Experimental Cryptorchidism Causes Chronic Inflammation and a Progressive Decline in Sertoli Cell and Leydig Cell Function in the Adult Rat Testis

Cryptorchidism causes spermatogenic failure and reduced serum androgen levels, as well as testicular oedema and fibrosis, which are hallmarks of inflammation. However, the role of inflammation and the effects of cryptorchidism on Sertoli cell and Leydig cell function at the molecular level remain ill-defined. Bilateral cryptorchidism was surgically induced in adult rats for 7 and 14 weeks. Testis weights decreased to 40% of normal within 7 weeks, due to loss of all developing spermatogenic cells except spermatogonia, but did not decrease further at 14 weeks. Serum FSH and LH were increased at both time points, consistent with a loss of feedback by inhibin and testosterone. This damage was accompanied by progressive accumulation of interstitial fluid and peritubular fibrosis, and a progressive decline of several critical Sertoli cell genes (Sox9, Inha (inhbin α-subunit), Cldn11 (claudin 11), Gja1 (connexin 43), and Il1a (interleukin-1α)) and the Leydig cell steroidogenic enzymes, Cyp11a1, Hsd3b1, and Hs17b3. Activin B and the activin-binding protein, follistatin, also declined, but the intratesticular concentration of activin A, which is a regulator of inflammatory responses, was largely unaffected at either time point. Expression of genes involved in inflammation (Tnf, Il10, Il1b, Mcp1) and fibrosis (Acta2, Col1a1) were considerably elevated at both time points. These data indicate that induction of experimental cryptorchidism, which causes complete failure of spermatogenesis in the adult rat, also induces chronic testicular inflammation, manifesting in oedema and fibrosis, and a progressive decline of Sertoli and Leydig cell gene expression and function.

Acute heat-treatment disrupts inhibin-related protein production and gene expression in the adult rat testis

Heat reversibly disrupts spermatogenesis, but the effects on Sertoli cell (SC) function and inhibin/activin-related proteins are less well-defined. Adult rat testis weights decreased by 40% within 2 weeks after heat-treatment (43 °C, 15 min), due to loss of pachytene spermatocytes and round spermatids. Coincident effects were reduced SC nuclear volume at one week and >50% reduction in expression of several critical SC genes (Inha, Cld11, Gja1, Tjp1, Cldn3) by 2 weeks. Leydig cell steroidogenic enzymes, Cyp11a1, Hsd3b1, were also reduced. Activin gene expression was unaffected at this time, but expression of the activin-binding protein, follistatin (Fst), increased >2-fold. At 4-8 weeks, coincident with the recovery of spermatocytes and early spermatids, but progressive loss of elongated spermatids, most SC genes had recovered; however, testicular activin A was reduced and activin B increased. At 8 weeks, serum inhibin was decreased and, consequently, serum FSH increased. Crucially, germ cell damage was not associated with a significant inflammatory response. At 14 weeks, most testicular parameters had returned to normal, but testis weights remained slightly reduced. These data indicate that, following acute heat-treatment, expression of several key Sertoli and Leydig cell genes declined in parallel with the initial loss of meiotic germ cells, whereas activins were responsive to the subsequent loss of mature spermatids, leading to an increase in testicular activin B production relative to activin A.

Inhibition of activin signaling in lung adenocarcinoma increases the therapeutic index of platinum chemotherapy

Resistance to platinum chemotherapy is a long-standing problem in the management of lung adenocarcinoma. Using a whole-genome synthetic lethal RNA interference screen, we identified activin signaling as a critical mediator of innate platinum resistance. The transforming growth factor-β (TGFβ) superfamily ligands activin A and growth differentiation factor 11 (GDF11) mediated resistance via their cognate receptors through TGFβ-activated kinase 1 (TAK1), rather than through the SMAD family of transcription factors. Inhibition of activin receptor signaling or blockade of activin A and GDF11 by the endogenous protein follistatin overcame this resistance. Consistent with the role of activin signaling in acute renal injury, both therapeutic interventions attenuated acute cisplatin-induced nephrotoxicity, its major dose-limiting side effect. This cancer-specific enhancement of platinum-induced cell death has the potential to dramatically improve the safety and efficacy of chemotherapy in lung cancer patients.

Activin over-expression in the testis of mice lacking the inhibin α-subunit gene is associated with androgen deficiency and regression of the male reproductive tract

Regionalised interaction of the activins, follistatin and inhibin was investigated in the male reproductive tract of mice lacking the inhibin α-subunit (Inha^-/-). Serum and intratesticular activin B, although not activin A and follistatin, were increased in Inha^-/- mice at 25 days of age, but all three proteins were elevated at 56 days. None of these proteins were altered within the epididymis and vas deferens at either age. At 25 days, histology of the epididymis and vas deferens was similar to wild-type. At 56 days, the testis contained extensive somatic cell tumours, leading to Leydig cell regression and testosterone deficiency. The epididymis and vas deferens showed epithelial regression and increased prominence of the interstitial stroma. Immunoregulatory and fibrotic gene expression in the epididymis and vas deferens were unchanged. Thus, absence of the inhibin α-subunit has marginal effects on activins in the epididymis and vas deferens, and regression of these tissues is associated with androgen deficiency.

Weighting of orthostatic intolerance time measurements with standing difficulty score stratifies ME/CFS symptom severity and analyte detection

BACKGROUND

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is clinically defined and characterised by persistent disabling tiredness and exertional malaise, leading to functional impairment.

METHODS

This study introduces the weighted standing time (WST) as a proxy for ME/CFS severity, and investigates its behaviour in an Australian cohort. WST was calculated from standing time and subjective standing difficulty data, collected via orthostatic intolerance assessments. The distribution of WST for healthy controls and ME/CFS patients was correlated with the clinical criteria, as well as pathology and cytokine markers. Included in the WST cytokine analyses were activins A and B, cytokines causally linked to inflammation, and previously demonstrated to separate ME/CFS from healthy controls. Forty-five ME/CFS patients were recruited from the CFS Discovery Clinic (Victoria) between 2011 and 2013. Seventeen healthy controls were recruited concurrently and identically assessed.

RESULTS

WST distribution was significantly different between ME/CFS participants and controls, with six diagnostic criteria, five analytes and one cytokine also significantly different when comparing severity via WST. On direct comparison of ME/CFS to study controls, only serum activin B was significantly elevated, with no significant variation observed for a broad range of serum and urine markers, or other serum cytokines.

CONCLUSIONS

The enhanced understanding of standing test behaviour to reflect orthostatic intolerance as a ME/CFS symptom, and the subsequent calculation of WST, will encourage the greater implementation of this simple test as a measure of ME/CFS diagnosis, and symptom severity, to the benefit of improved diagnosis and guidance for potential treatments.

Comparative analysis of activins A and B in the adult mouse epididymis and vas deferens

Activin A regulates testicular and epididymal development, but the role of activin B in the epididymis and vas deferens is unknown. Mouse models with reduced activin A (Inhba+/− and InhbaBK/+), or its complete absence (InhbaBK/BK), were investigated to identify specific roles of activins in the male reproductive tract. In 8-week-old Inhba+/− mice, serum activin A decreased by 70%, with a 50% reduction of gene expression and protein in the testis, epididymis and vas deferens. Activin B and the activin-binding protein, follistatin, were similar to wild-type. Testis weights were slightly reduced in Inhba+/− mice, but the epididymis and vas deferens were normal, while the mice were fertile. Activin A was decreased by 70% in the serum, testis, epididymis and vas deferens of InhbaBK/+ mice and was undetectable in InhbaBK/BK mice, but activin B and follistatin levels were similar to wild-type. In 6-week-old InhbaBK/BK mice, testis weights were 60% lower and epididymal weights were 50% lower than in either InhbaBK/+ or wild-type mice. The cauda epididymal epithelium showed infoldings and less intra-luminal sperm, similar to 3.5-week-old wild-type mice, but at 8 weeks, no structural differences in the testis or epididymis were noted between InhbaBK/BK and wild-type mice. Thus, Inhbb can compensate for Inhba in regulating epididymal morphology, although testis and epididymal maturation is delayed in mice lacking Inhba. Crucially, reduction or absence of activin A, at least in the presence of normal activin B levels, does not lead to major defects in the adult epididymis or vas deferens.

