomedullin (AM) is a 52 amino acid peptide that plays a critical role in several diseases such as hypertension, cancer, diabetes, cardiovascular and renal disorders, among others. Interestingly, AM behaves as a protective agent against some pathologies, yet is a stimulating factor for other disorders. Thus, AM can be considered as a new and promising target for the design of non-peptidic modulators that could be useful for the treatment of those pathologies, by regulating AM levels or the activity of AM. A full decade on from its discovery, much more is known about AM molecular biology and pharmacology, but this knowledge still needs to be applied to the development of clinically useful drugs.

Adrenomedullin in human male reproductive system

OBJECTIVE

To investigate adrenomedullin (AM) localization and distribution in human male reproductive system and to determine whether seminal fluid AM concentration correlates with sperm parameters.

STUDY DESIGN

Plasma and semen samples (n = 19) obtained from healthy volunteers with normal seminal fluid parameters were assayed for AM using a specific RIA. AM immunostaining was sought on sections of penile cavernous bodies and testicular tissues obtained postmortem from four young males after accidental death using a polyclonal antibody to AM 1-52.

RESULTS

Mean AM concentration in seminal plasma was 209.4+/-46.6 pg/ml, 8-9-fold higher than in circulating plasma and correlated with sperm motility (r = 0.715, p < 0.01). Endothelial cells of cavernous vessels stained for AM. Intense AM immunostaining was found in germinal cells and in peritubular myocytes and Leydig cells in the testis.

CONCLUSIONS

These findings demonstrated for the first time that AM is localized in human male reproductive system. The local secretion of AM suggests that AM may contribute either in the penile erection and in the regulation of testicular function and sperm motility.

Adrenomedullin: a new target for the design of small molecule modulators with promising pharmacological activities

Adrenomedullin (AM) is a 52-amino acid peptide with a pluripotential activity. AM is expressed in many tissues throughout the body, and plays a critical role in several diseases such as cancer, diabetes, cardiovascular and renal disorders, among others. While AM is a protective agent against cardiovascular disorders, it behaves as a stimulating factor in other pathologies such as cancer and diabetes. Therefore, AM is a new and promising target for the development of molecules which, through their ability to regulate AM levels, could be used in the treatment of these pathologies.

The adolescent varicocele: to treat or not to treat

Whether to treat adolescents with varicocele is controversial because over 80% of adult varicoceles are not associated with infertility. Most physicians agree that treating all adolescents with varicocele and subjecting boys to unnecessary surgery is inappropriate,costly, and not without ethical considerations. Waiting until patients present as adults with potentially irreversible infertility, however, is equally unacceptable. Pediatricians and urologists must determine which adolescents are at greatest risk for future fertility problems and warrant early intervention. This article reviews the current literature surrounding adolescent varicocele and offers recommendations for identifying individuals who would most benefit from treatment.

Cell and molecular biology of the multifunctional peptide, adrenomedullin

Adrenomedullin (AM) is a recently discovered regulatory peptide involved in many functions including vasodilatation, electrolyte balance, neurotransmission, growth, and hormone secretion regulation, among others. This 52-amino acid peptide is expressed by specific cell types in many organs throughout the body. A complex receptor system has been described for AM; it requires at least the presence of a seven-transmembrane-domain G-protein-coupled receptor, a single-transmembrane-domain receptor activity modifying protein, and a receptor component protein needed to establish the connection with the downstream signal transduction pathway, which usually involves cyclicAMP. In addition, a serum-binding protein regulates the biological actions of AM, frequently by increasing AM functional attributes. Changes in levels of circulating AM correlate with several critical diseases, including cardiovascular and renal disorders, sepsis, cancer, and diabetes. Whether AM is a causal agent, a protective reaction, or just a marker for these diseases is currently under investigation. New technologies seeking to elevate and/or reduce AM levels are being investigated as potential therapeutic avenues.

Varicocele: current concepts in pathophysiology, diagnosis, and treatment

Although significant advances have been made in the understanding of varicoceles, a clear pathophysiologic mechanism remains elusive. Most likely, a varicocele is the result of a multifactorial process. Appreciation of the complex venous drainage of the testis remains a key to maximizing the chances for treatment success. Likewise, the advent of microsurgical repair has minimized complications. Fortunately, times have improved since the early nineteenth century, when the French surgeon Delpech (1772-1832) was killed by a disgruntled patient on whom he had performed a varicocele repair.