Intravascular Follistatin gene delivery improves glycemic control in a mouse model of type 2 diabetes.

Type 2 diabetes (T2D) manifests from inadequate glucose control due to insulin resistance, hypoinsulinemia, and deteriorating pancreatic ß-cell function. The pro-inflammatory factor Activin has been implicated as a positive correlate of severity in T2D patients, and as a negative regulator of glucose uptake by skeletal muscle, and of pancreatic ß-cell phenotype in mice. Accordingly, we sought to determine whether intervention with the Activin antagonist Follistatin can ameliorate the diabetic pathology. Here, we report that an intravenous Follistatin gene delivery intervention with tropism for striated muscle reduced the serum concentrations of Activin B and improved glycemic control in the db/db mouse model of T2D. Treatment reversed the hyperglycemic progression with a corresponding reduction in the percentage of glycated-hemoglobin to levels similar to lean, healthy mice. Follistatin gene delivery promoted insulinemia and abundance of insulin-positive pancreatic ß-cells, even when treatment was administered to mice with advanced diabetes, supporting a mechanism for improved glycemic control associated with maintenance of functional ß-cells. Our data demonstrate that single-dose intravascular Follistatin gene delivery can ameliorate the diabetic progression and improve prognostic markers of disease. These findings are consistent with other observations of Activin-mediated mechanisms exerting deleterious effects in models of obesity and diabetes, and suggest that interventions that attenuate Activin signaling could help further understanding of T2D and the development of novel T2D therapeutics.

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.

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.

Late gastrointestinal effects of pelvic radiation: a nurse-led service.

There are currently at least 2 million people in the UK living with and following a cancer diagnosis. Typically four out of every ten people with cancer will receive radiotherapy, but a large proportion of people who have pelvic radiotherapy may go on to develop gastrointestinal (GI) symptoms. This includes rectal bleeding and faecal incontinence, which can have a huge impact on quality of life. These problems often go under-reported by patients and are also under-recognised or under-treated by health professionals. Cancer survivorship is a growing topic that is likely to have a major impact on the NHS, with increasing numbers of patients presenting. A late GI effects of pelvic radiotherapy clinic was set up to address these growing needs of patients with GI symptoms following radiotherapy. This article also shares insights from a doctoral study that is underway looking at people's experiences of living with symptoms following their treatment, in order to improve awareness of the major impact that this can have.

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.

Serum activin A and B levels predict outcome in patients with acute respiratory failure: a prospective cohort study.

INTRODUCTION: 30 day mortality in patients with Acute Respiratory Failure (ARF) is approximately 30%, defined as patients requiring ventilator support for more than 6 hours. Novel biomarkers are needed to predict patient outcomes and to guide potential future therapies. The activins A and B, members of the Transforming Growth Factor ß family of proteins, and their binding protein, follistatin, have recently been shown to be important regulators of inflammation and fibrosis but no substantial data are available concerning their roles in ARF. METHODS: Specific assays for activin A, B and follistatin were used and the results analyzed according to diagnostic groups as well as according to standard measures in intensive care. Multivariable logistic regression was used to create a model to predict death at 90 days and 12 months from the onset of the ARF. RESULTS: Serum activin A and B were significantly elevated in most patients and in most of the diagnostic groups. Patients who had activin A and/or B concentrations above the reference maximum were significantly more likely to die in the 12 months following admission [either activin A or B above reference maximum: Positive Likelihood Ratio [LR+] 1.65 [95% CI 1.28-2.12, P = 0.00013]; both activin A and B above reference maximum: LR + 2.78 [95% CI 1.96-3.95, P < 0.00001]. The predictive model at 12 months had an overall accuracy of 80.2% [95% CI 76.6-83.3%]. CONCLUSIONS: The measurement of activin A and B levels in these patients with ARF would have assisted in predicting those at greatest risk of death. Given the existing data from animal studies linking high activin A levels to significant inflammatory challenges, the results from this study suggest that approaches to modulate activin A and B bioactivity should be explored as potential therapeutic agents.

A Systematic Review of Population-Based Studies of Chronic Bowel Symptoms in Cancer Survivors following Pelvic Radiotherapy.