Induction of experimental autoimmune orchitis in mice: responses to elevated circulating levels of the activin-binding protein, follistatin

Experimental autoimmune orchitis (EAO) is a rodent model of chronic testicular inflammation that mimics the pathology observed in some types of human infertility. In a previous study, testicular expression of the inflammatory/immunoregulatory cytokine, activin A, was elevated in adult mice during the onset of EAO, indicating a potential role in the regulation of the disease. Consequently, we examined the development of EAO in mice with elevated levels of follistatin, an endogenous activin antagonist, as a potential therapeutic approach to testicular inflammation. Prior to EAO induction, mice received a single intramuscular injection of a non-replicative recombinant adeno-associated viral vector carrying a gene cassette of the circulating form of follistatin, FST315 (FST group). Serum follistatin levels were increased 5-fold in the FST group compared with the control empty vector (EV) group at 30 and 50 days of EAO, but intra-testicular levels of follistatin or activin A were not significantly altered. Induction of EAO was reduced, but not prevented, with mild-to-severe damage in 75% of the EV group and 40% of the FST group, at 50 days following immunisation with testicular homogenate. However, the EAO damage score (based on disruption of the blood-testis barrier, apoptosis, testicular damage and fibrosis) and extent of intratesticular inflammation (expression of inflammatory mediators) were directly proportional to the levels of activin A measured in the testis at 50 days. These data implicate activin A in the progression of EAO, thereby providing a potential therapeutic target; however, elevating circulating follistatin levels were not sufficient to prevent EAO development.

Hyperglycemia is associated with reduced testicular function and activin dysregulation in the Ins2Akita+/- mouse model of type 1 diabetes

Type 1 diabetes (T1D) is associated with subfertility in men. We hypothesised that this results from inhibitory effects of chronic hyperglycemia on testicular function and used the Ins2^Akita+/- mouse model to investigate this. Diabetic mice exhibited progressive testicular dysfunction, with a 30% reduction in testis weight at 24 weeks of age. Diabetic mice showed significantly reduced seminiferous tubule diameters and increased spermatogenic disruption, although testes morphology appeared grossly normal. Unexpectedly, serum LH and intra-testicular testosterone were similar in all groups. Ins2^Akita+/- mice displayed elevation of the testicular inflammatory cytokines activin A and IL-6. Intratesticular activin B was downregulated, while the activin regulatory proteins, follistatin and inhibin, were unchanged. Activin signalling, measured by pSmad3 and Smad4 production, was enhanced in diabetic mice only. These results suggest that prolonged exposure to hyperglycemia in the Ins2^Akita+/- mice leads to progressive testicular disruption mediated by testicular activin activity, rather than hormonal dysregulation.

Follistatin attenuates radiation-induced fibrosis in a murine model

Purpose

Fibrosis can be a disabling, severe side effect of radiotherapy that can occur in patients, and for which there is currently no effective treatment. The activins, proteins which are members of the TGFβ superfamily, have a major role in stimulating the inflammatory response and subsequent fibrosis. Follistatin is an endogenous protein that binds the activins virtually irreversibly and inhibits their actions. These studies test if follistatin can attenuate the fibrotic response using a murine model of radiation-induced fibrosis.

Experimental design

C57BL/6 mice were subcutaneously injected with follistatin 24 hours prior to irradiation. Mice were irradiated in a 10 x 10 mm square area of the right hind leg with 35 Gy and were given follistatin 24 hours before radiation and three times a week for six months following. Leg extension was measured, and tissue was collected for histological and molecular analysis to evaluate the progression of the radiation-induced fibrosis.

Results

Leg extension was improved in follistatin treated mice compared to vehicle treated mice at six months after irradiation. Also, epidermal thickness and cell nucleus area of keratinocytes were decreased by the follistatin treatment compared to the cells in irradiated skin of control mice. Finally, the gene expression of transforming growth factor β1 (Tgfb1), and smooth muscle actin (Acta2) were decreased in the irradiated skin and Acta2 and inhibin βA subunit (Inhba) were decreased in the irradiated muscle of the follistatin treated mice.

Conclusions

Follistatin attenuated the radiation-induced fibrotic response in irradiated mice. These studies provide the data to support further investigation of the use of follistatin to reduce radiation-induced fibrosis in patients undergoing radiotherapy for cancer.

Activin B is a novel biomarker for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) diagnosis: a cross sectional study

Background

Investigations of activin family proteins as serum biomarkers for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). CFS/ME is a disease with complex, wide-ranging symptoms, featuring persistent fatigue of 6 months or longer, particularly post exertion. No definitive biomarkers are available.

Methods

A cross-sectional, observational study of CFS/ME patients fulfilling the 2003 Canadian Consensus Criteria, in parallel with healthy non-fatigued controls, was conducted. Comparisons with a previously defined activin reference population were also performed. For the total study cohort the age range was 18–65 years with a female: male participant ratio of greater than 3:1. All participants were assessed via a primary care community clinic. Blood samples were collected for pathology testing after physical examination and orthostatic intolerance assessment. Cytokines, activin A, activin B and follistatin were also measured in sera from these samples. All data were compared between the CFS/ME and control cohorts, with the activins and follistatin also compared with previously defined reference intervals.

Results

Serum activin B levels for CFS/ME participants were significantly elevated when compared to the study controls, as well as the established reference interval. Serum activin A and follistatin were within their normal ranges. All routine and special pathology markers were within the normal laboratory reference intervals for the total study cohort, with no significant differences detected between CFS/ME and control groups. Also, no significant differences were detected for IL-2, IL-4, IL-6, IL-10, IL-17A, TNF or IFN-gamma.

Conclusion

Elevated activin B levels together with normal activin A levels identified patients with the diagnostic symptoms of CFS/ME, thus providing a novel serum based test. The activins have multiple physiological roles and capture the diverse array of symptoms experienced by CFS/ME patients.

Substantial Increases Occur in Serum Activins and Follistatin during Lung Transplantation

Background

Lung transplantation exposes the donated lung to a period of anoxia. Re-establishing the circulation after ischemia stimulates inflammation causing organ damage. Since our published data established that activin A is a key pro-inflammatory cytokine, we assessed the roles of activin A and B, and their binding protein, follistatin, in patients undergoing lung transplantation.

Methods

Sera from 46 patients participating in a published study of remote ischemia conditioning in lung transplantation were used. Serum activin A and B, follistatin and 11 other cytokines were measured in samples taken immediately after anaesthesia induction, after remote ischemia conditioning or sham treatment undertaken just prior to allograft reperfusion and during the subsequent 24 hours.

Results

Substantial increases in serum activin A, B and follistatin occurred after the baseline sample, taken before anaesthesia induction and peaked immediately after the remote ischemia conditioning/sham treatment. The levels remained elevated 15 minutes after lung transplantation declining thereafter reaching baseline 2 hours post-transplant. Activin B and follistatin concentrations were lower in patients receiving remote ischemia conditioning compared to sham treated patients but the magnitude of the decrease did not correlate with early transplant outcomes.

Conclusions

We propose that the increases in the serum activin A, B and follistatin result from a combination of factors; the acute phase response, the reperfusion response and the use of heparin-based anti-coagulants.

LRGUK-1 is required for basal body and manchette function during spermatogenesis and male fertility

Male infertility affects at least 5% of reproductive age males. The most common pathology is a complex presentation of decreased sperm output and abnormal sperm shape and motility referred to as oligoasthenoteratospermia (OAT). For the majority of OAT men a precise diagnosis cannot be provided. Here we demonstrate that leucine-rich repeats and guanylate kinase-domain containing isoform 1 (LRGUK-1) is required for multiple aspects of sperm assembly, including acrosome attachment, sperm head shaping and the initiation of the axoneme growth to form the core of the sperm tail. Specifically, LRGUK-1 is required for basal body attachment to the plasma membrane, the appropriate formation of the sub-distal appendages, the extension of axoneme microtubules and for microtubule movement and organisation within the manchette. Manchette dysfunction leads to abnormal sperm head shaping. Several of these functions may be achieved in association with the LRGUK-1 binding partner HOOK2. Collectively, these data establish LRGUK-1 as a major determinant of microtubule structure within the male germ line.

The activin A antagonist follistatin inhibits cystic fibrosis-like lung inflammation and pathology

Cystic fibrosis (CF) is the most common life-limiting genetically acquired respiratory disorder. Patients with CF have thick mucus obstructing the airways leading to recurrent infections, bronchiectasis and neutrophilic airway inflammation culminating in deteriorating lung function. Current management targets airway infection and mucus clearance, but despite recent advances in care, life expectancy is still only 40 years. We investigated whether activin A is elevated in CF lung disease and whether inhibiting activin A with its natural antagonist follistatin retards lung disease progression. We measured serum activin A levels, lung function and nutritional status in CF patients. We studied the effect of activin A on CF lung pathogenesis by treating newborn CF transgenic mice (β-ENaC) intranasally with the natural activin A antagonist follistatin. Activin A levels were elevated in the serum of adult CF patients, and correlated inversely with lung function and body mass index. Follistatin treatment of newborn β-ENaC mice, noted for respiratory pathology mimicking human CF, decreased the airway activin A levels and key features of CF lung disease including mucus hypersecretion, airway neutrophilia and levels of mediators that regulate inflammation and chemotaxis. Follistatin treatment also increased body weight and survival of β-ENaC mice, with no evidence of local or systemic toxicity. Our findings demonstrate that activin A levels are elevated in CF and provide proof-of-concept for the use of the activin A antagonist, follistatin, as a therapeutic in the long-term management of lung disease in CF patients.

Serum activin A and B, and follistatin in critically ill patients with influenza A(H1N1) infection

Background

Activin A and its binding protein follistatin (FS) are increased in inflammatory disorders and sepsis. Overexpression of activin A in the lung causes similar histopathological changes as acute respiratory distress syndrome (ARDS). ARDS and severe respiratory failure are complications of influenza A(H1N1) infection. Interleukin 6 (IL-6), which in experimental studies increases after activin A release, is known to be related to the severity of H1N1 infection. Our aim was to evaluate the levels of activin A, activin B, FS, IL-6 and IL-10 and their association with the severity of respiratory failure in critically ill H1N1 patients.

Methods

A substudy of a prospective, observational cohort of H1N1 patients in Finnish intensive care units (ICU). Clinical information was recorded during ICU treatment, and serum activin A, activin B, FS, IL-6 and IL-10 were measured at admission to ICU and on days 2 and 7.

Results

Blood samples from 29 patients were analysed. At the time of admission to intensive care unit, elevated serum levels above the normal range for respective age group and sex were observed in 44% for activin A, 57% for activin B, and 39% for FS. In 13 of the 29 patients, serial samples at all time points were available and in these the highest activin A, activin B and FS were above the normal range in 85%, 100% and 46% of the patients, respectively. No difference in baseline or highest activin A or activin B was found in patients with or without acute lung injury (ALI) or ARDS (P > 0.05 for all). Peak levels of IL-6 were significantly elevated in ALI/ARDS patients. Peak activin A and activin A/FS were associated with ventilatory support free-days, severity of acute illness and length of ICU stay (P < 0.05 for all).

Conclusions

Higher than normal values of these proteins were common in patients with H1N1 infection but we found no association with the severity of their respiratory failure.

Follistatin is induced by ionizing radiation and potentially predictive of radiosensitivity in radiation-induced fibrosis patient derived fibroblasts

Follistatin is a potent regulator of the inflammatory response and binds to and inhibits activin A action. Activin A is a member of the TGFβ protein superfamily which has regulatory roles in the inflammatory response and in the fibrotic process. Fibrosis can occur following cell injury and cell death induced by agents such as ionizing radiation (IR). IR is used to treat cancer and marked fibrotic response is a normal tissue (non-tumour) consequence in a fraction of patients under the current dose regimes. The discovery and development of a therapeutic to abate fibrosis in these radiosensitive patients would be a major advance for cancer radiotherapy. Likewise, prediction of which patients are susceptible to fibrosis would enable individualization of treatment and provide an opportunity for pre-emptive fibrosis control and better tumour treatment outcomes. The levels of activin A and follistatin were measured in fibroblasts derived from patients who developed severe radiation-induced fibrosis following radiotherapy and compared to fibroblasts from patients who did not. Both follistatin and activin A gene expression levels were increased following IR and the follistatin gene expression level was lower in the fibroblasts from fibrosis patients compared to controls at both basal levels and after IR. The major follistatin transcript variants were found to have a similar response to IR and both were reduced in fibrosis patients. Levels of follistatin and activin A secreted in the fibroblast culture medium also increased in response to IR and the relative follistatin protein levels were significantly lower in the samples derived from fibrosis patients. The decrease in the follistatin levels can lead to an increased bioactivity of activin A and hence may provide a useful measurement to identify patients at risk of a severe fibrotic response to IR. Additionally, follistatin, by its ability to neutralise the actions of activin A may be of value as an anti-fibrotic for radiation induced fibrosis.

Loss of the nuclear receptor corepressor SLIRP compromises male fertility

Nuclear receptors (NRs) and their coregulators play fundamental roles in initiating and directing gene expression influencing mammalian reproduction, development and metabolism. SRA stem Loop Interacting RNA-binding Protein (SLIRP) is a Steroid receptor RNA Activator (SRA) RNA-binding protein that is a potent repressor of NR activity. SLIRP is present in complexes associated with NR target genes in the nucleus; however, it is also abundant in mitochondria where it affects mitochondrial mRNA transcription and energy turnover. In further characterisation studies, we observed SLIRP protein in the testis where its localization pattern changes from mitochondrial in diploid cells to peri-acrosomal and the tail in mature sperm. To investigate the in vivo effects of SLIRP, we generated a SLIRP knockout (KO) mouse. This animal is viable, but sub-fertile. Specifically, when homozygous KO males are crossed with wild type (WT) females the resultant average litter size is reduced by approximately one third compared with those produced by WT males and females. Further, SLIRP KO mice produced significantly fewer progressively motile sperm than WT animals. Electron microscopy identified disruption of the mid-piece/annulus junction in homozygous KO sperm and altered mitochondrial morphology. In sum, our data implicates SLIRP in regulating male fertility, wherein its loss results in asthenozoospermia associated with compromised sperm structure and mitochondrial morphology.

Male reproductive health disorders among Aboriginal and Torres Strait Islander men: a hidden problem?

OBJECTIVE

To better understand help-seeking behaviours and reproductive health disorders among Aboriginal and Torres Strait Islander men.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional mixed-methods study conducted from 1 May 2004 to 30 April 2005 of 293 Aboriginal and Torres Strait Islander men aged 18 years and over from urban, rural and remote communities in the Northern Territory and Queensland.