Pelvic radiotherapy can damage surrounding tissue and organs, causing chronic conditions including bowel symptoms. We systematically identified quantitative, population-based studies of patient-reported bowel symptoms following pelvic radiotherapy to synthesize evidence of symptom type, prevalence, and severity. Medline, CINAHL, EMBASE, and PsychINFO were searched from inception to September 2022. Following independent screening of titles, abstracts, and full-texts, population and study characteristics and symptom findings were extracted, and narrative synthesis was conducted. In total, 45 papers (prostate, n = 39; gynecological, n = 6) reporting 19 datasets were included. Studies were methodologically heterogeneous. Most frequently assessed was bowel function ('score', 26 papers, 'bother', 19 papers). Also assessed was urgency, diarrhea, bleeding, incontinence, abdominal pain, painful hemorrhoids, rectal wetness, constipation, mucous discharge, frequency, and gas. Prevalence ranged from 1% (bleeding) to 59% (anal bleeding for >12 months at any time since start of treatment). In total, 10 papers compared radiotherapy with non-cancer comparators and 24 with non-radiotherapy cancer patient groups. Symptom prevalence/severity was greater/worse in radiotherapy groups and symptoms more common/worse post-radiotherapy than pre-diagnosis/treatment. Symptom prevalence varied between studies and symptoms. This review confirms that many people experience chronic bowel symptoms following pelvic radiotherapy. Greater methodological consistency, and investigation of less-well-studied survivor populations, could better inform the provision of services and support.

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.

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.

Cardio-respiratory fitness, habitual physical activity and serum brain derived neurotrophic factor (BDNF) in men and women.

Short episodes of high intensity exercise transiently increase serum levels of BDNF in humans, but serum levels of BDNF at rest appear to be lower in more physically active humans with greater levels of energy expenditure. The relationship between serum BDNF concentration, cardio-respiratory fitness (Astrand-Rhyming test estimated VO2 max) and volume of long-term, regular exercise and sporting activity (Baecke Habitual Physical Activity Index) was investigated in 44 men and women between the age range of 18-57 years. In this group an inverse relationship between resting serum BDNF concentration and measures of both estimated VO2 max (r=-0.352; P<0.05) and long-term sporting activity (r=-0.428, P<0.01) was found. These results indicate that increased levels of cardio-respiratory fitness and habitual exercise are associated with lower resting levels of serum BDNF in healthy humans. This is the first study to demonstrate an inverse relationship between a physiological estimate of cardio-respiratory fitness and serum BDNF.

Using email and text messaging to improve patient compliance with blood monitoring.

BACKGROUND: Patients with inflammatory bowel disease may need immunosuppressant therapy. This involves frequent blood tests to ensure results are within safe limits. AIM: To investigate whether the use of email and text messaging to remind patients to have blood tests might result in better compliance than using more conventional methods of communication. METHOD: Patients were divided into three groups by self-selection: one wanted email reminders; one wanted texts; while a control group received telephone calls and letters. Data on the delays was analysed. RESULTS: In all groups receiving email, text messages or traditional phone call reminders, delays were reduced. Patients in the email/text messaging groups overwhelmingly found these methods helpful and wished them to continue. DISCUSSION AND CONCLUSION: The use of email and text messaging helped to reduce delays in monitoring and patients who selected these methods found it helpful. We aim to continue this service.

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.

Assessment of steroid use as a key performance indicator in inflammatory bowel disease-analysis of data from 2385 UK patients.

BACKGROUND: Patients with IBD are at risk of excess corticosteroids. AIMS: To assess steroid excess in a large IBD cohort and test associations with quality improvement and prescribing. METHODS: Steroid exposure was recorded for outpatients attending 19 centres and associated factors analysed. Measures taken to avoid excess were assessed. RESULTS: Of 2385 patients, 28% received steroids in the preceding 12 months. 14.8% had steroid excess or dependency. Steroid use was significantly lower at 'intervention centres' which participated in a quality improvement programme (exposure: 23.8% vs 31.0%, P < .001; excess 11.5% vs 17.1%, P < .001). At intervention centres, steroid use fell from 2015 to 2017 (steroid exposure 30.0%-23.8%, P = .003; steroid excess 13.8%-11.5%, P = .17). Steroid excess was judged avoidable in 50.7%. Factors independently associated with reduced steroid excess in Crohn's disease included maintenance with anti-TNF agents (OR 0.61 [95% CI 0.24-0.95]), treatment in a centre with a multi-disciplinary team (OR 0.54 [95% CI 0.20-0.86]) and treatment at an intervention centre (OR 0.72 [95% CI 0.46-0.97]). Treatment with 5-ASA in CD was associated with higher rates of steroid excess (OR 1.72 [95% CI 1.24-2.09]). In ulcerative colitis (UC), thiopurine monotherapy was associated with steroid excess (OR 1.97 [95% CI 1.19-3.01]) and treatment at an intervention centre with less steroid excess (OR 0.72 [95% CI 0.45-0.95]). CONCLUSIONS: This study validates steroid assessment as a meaningful quality measure and provides a benchmark for this performance indicator in a large cohort. A programme of quality improvement was associated with lower steroid use.

Development of a new antibody to the human inhibin/activin betaB subunit and its application to improved inhibin B ELISAs.