MAIN OUTCOME MEASURES

Subscale of the International Index of Erectile Function, self-reported help-seeking behaviours for erectile dysfunction (ED) and prostate disease, thematic analysis of semi-structured interviews and focus groups.

RESULTS

The prevalence of moderate-to-severe ED increased across age groups, from about 10% in younger men (under 35 years) to 28% in men aged 55-74 years. Moderate-to-severe ED was strongly associated with reporting a chronic condition (odds ratio [OR], 3.67) and residing in a remote area (OR, 2.94). Aboriginal and Torres Strait Islander men aged 40-59 years showed similar low levels of help-seeking behaviours compared with non-Indigenous men from a comparable population-based study. About half of the men with ED saw a doctor or received treatment for ED in each population. While prostate cancer rates were low in both studies, testing for prostate problems was less frequent in Aboriginal and Torres Strait Islander men (11.4%) than in non-Indigenous men (34.1%, P < 0.001), despite similar levels of concern about prostate cancer. Barriers to help-seeking included shame, culturally inappropriate services and lack of awareness.

CONCLUSION

This study, the first to investigate reproductive health of Aboriginal and Torres Strait Islander men, found low levels of help-seeking behaviours for reproductive health disorders, with implications for missing a predictor of chronic disease and late diagnosis of prostate disease.

Expression patterns of activin, inhibin and follistatin variants in the adult male mouse reproductive tract suggest important roles in the epididymis and vas deferens

Activin A and its inhibitors follistatin and inhibin play key roles in development and function of the male reproductive tract. Quantitative (q) polymerase chain reaction (PCR) was used to evaluate the expression of Inhba (the gene encoding activin A subunits), Inha and Inhbb (genes encoding the inhibin B subunits), as well as the genes for follistatin (Fst) and follistatin-like 3 (Fstl3) and the activin receptor subunits, in the male mouse reproductive tract. A qPCR assay that discriminated between the two follistatin variants of Fst288 (tissue-bound form) and Fst315 (circulating) was established. Activin A protein was measured by ELISA, whereas the inhibin α-subunit and total follistatin proteins were measured by radioimmunoassay (RIA). A screen of 22 tissues demonstrated tissue-specific regulation of the follistatin variants, with Fst288 highly expressed in the vas deferens and Fst315 most highly expressed in the skin. The expression of Fst288 and Fst315 and follistatin protein levels increased progressively from the testis through to the distal vas deferens. Inhba and the activin receptors were highly expressed in the epididymis, but activin A protein was elevated in both the epididymis and vas deferens. Inhibin α-subunit mRNA and protein and Inhbb expression were highest in the testis. These results indicate a role for activin A within the epididymis, but also that activin A bioactivity may be increasingly inhibited by follistatin distally along the male reproductive tract.

The roles of activin A and its binding protein, follistatin, in inflammation and tissue repair

Activin A, a member of the transforming growth factor-β superfamily of cytokines, is a critical controller of inflammation, immunity and fibrosis. It is rapidly released into the blood following a lipopolysaccharide challenge in experimental animals, through activation of the Toll-like receptor 4 signalling pathway. Blocking activin action by pre-treatment with its binding protein, follistatin, modifies the inflammatory cytokine cascade, and reduces the severity of the subsequent inflammatory response and mortality. Likewise, high serum levels of activin A are predictive of death in patients with septicaemia. However, activin A has complex immunomodulatory actions. It is produced by inflammatory macrophages, but can regulate either pro- or anti-inflammatory responses in these cells, depending on their prior activation status. Activin A is also produced by Th2 cells, and stimulates antibody production by B cells and the development of regulatory T cells. Production of activin A during inflammatory responses stimulates fibrosis and tissue remodelling, and follistatin inhibits these actions of activin A. The modulation of activin by follistatin may represent an important therapeutic target for the modulation and amelioration of inflammatory and fibrotic disorders.

The regulation and functions of activin and follistatin in inflammation and immunity

The activins are members of the transforming growth factor β superfamily with broad and complex effects on cell growth and differentiation. Activin A has long been known to be a critical regulator of inflammation and immunity, and similar roles are now emerging for activin B, with which it shares 65% sequence homology. These molecules and their binding protein, follistatin, are widely expressed, and their production is increased in many acute and chronic inflammatory conditions. Synthesis and release of the activins are stimulated by inflammatory cytokines, Toll-like receptor ligands, and oxidative stress. The activins interact with heterodimeric serine/threonine kinase receptor complexes to activate SMAD transcription factors and the MAP kinase signaling pathways, which mediate inflammation, stress, and immunity. Follistatin binds to the activins with high affinity, thereby obstructing the activin receptor binding site, and targets them to cell surface proteoglycans and lysosomal degradation. Studies on transgenic mice and those with gene knockouts, together with blocking studies using exogenous follistatin, have established that activin A plays critical roles in the onset of cachexia, acute and chronic inflammatory responses such as septicemia, colitis and asthma, and fibrosis. However, activin A also directs the development of monocyte/macrophages, myeloid dendritic cells, and T cell subsets to promote type 2 and regulatory immune responses. The ability of both endogenous and exogenous follistatin to block the proinflammatory and profibrotic actions of activin A has led to interest in this binding protein as a potential therapeutic for limiting the severity of disease and to improve subsequent damage associated with inflammation and fibrosis. However, the ability of activin A to sculpt the subsequent immune response as well means that the full range of effects that might arise from blocking activin bioactivity will need to be considered in any therapeutic applications.

Determinants of male reproductive health disorders: the Men in Australia Telephone Survey (MATeS)

BACKGROUND

The relationship between reproductive health disorders and lifestyle factors in middle-aged and older men is not clear. The aim of this study is to describe lifestyle and biomedical associations as possible causes of erectile dysfunction (ED), prostate disease (PD), lower urinary tract symptoms (LUTS) and perceived symptoms of androgen deficiency (pAD) in a representative population of middle-aged and older men, using the Men in Australia Telephone Survey (MATeS).

METHODS

A representative sample (n = 5990) of men aged 40+ years, stratified by age and State, was contacted by random selection of households, with an individual response rate of 78%. All men participated in a 20-minute computer-assisted telephone interview exploring general and reproductive health. Associations between male reproductive health disorders and lifestyle and biomedical factors were analysed using multivariate logistic regression (odds ratio [95% confidence interval]). Variables studied included age, body mass index, waist circumference, smoking, alcohol consumption, physical activity, co-morbid disease and medication use for hypertension, high cholesterol and symptoms of depression.

RESULTS

Controlling for age and a range of lifestyle and co-morbid exposures, sedentary lifestyle and being underweight was associated with an increased likelihood of ED (1.4 [1.1-1.8]; 2.9 [1.5-5.8], respectively) and pAD (1.3 [1.1-1.7]; 2.7 [1.4-5.0], respectively. Diabetes and cardiovascular disease were both associated with ED, with hypertension strongly associated with LUTS and pAD. Current smoking (inverse association) and depressive symptomatology were the only variables independently associated with PD. All reproductive disorders showed consistent associations with depression (measured either by depressive symptomatology or medication use) in both age-adjusted and multivariate analyses.

CONCLUSION

A range of lifestyle factors, more often associated with chronic disease, were significantly associated with male reproductive health disorders. Education strategies directed to improving general health may also confer benefits to male reproductive health.

A new 'total' activin B enzyme-linked immunosorbent assay (ELISA): development and validation for human samples

BACKGROUND AND OBJECTIVE

There are currently no sensitive and specific assays for activin B that could be utilized to study human biological fluids. The aim of this project was to develop and validate a 'total' activin B ELISA for use with human biological fluids and establish concentrations of activin B in the circulation and fluids from the reproductive organs.

DESIGN

The new ELISA was validated and then used to measure activin B levels in the circulation of healthy participants, IVF patients, pregnant women and in ovarian follicular fluid and seminal plasma.

PATIENTS AND MEASUREMENTS

Healthy adult subjects (n = 143), subjects from an IVF clinic (n = 27) and pregnancy groups (n = 29) were sampled.

RESULTS

The sensitivity of the assay was 0.019 ng/ml. Validation of the activin B ELISA showed good recovery (90.7 +/- 9.8%) and linearity in biological fluid and cell culture media and low cross-reactivity with related analytes (inhibin B = 0.077% and activin A = 0.0034%). There was a negative correlation between activin B concentration (r = -0.281, P < 0.011) and females with increasing age. Patients attending IVF clinics had significantly lower levels of activin B compared with gender-matched control subjects. Ovarian follicular fluid and seminal plasma had 50-80 fold higher levels of activin B (mean = 5.35 and 3.66 ng/ml respectively) than sera (mean = 0.071 ng/ml).

CONCLUSIONS

This fully validated ELISA for activin B offers a tremendous utility for measuring this protein in a variety of normal physiological processes and in various clinical pathologies.

Activin and related proteins in inflammation: not just interested bystanders

Activin A, a member of the transforming growth factor-beta superfamily, is released rapidly into the circulation during inflammation. This review examines the evidence that activin is a critical mediator of inflammation and immunity. Activin modulates several aspects of the inflammatory response, including release of pro-inflammatory cytokines, nitric oxide production and immune cell activity. Crucially, inhibiting activin with follistatin, a high affinity binding protein, alters the pattern of cytokines released and improves survival in a mouse model of endotoxic shock. Serum and tissue concentrations of activin are elevated in a wide range of pathological conditions. The utility of activin as a diagnostic marker of clinical inflammation and the use of follistatin to block activin actions therapeutically are also discussed.

Inhibin, activin, follistatin and FSH serum levels and testicular production are highly modulated during the first spermatogenic wave in mice

Testicular development is governed by the combined influence of hormones and proteins, including FSH, inhibins, activins and follistatin (FST). This study documents the expression of these proteins and their corresponding mRNAs, in testes and serum from mice aged 0 through 91 dayspost partum(dpp), using real-time PCR,in situhybridisation, immunohistochemistry, ELISA and RIA. Serum immunoactive total inhibin and FSH levels were negatively correlated during development, with FSH levels rising and inhibin levels falling. Activin A production changed significantly during development, with subunit mRNA and protein levels declining rapidly after 4 dpp, while simultaneously levels of the activin antagonists, FST and inhibin/activin βC, increased. Inhibin/activin βAand βBsubunit mRNAs were detected in Sertoli, germ and Leydig cells throughout testis development, with the βAsubunit also detected in peritubular myoid cells. The α, βA, βBand βCsubunit proteins were detected in Sertoli and Leydig cells of developing and adult mouse testes. While βAand βBsubunit proteins were observed in spermatogonia and spermatocytes in immature testes, βCwas localised to leptotene and zygotene spermatocytes in immature and adult testes. Nuclear βAsubunit protein was observed in primary spermatocytes and nuclear βCsubunit in gonocytes and round spermatids. The changing spatial and temporal distributions of inhibins and activins indicate that their modulated synthesis and action are important during onset of murine spermatogenesis. This study provides a foundation for evaluation of these proteins in mice with disturbed testicular development, enabling their role in normal and perturbed spermatogenesis to be more fully understood.

Molecular identification of lyso-glycerophosphocholines as endogenous immunosuppressives in bovine and rat gonadal fluids

The ability of the gametes to escape detection by the immune system is vital to successful human reproduction. Furthermore, the observed capacity of the testis in some species to support tissue grafts without rejection (immunological privilege) indicates that spermatogenic cells are protected by local immunoregulatory mechanisms. One of these mechanisms involves targeting T cells for inactivation and destruction within the testicular environment. Although the fluids of the testis and ovary surrounding the developing gametes contain soluble factors that inhibit T cells, the identity of the molecule(s) responsible for this activity has been unknown. Using a specific T-cell proliferation assay to monitor bioactivity, these molecules were purified from bovine ovarian follicular fluid by methanol extraction and sequential reverse-phase HPLC (RP-HPLC). All purified active fractions coincided with the elution position on RP-HPLC of several small molecules ranging in size from 496 to 522 Da. The same molecules were localized to the immunosuppressive fractions of rat testicular interstitial fluid. The active molecules were identified, using capillary electrophoresis electrospray ionization mass spectroscopy, as lyso-glycerophosphocholines (lyso-GPCs), namely, 1-palmitoyl-sn-glycero-3-phosphocholine, 1-oleoyl-sn-glycero-3-phosphocholine, a 18:2a/lyso-GPC (putatively, 1-linoleoyl-sn-glycero-3-phosphocholine), and a 20:4a/lyso-GPC (putatively, 1-arachidonyl-sn-glycero-3-phosphocholine). Comparison of the bioactivity and mass spectroscopy profiles of two of the purified molecules with their synthetic standards confirmed the identification. These molecules inhibit T-cell proliferation in response to activation and induce apoptosis of these cells in a time- and dose-dependent manner. The emergence of gonadal lyso-GPCs as potential regulators of critical immune events opens up new avenues of inquiry into the origins of autoimmune infertility and more generally into mechanisms of peripheral immunoregulation and the development of novel immunosuppressives.

Sox8 is a critical regulator of adult Sertoli cell function and male fertility

Sox8 encodes a high-mobility group transcription factor that is widely expressed during development. Sox8, -9 and -10 form group E of the Sox gene family which has been implicated in several human developmental disorders. In contrast to other SoxE genes, the role of Sox8 is unclear and Sox8 mouse mutants reportedly showed only idiopathic weight loss and reduced bone density. The careful analysis of our Sox8 null mice, however, revealed a progressive male infertility phenotype. Sox8 null males only sporadically produced litters of reduced size at young ages. We have shown that SOX8 protein is a product of adult Sertoli cells and its elimination results in an age-dependent deregulation of spermatogenesis, characterized by sloughing of spermatocytes and round spermatids, spermiation failure and a progressive disorganization of the spermatogenic cycle, which resulted in the inappropriate placement and juxtaposition of germ cell types within the epithelium. Those sperm that did enter the epididymides displayed abnormal motility. These data show that SOX8 is a critical regulator of adult Sertoli cell function and is required for both its cytoarchitectural and paracrine interactions with germ cells.

Temporal expression of activin in acute burn wounds—From inflammatory cells to fibroblasts

Activin A is a member of the transforming growth factor-beta (TGF-beta) family of cytokines and growth factors and upregulation of this protein has been linked with a number of disease processes associated with chronic inflammation and fibrosis. Its potential involvement in burns has not yet been investigated. We therefore studied the localization of activin in tissue sections from excised mid- and deep dermal and full thickness cutaneous burn by immunohistochemistry. There was cell-specific temporal expression in tissues with prominent expression from day 4 onwards in lymphocytes and histiocytes and expression from day 8 onwards in reactive fibroblasts and endothelial cells. Immunopositivity over the first 18 days persisted in reactive fibroblasts and lymphocytes although the latter were in most circumstances decreasing in number. These data are consistent with activin A being central to the inflammatory and repair phases occurring in burnt skin and early scar formation. Modulation of activin expression and actions may, therefore, be a target for the management of burns.