Inhibin B has emerged as a clinically useful analyte for studies of reproductive function in both men and women. The antibody to the betaB subunit (C5) used in current commercially available assays (DSL and OBI) was raised in this laboratory to a synthetic peptide from the betaB subunit. These assays require pre-treatment of samples with hydrogen peroxide to oxidise two methionines in the epitope to the sulfoxide for full immunoreactivity. It was also claimed that this antibody cross-reacted significantly with inhibin A leading to a 0.5% cross-reaction of inhibin A in the current generation of immunoassays. Both of the above immunoassays required overnight incubation with sample. The development of improved antibodies to the betaB subunit has proved difficult due to the conservation of the betaB subunit between species. We describe the development of new monoclonal antibodies to the betaB subunit, by immunisation of mice with recombinant X. laevis activin B using the RIMMS method of immunisation. The result has been the development of highly specific antibodies in a short time period. One of these antibodies 46A/F is shown to be a highly effective capture antibody in a human inhibin B ELISA, without any sample pre-treatment. The results of the validation of an improved inhibin B assay using 46A/F as the capture antibody are shown, with comparison to one of the commercially available inhibin B assays. Overall, the inhibin B assay is simplified and the performance improved by using this new antibody 46A/F. It was further shown that the cross-reaction of inhibin A in both the OBI and DSL inhibin B ELISAs is ten fold less than previously reported. This can be attributed to the poor quality of recombinant inhibin B available for use as standard in 1996. Although the present generation of inhibin B assays has proved adequate to enable the physiological function of inhibin to be determined and novel clinical applications found, the simplification of the assay made possible by the improved antibody should make possible a new generation of more rapid, sensitive, convenient and robust tools for routine use.

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.

7alpha-methyl-19-nortestosterone (MENT) vs testosterone in combination with etonogestrel implants for spermatogenic suppression in healthy men.

Testosterone with a progestogen can suppress spermatogenesis for contraception. The synthetic androgen 7alpha-methyl-19-nortestosterone (MENT) may offer advantages because it is resistant to 5alpha-reduction and is therefore less active at the prostate. This study aimed to investigate MENT implants in combination with etonogestrel on spermatogenesis, gonadotropins, and androgen-dependent tissues in comparison with a testosterone/etonogestrel regimen. Healthy men (n = 29) were recruited and randomized to receive 2 etonogestrel implants with either 600-mg testosterone pellets repeated every 12 weeks or 2 MENT implants for up to 48 weeks. Testosterone concentrations in the testosterone group remained in the normal range. Subjects with 2 MENT implants showed peak MENT levels at 4 weeks with testosterone concentrations of 2 nmol/L. Sperm concentrations fell rapidly to less than 1 x 10(6)/mL at 12 weeks in 8 of 10 subjects in the MENT group and 13 of 16 subjects in the testosterone group with equally suppressed gonadotropins. Thereafter, suppression was not maintained in the MENT group, and 6 men noted loss of libido. Fourteen men completed 48 weeks of testosterone treatment, and all became azoospermic. Hemoglobin concentrations rose, and high density lipoprotein-cholesterol (HDL-C) fell in both groups. The MENT group showed a fall in prostate-specific antigen with no change in bone mass. MENT with a progestogen can achieve rapid suppression of spermatogenesis similar to testosterone, but this promising result was not sustained due to a decline in MENT release from the implants. This dose of testosterone, compared with previous studies using a lower dose with a higher dose of etonogestrel, had nonreproductive side effects without any increase in spermatogenic suppression. These data indicate the importance of the doses of progestogen and testosterone for optimum spermatogenic suppression while minimizing side effects.

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 Ins2Akita+/- 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. Ins2Akita+/- 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 Ins2Akita+/- mice leads to progressive testicular disruption mediated by testicular activin activity, rather than hormonal dysregulation.

Testicular activin and follistatin levels are elevated during the course of experimental autoimmune epididymo-orchitis in mice.

Experimental autoimmune epididymo-orchitis (EAEO) is a model of chronic inflammation, induced by immunisation with testicular antigens, which reproduces the pathology of some types of human infertility. Activins A and B regulate spermatogenesis and steroidogenesis, but are also pro-inflammatory, pro-fibrotic cytokines. Expression of the activins and their endogenous antagonists, inhibin and follistatin, was examined in murine EAEO. Adult untreated and adjuvant-treated control mice showed no pathology. All mice immunised with testis antigens developed EAEO by 50 days, characterised by loss of germ cells, immune cell infiltration and fibrosis in the testis, similar to biopsies from human inflamed testis. An increase of total CD45+ leukocytes, comprising CD3+ T cells, CD4 + CD8- and CD4 + CD25+ T cells, and a novel population of CD4 + CD8+ double positive T cells was also detected in EAEO testes. This was accompanied by increased expression of TNF, MCP-1 and IL-10. Activin A and B and follistatin protein levels were elevated in EAEO testes, with peak activin expression during the active phase of the disease, whereas mRNA expression of the inhibin B subunits (Inha and Inhbb) and activin receptor subunits (Acvr1b and Acvr2b) were downregulated. These data suggest that activin-follistatin regulation may play a role during the development of EAEO.