Evidence that androgens regulate early developmental events, prior to sexual differentiation

Androgen signaling is critical for normal fetal development but is not thought to regulate events in early embryogenesis. Given the interest in factors controlling the differentiation of embryonic stem (ES) cells, we have explored the possibility that androgens may play a role. This study demonstrates expression of androgen receptor (AR) RNA and protein in four independent mouse ES (mES) cell lines, and shows that the AR is functional and can interact with transfected androgen response elements to promote green fluorescent protein expression. AR mRNA was detected throughout 10-d differentiation in embryoid bodies (EBs). Exposure of EBs to testosterone (T) or dihydrotestosterone, at doses of 1 and 0.1 mum, respectively, promoted formation of beating cardiomyocytes. Flow cytometric analyses demonstrated a significant increase in the number of alpha-actinin and tropomyosin (cardiac markers) positive cells after these treatments. Addition of flutamide (1 microM) to T-treated EBs inhibited the T-induced proliferation of cardiomyocytes, confirming that, in this instance, androgens act via the classical AR-mediated genomic pathway. We also report that mES cells express key steroidogenic enzymes, as detected by RT-PCR, and during 24-h incubations secrete T at concentrations of 1.38 +/- 0.22 nM, levels comparable to those secreted by cultured Leydig cells. These novel data demonstrate the capacity of androgens to stimulate increased differentiation of mouse ES cells to cardiomyocytes, and are in keeping with recent observations that AR-deficient mice exhibit cardiac impairment in adulthood.

Female infertility and disrupted angiogenesis are actions of specific follistatin isoforms

The circulating and tissue-bound forms of follistatin (FST315 and FST288, respectively) modulate the actions of activins. FST knockout (KO/null) mice, lacking both isoforms, die perinatally with defects in lung, skin, and the musculoskeletal system. Using constructs of the human FST gene engineered to enable expression of each isoform under the control of natural regulatory elements, transgenic mouse lines were created and crossed with FST null mice to attempt to rescue the neonatal lethality. FST288 expression alone did not rescue the neonatal lethality, but mice expressing FST315 on the KO background survived to adulthood with normal lung and skin morphology and partial reversal of the musculoskeletal defects noted in FST KO mice. The FST315 rescue mice displayed a short period of neonatal growth retardation, impaired tail growth, and female infertility. The latter may be due to failure of corpus luteum formation, a decline in the ovarian follicular population, and an augmented uterine inflammatory response to mating. Failure of corpus luteum formation and impaired tail growth indicate abnormal vascularization and suggest that FST288 is required for the promotion of angiogenesis. The augmented uterine inflammatory response may result from the failure of FST315 to modulate the proinflammatory actions of activin A in the uterus or may result from the altered steroid milieu associated with the ovarian abnormalities. Although we cannot definitively conclude that the remaining defects are due to the absence of a particular isoform or due to variable expression of each, these models have demonstrated novel physiological processes that are influenced by FST.

Activin A is a critical component of the inflammatory response, and its binding protein, follistatin, reduces mortality in endotoxemia

Activin A is a member of the transforming growth factor-beta superfamily, which we have identified as having a role in inflammatory responses. We show that circulating levels of activin increase rapidly after LPS-induced challenge through activation of Toll-like receptor 4 and the key adaptor protein, MyD88. Treatment with the activin-binding protein, follistatin, alters the profiles of TNF, IL-1beta, and IL-6 after LPS stimulation, indicating that activin modulates the release of several key proinflammatory cytokines. Further, mice administered one 10-mug dose of follistatin to block activin effects have increased survival after a lethal dose of LPS, and the circulating levels of activin correlate with survival outcome. These findings demonstrate activin A's crucial role in the inflammatory response and show that blocking its actions by the use of follistatin has significant therapeutic potential to reduce the severity of inflammatory diseases.

Genetic screening of infertile men

Male infertility is an extraordinarily common medical condition, affecting 1 in 20 men. According to the World Health Organization, this condition is now considered to be a complex disease involving physical, genetic and environmental factors. With continuing advances in our understanding of male reproductive physiology and endocrinology, together with the availability of the complete sequence of the human genome and powerful functional genomic techniques, the stage is now set to identify the genes that are essential for spermatogenesis. Given that the process of spermatogenesis, from the germ cell to mature sperm, is complex, the challenge for research is to develop the strategies for identifying new genetic causes of idiopathic male infertility and defining genotypes associated with specific defects in semen parameters and testicular pathologies. Such information will form the basis of new genetic tests that will allow the clinician to make an accurate diagnosis of the male partner and a more informed decision about treatment options for the couple.

Cysteine-rich secretory protein 2 binds to mitogen-activated protein kinase kinase kinase 11 in mouse sperm

Cysteine-rich secretory protein (CRISP) 2 (previously TPX1) is a testis-enriched member of the CRISP family, and has been localized to both the sperm acrosome and tail. Like all members of the mammalian CRISP family, its expression pattern is strongly suggestive of a role in male fertility, but functional support for this hypothesis remains limited. In order to determine the biochemical pathways within which CRISP2 is a component, the putative mature form of CRISP2 was used as bait in a yeast two-hybrid screen of a mouse testis expression library. One of the most frequently identified interacting partners was mitogen-activated protein kinase kinase kinase 11 (MAP3K11). Sequencing and deletion experiments showed that the carboxyl-most 20 amino acids of MAP3K11 interacted with the CRISP domain of CRISP2. This interaction was confirmed using pull-down experiments and the cellular context was supported by the localization of CRISP2 and MAP3K11 to the acrosome of the developing spermatids and epididymal spermatozoa. Interestingly, mouse epididymal sperm contained an approximately 60-kDa variant of MAP3K11, which may have been a result of proteolytic cleavage of the longer 93-kDa form seen in many tissues. These data raise the possibility that CRISP2 is a MAP3K11-modifying protein or, alternatively, that MAP3K11 acts to phosphorylate CRISP2 during acrosome development.

Men in Australia Telephone Survey (MATeS): predictors of men's help-seeking behaviour for reproductive health disorders

OBJECTIVE

To identify sociodemographic factors associated with help-seeking behaviour for reproductive health disorders in middle-aged and older Australian men.

DESIGN

A cross-sectional, population-based, computer-assisted telephone interview exploring sociodemographic factors and general and reproductive health.

PARTICIPANTS AND SETTING

Analysis of data from the Men in Australia Telephone Survey (MATeS) of 5990 Australian men aged 40 years and older interviewed between September and December 2003.

MAIN OUTCOME MEASURES

Self-reported diagnosis of prostate disease and erectile dysfunction (ED), help-seeking behaviour (including visiting a doctor, prostate-specific antigen testing, treatment of prostate disease, speaking to a health professional about ED and treatment of ED).

RESULTS

Age was a significant predictor of all help-seeking behaviour studied, other than treatment for ED. Controlling for all predictor variables, never-married status predicted a lower likelihood of visiting a doctor (odds ratio [OR], 0.68 [95% CI, 0.48-0.97]) or speaking to a health professional about ED (OR, 0.44 [95% CI, 0.21-0.93]), while divorced/separated status predicted lower likelihood of having a prostate-specific antigen test (OR, 0.63 [95% CI, 0.50-0.79]). Living in a regional or remote area or being from a non-English-speaking background predicted lower likelihood of receiving treatment for ED (ORs, 0.62 [95% CI, 0.42-0.92] and 0.41 [95% CI, 0.24-0.72], respectively), but did not influence screening for prostate disease.

CONCLUSION

Seeking advice or treatment for male reproductive health disorders is predicted by sociodemographic factors specific to different reproductive health problems. As middle-aged and older men do attend doctors, opportunities exist for health professionals to optimise their consultations by routinely discussing reproductive health with all men, to identify under-reported male reproductive health disorders.

Hypogonadotropism with elevated serum testosterone: reversible causes of secondary infertility

BACKGROUND

A 33-year-old man presented with secondary infertility, increased libido, and extreme oligospermia. Testicular volumes were reduced, but no gynecomastia was apparent and androgen abuse was denied.

INVESTIGATIONS

Physical examination, semen-volume and sperm-density assessment, laboratory tests for serum levels of luteinizing hormone, follicle-stimulating hormone, testosterone, and dehydroepiandrosterone sulfate, karyotyping, testicular ultrasound, pelvic and abdominal CT, assessment for serum testicular tumor markers (alpha-fetoprotein and human chorionic gonadotropin), and histologic examination of testicular tissue.

DIAGNOSIS

Benign Leydig-cell adenoma.

MANAGEMENT

Left orchidectomy.

The relationship between immunosuppressive activity and immunoregulatory cytokines in seminal plasma: influence of sperm autoimmunity and seminal leukocytes

While the contributions of prostasomes, polyamines and prostaglandins to the immunosuppressive activity (ISA) of human seminal plasma have been well-characterised, the contribution of immunoregulatory cytokines found in seminal plasma has received relatively little attention. Semen samples were collected from adult men displaying normospermic parameters, sperm antibodies or substantially elevated seminal leukocytes. Samples were processed through ultracentrifugation and dialysis (<3500Da) to remove prostasomes, polyamines and prostaglandins, and then assayed for ISA by an in vitro T lymphocyte inhibition assay, as well as by specific immunoassays for transforming growth factor beta(1) (TGFbeta(1)), interleukin-10 (IL-10), activin A and the activin-binding protein, follistatin. Seminal plasma from all groups retained substantial ISA following processing. Compared with normospermic men, this 'large' molecular weight ISA fraction was significantly increased in a subset of men with sperm antibodies, but was not altered in the group with elevated leukocytes. There was no relationship between ISA and any cytokine examined, and only TGFbeta(1) was present at levels sufficient to contribute to ISA. Inhibition with a TGFbeta-specific antibody reduced ISA in seminal plasma by approximately 50%. Across all patients, TGFbeta(1) levels were positively correlated with sperm numbers in the ejaculate and with activin A, but not with follistatin or IL-10. Activin A and IL-10 also displayed a positive relationship, and elevated leukocytes was associated with a significant elevation of IL-10 and activin A, but not TGFbeta(1). It is concluded that 'large' molecular weight molecules, the most important of which appears to be TGFbeta(1), make a significant contribution to immunosuppression by human seminal plasma.

Fat aussie--a new Alström syndrome mouse showing a critical role for ALMS1 in obesity, diabetes, and spermatogenesis

Mutations in the human ALMS1 gene are responsible for Alström syndrome, a disorder in which key metabolic and endocrinological features include childhood-onset obesity, metabolic syndrome, and diabetes, as well as infertility. ALMS1 localizes to the basal bodies of cilia and plays a role in intracellular trafficking, but the biological functions of ALMS1 and how these relate to the pathogenesis of obesity, diabetes, and infertility remain unclear. Here we describe a new mouse model of Alström syndrome, fat aussie, caused by a spontaneous mutation in the Alms1 gene. Fat aussie (Alms1 foz/foz) mice are of normal weight when young but, by 120 d of age, they become obese and hyperinsulinemic. Diabetes develops in Alms1 foz/foz mice accompanied by pancreatic islet hyperplasia and islet cysts. Female mice are fertile before the onset of obesity and metabolic syndrome; however, male fat aussie mice are sterile due to a progressive germ cell loss followed by an almost complete block of development at the round-to-elongating spermatid stage of spermatogenesis. In conclusion, Alms1 foz/foz mouse is a new animal model in which to study the pathogenesis of the metabolic and fertility defects of Alström syndrome, including the role of ALMS1 in appetite regulation, pathogenesis of the metabolic syndrome, pancreatic islet physiology, and spermatogenesis.

Follistatin attenuates early liver fibrosis: effects on hepatic stellate cell activation and hepatocyte apoptosis

Activin A, a member of the transforming growth factor-beta superfamily, is constitutively expressed in hepatocytes and regulates liver mass through tonic inhibition of hepatocyte DNA synthesis. Follistatin is the main biological inhibitor of activin bioactivity. These molecules may be involved in hepatic fibrogenesis, although defined roles remain unclear. We studied activin and follistatin gene and protein expression in cultured rat hepatic stellate cells (HSCs) and in rats given CCl4 for 8 wk and examined the effect of follistatin administration on the development of hepatic fibrosis. In activated HSCs, activin mRNA was upregulated with high expression levels, whereas follistatin mRNA expression was unchanged from baseline. Activin A expression in normal lobular hepatocytes redistributed to periseptal hepatocytes and smooth muscle actin-positive HSCs in the fibrotic liver. A 32% reduction in fibrosis, maximal at week 4, occurred in CCl4-exposed rats treated with follistatin. Hepatocyte apoptosis decreased by 87% and was maximal at week 4 during follistatin treatment. In conclusion, activin is produced by activated HSCs in vitro and in vivo. Absence of simultaneous upregulation of follistatin gene expression in HSCs suggests that HSC-derived activin is biologically active and unopposed by follistatin. Our in vivo and in vitro results demonstrate that activin-mediated events contribute to hepatic fibrogenesis and that follistatin attenuates early events in fibrogenesis by constraining HSC proliferation and inhibiting hepatocyte apoptosis.

FGFR-1 [corrected] signaling is involved in spermiogenesis and sperm capacitation

Cloning of the fibroblast growth factor receptor (FGFR) adaptor Snt-2 cDNA and the identification of FGFR-1 protein in association with sperm tails, suggested that FGFR-1 signaling was involved in either sperm tail development or function. This hypothesis was tested by the creation of transgenic mice that specifically expressed a dominant-negative variant of FGFR-1 in male haploid germ cells. Mating of transgenic mice showed a significant reduction in pups per litter compared with wild-type littermates. Further analysis demonstrated that this subfertility was driven by a combination of reduced daily sperm output and a severely compromised ability of those sperm that were produced to undergo capacitation prior to fertilization. An analysis of key signal transduction proteins indicated that FGFR-1 is functional on wild-type sperm and probably signals via the phosphatidylinositol 3-kinase pathway. FGFR-1 activation also resulted in the downstream suppression of mitogen activated protein kinase signaling. These data demonstrate the FGFR-1 is required for quantitatively and qualitatively normal spermatogenesis and has a key role in the regulation of the global tyrosine phosphorylation events associated with sperm capacitation.

Activin A: From sometime reproductive factor to genuine cytokine

The growth factor, activin A, was initially characterized as a putative reproductive hormone but is now known to have many other divergent roles. One of these is during inflammation. Following intravenous injection of bacterial lipopolysaccharide (LPS) into sheep, activin A is released extremely rapidly into the circulation. The release of activin A appears to be independent of fever, prostaglandins or other key proinflammatory cytokines such as TNF-alpha or IL-1beta. While the precise roles and function of this factor in inflammation are yet to be elucidated, the activin response occurs in other mammalian species besides the sheep and elevated activin has been documented for a number of clinical inflammatory conditions. Activin A therefore seems to be part of the regulatory component of the innate immune response.

Men in Australia Telephone Survey (MATeS): a national survey of the reproductive health and concerns of middle-aged and older Australian men

BACKGROUND

The Men in Australia Telephone Survey (MATeS) describes the prevalence of self-reported reproductive health disorders as well as related concerns and health behaviours among middle-aged and older Australian men.

METHODS

A representative sample population (n=5990) of Australian men (>or=40 years) was obtained by contacting a random selection of households with unbiased sampling, stratified by age and state. A 20-min computer-assisted telephone interview was done to assess reproductive health and related knowledge and beliefs, sociodemographic factors, general health, and lifestyle factors.

FINDINGS

A response rate of 78% (5990/7636) was achieved. 34% (1627/4737) of men surveyed reported one or more reproductive health disorder, all of which were most common in the oldest age group. Age-standardised prevalence of significant lower urinary tract symptoms was 16%, erectile dysfunction was 21%, and prostate disease was 14%. About 50% of participants reported having had a prostate cancer test whereas only 30% (300/1012) of men with erectile dysfunction sought medical help. Willingness to seek medical help for erectile dysfunction was related to age and ethnic origin. Although men aged 40-69 years expressed a moderate or high level of concern about prostate cancer and loss of erectile function, concern about reproductive health was less in the oldest age group (>or=70 years).

INTERPRETATION

The high prevalence of reproductive health disorders and associated concerns in middle-aged and older Australian men draws attention to the need to develop appropriate services and education strategies specifically directed to improving reproductive health in these men.

Cytokine profiles in the testes of rats treated with lipopolysaccharide reveal localized suppression of inflammatory responses

Evidence indicates that the testis possesses a reduced capacity to mount inflammatory and rejection responses, which undoubtedly contributes to the ongoing survival of the highly immunogenic germ cells. The contribution of local cytokine expression to this condition was investigated in adult male rats treated with lipopolysaccharide to induce inflammation. Cytokine mRNA and protein expression were determined in tissue extracts and fluids by Northern blot analysis, quantitative PCR, or RNAse protection assay and specific ELISAs. Testicular expression of the proinflammatory cytokines, interleukin (IL)-1β and tumor necrosis factor-α was considerably attenuated compared with the liver (control tissue); in contrast, the testicular IL-6 response was enhanced. Expression of IL-10, a type 2 immunoregulatory cytokine, was similar in both testis and liver, whereas the immunoregulatory/anti-inflammatory cytokines transforming growth factor-β1and activin A were constitutively elevated in both normal and inflamed testes. The IL-1β and transforming growth factor-β1proteins were present principally in their latent (inactive) forms, indicating that enzymic processing is an important control mechanism for these two cytokines within the testis. These data indicate that inflammatory and regulatory cytokine activity is regulated at both transcriptional and posttranslational levels in a testis-specific manner. It is concluded that a novel pattern of suppression of proinflammatory cytokine responses and normal or elevated expression of immunoregulatory cytokines may be responsible for reduced inflammatory responses and enhanced graft survival in the testis. These data have important implications for the understanding and treatment of male autoimmune infertility, testicular inflammation. and carcinogenesis.

Meiotic and epigenetic defects in Dnmt3L-knockout mouse spermatogenesis

The production of mature germ cells capable of generating totipotent zygotes is a highly specialized and sexually dimorphic process. The transition from diploid primordial germ cell to haploid spermatozoa requires genome-wide reprogramming of DNA methylation, stage- and testis-specific gene expression, mitotic and meiotic division, and the histone-protamine transition, all requiring unique epigenetic control. Dnmt3L, a DNA methyltransferase regulator, is expressed during gametogenesis, and its deletion results in sterility. We found that during spermatogenesis, Dnmt3L contributes to the acquisition of DNA methylation at paternally imprinted regions, unique nonpericentric heterochromatic sequences, and interspersed repeats, including autonomous transposable elements. We observed retrotransposition of an LTR-ERV1 element in the DNA from Dnmt3L-/- germ cells, presumably as a result of hypomethylation. Later in development, in Dnmt3L-/- meiotic spermatocytes, we detected abnormalities in the status of biochemical markers of heterochromatin, implying aberrant chromatin packaging. Coincidentally, homologous chromosomes fail to align and form synaptonemal complexes, spermatogenesis arrests, and spermatocytes are lost by apoptosis and sloughing. Because Dnmt3L expression is restricted to gonocytes, the presence of defects in later stages reveals a mechanism whereby early genome reprogramming is linked inextricably to changes in chromatin structure required for completion of spermatogenesis.

Identification of a novel apolipoprotein, ApoN, in ovarian follicular fluid

A novel apolipoprotein, designated ApoN, has been identified in bovine ovarian follicular fluid using chromatographic purification methods, amino acid sequence analysis, molecular biology, and bioinformatics. The apolipoprotein is a hydrophobic 12-kDa protein processed from the C terminus of a 29-kDa precursor expressed in a number of tissues, including the ovary, testis, the anterior chamber of the eye, skeletal muscle, uterus, and liver. Bovine, porcine, and murine ApoN display significant homology at the amino acid level across the entire precursor sequence. Surprisingly, there appears to be no orthologous protein in the human, although an APON-like pseudogene is found on chromosome 12. The N-terminal fragment of the ApoN precursor shows significant homology with the N-terminal sequence of the precursor of the cholesterol transport regulatory protein ApoF, but the corresponding C-terminal sequences of ApoN and ApoF possess no homology. ApoN is present in the high-density lipoprotein fraction of bovine serum and both the high-density lipoprotein and low-density lipoprotein fractions of bovine follicular fluid and is found in several tissues that are associated with local immunological privilege. These data suggest that ApoN may play a role in steroidogenesis and/or immunoregulation in the gonads of nonhuman species, as well as similar roles in other tissues.

Activin A and follistatin in systemic inflammation

Inflammation is a complex process regulated by a cascade of cytokines and growth factors. This review summarizes the emerging evidence implicating activin A and follistatin in the inflammatory process. Our recent studies have highlighted that activin A is released early in the process as part of the circulatory cytokine cascade during acute systemic inflammation. This release occurs concurrently with tumor necrosis factor (TNF)-alpha and prior to that of interleukin (IL)-6 and follistatin. Although, the cellular source(s) of activin A are yet to be established, circulating blood cells and the vascular endothelium are candidates for this rapid release of activin A into the circulation. The release of activin A and follistatin is also observed in the clinical setting, in particular in sepsis. Furthermore activin A is released into cerebrospinal fluid in a model of meningitis in rabbits. The role of activin A in the inflammatory response is poorly understood, however, in vitro data has highlighted that activin A can have both pro- and anti-inflammatory actions on key mediators of the inflammatory response such as TNF-alpha, IL-1beta and IL-6. Furthermore, emerging data would suggest that activin A induction is restricted to certain types of inflammation and its release is dependant upon the inflammatory setting.

Changes in circulating and testicular levels of inhibin A and B and activin A during postnatal development in the rat

This study describes the testicular levels of inhibin/activin subunits by Northern analysis and in situ hybridization and serum and testicular levels of inhibins A and B and activin A by enzyme linked immunosorbent assays (ELISA) during postnatal development in the rat. We show that serum inhibin A levels are less than 4 pg/ml throughout postnatal life. Serum inhibin B levels peak at 572 +/- 119 pg/ml (mean +/- se) at d 40 post partum (pp) before falling to 182 +/- 35 pg/ml in mature males. Serum activin A decreases from 294 +/- 29 pg/ml at d 6 to 132 +/- 27 pg/ml at maturity. Within the testis, inhibin A levels fall from 0.330 +/- 0.108 ng/g at d 15 to less than 0.004 ng/g at maturity. Inhibin B levels peak at 43.9 +/- 4.2 ng/g at d 6 before falling to 1.6 +/- 0.13 ng/g at maturity. Testicular activin A levels fall from 18.6 +/- 2.2 ng/g at d 6 to 0.094 +/- 0.013 ng/g at maturity. Northern profiles of testicular inhibin/activin subunits correlate with immunoreactive levels demonstrated by ELISA. In situ hybridization suggests that beta(A) and beta(B) subunit expression is largely restricted to the seminiferous tubule, particularly Sertoli cells, spermatogonia, and primary spermatocytes. These data support the view that inhibin B is the major inhibin in the male rat and that levels relate to Sertoli cell number and activity. Furthermore, the demonstration of high local concentrations of activin A during the period of Sertoli cell proliferation and the onset of spermatogenesis support its proposed role because a modulator of testicular development and function.