Effect of testosterone on hepcidin, ferroportin, ferritin and iron binding capacity in patients with hypogonadotropic hypogonadism and type 2 diabetes

Distinct Clusters of Testosterone Levels, Symptoms, and Serum Trace Elements in Young Men: A Cross-Sectional Analysis

Background/Objectives: Modern societal stressors have been linked to declining testosterone levels among young men, contributing to somatic, psychological, and sexual health problems. Despite growing evidence suggesting a link between trace elements and testosterone-related symptoms, there are only a few comprehensive analyses on younger populations. This study's aim was to examine how serum trace elements modulate the relationship between testosterone levels and symptom severity. Methods: This cross-sectional study included 225 young men seeking infertility consultation in Japan. Serum total and free testosterone levels were measured, along with self-reported symptoms using the Aging Males' Symptoms scale (somatic, psychological, sexual) and the Erection Hardness Score. The serum concentrations of 20 trace elements were measured. We used unsupervised clustering to classify participants based on testosterone levels and symptom severity and then compared the distribution of trace elements among the resulting clusters. Results: Three distinct clusters emerged: (1) lowest testosterone with highest symptom severity, (2) intermediate, and (3) highest testosterone with minimal symptoms. Interestingly, the intermediate cluster displayed low testosterone levels but minimal symptoms. Eleven trace elements (phosphorus, sulfur, potassium, calcium, iron, zinc, arsenic, rubidium, strontium, molybdenum, and cesium) were identified as potential contributors to testosterone dynamics. Weighted quantile sum regression indicated that phosphorus, strontium, and molybdenum negatively influenced testosterone outcomes, whereas iron, sulfur, and zinc were beneficial. Conclusions: Serum trace element profiles are significantly associated with testosterone levels and symptom severity in young men. Targeted interventions may address testosterone decline and its implications. These findings may help develop tailored strategies for optimizing male health.

Testosterone and Erythrocyte Lifespan

CONTEXT

Endogenous and exogenous androgens increase circulating erythrocytes and hemoglobin but their effects on erythrocyte lifespan is not known.

OBJECTIVE

To investigate androgen effects on immature and mature erythrocyte lifespan in humans and mice using novel nonradioactive minimally invasive methods.

DESIGN

Human erythrocyte lifespan was estimated using alveolar carbon monoxide concentration and blood hemoglobin in Levitt's formula in hypogonadal or transgender men before and up to 18 weeks after commencing testosterone (T) treatment. Erythrocyte lifespan was estimated in androgen receptor knockout and wild-type mice after T or DHT treatment of intact females or orchidectomized males using in vivo biotin labelling of erythrocyte surface epitopes for reticulocytes (Ter119+CD71+) and 2 markers of erythrocytes (CD45-, Ter119+CD71-) monitoring their blood disappearance rate by flow cytometry.

RESULTS

Before treatment, hypogonadal and transgender men had marked reduction in erythrocyte lifespan compared with controls. T treatment increased erythrocyte lifespan at 6 weeks but returned to pretreatment levels at 18 weeks, whereas serum T and blood hemoglobin were increased by T treatment remaining elevated at 18 weeks. In mice, T and DHT treatment had higher erythrocyte (but not reticulocyte) lifespan but neither orchidectomy nor androgen receptor inactivation significantly influenced erythrocyte or reticulocyte lifespan.

CONCLUSION

We conclude that hypogonadal men have reduced erythrocyte lifespan and acute androgen-induced increase in circulating erythrocyte lifespan may contribute to the well-known erythropoietic effects of androgens, but longer term effects require further investigation to determine how much they contribute to androgen-induced increases in circulating hemoglobin.

Increased risk of erythrocytosis in men with type 2 diabetes treated with combined sodium-glucose cotransporter-2 inhibitor and testosterone replacement therapy

PURPOSE

In clinical trials, sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and testosterone replacement therapy (TRT) were shown to stimulate red blood cell production. Little is known if combination therapy poses risk of erythrocytosis in real world clinical practice.

METHODS

This was a retrospective nationwide cohort study of US Veterans with type 2 diabetes (T2D) and baseline hematocrit between 38 and 50% who were prescribed SGLT-2i and/or TRT between 3/2013 and 10/2022 and had adequate adherence based on the proportion of days covered > 80%. Patients were divided into 3 groups: SGLT-2i only, TRT only, or combination therapy. Odds Ratio (OR) of new erythrocytosis defined as hematocrit level > 54% within 365 days of therapy initiation was calculated by logistic regression model adjusted for baseline hematocrit, age, BMI, obstructive sleep apnea, diuretic use, and smoking status.

RESULTS

Of the entire cohort of 53,971 people with T2D, total of 756 (1.4%) patients developed erythrocytosis. In unadjusted analyses, the OR of new onset erythrocytosis was higher in the combined SGLT-2i and TRT group compared with the SGLT-2i or TRT group alone (4.99, 95% CI (3.10-7.71) and 2.91, 95% CI (1.87-4.31), respectively). In the models adjusted for baseline characteristics, patients on combination therapy had significantly higher odds of erythrocytosis compared to those on SGLT-2i (OR 3.80, 95% CI (2.27-6.11)) or TRT alone (OR 2.49, 95% CI (1.51-3.59)). Testosterone delivery route (topical vs injectable) did not modify increased odds of erythrocytosis.

CONCLUSIONS

For the first time, we demonstrated that in large cohort of patients combined therapy with SGLT-2i and TRT is associated with increased erythrocytosis risk compared with either treatment alone. Given rising prevalence of SGLT-2i use, providers should consider periodic hematocrit assessment in persons receiving both SGLT-2i and TRT.

Management of male obesity-related secondary hypogonadism: A clinical update

The global obesity pandemic has resulted in a rise in the prevalence of male obesity-related secondary hypogonadism (MOSH) with emerging evidence on the role of testosterone therapy. We aim to provide an updated and practical approach towards its management. We did a comprehensive literature search across MEDLINE (via PubMed), Scopus, and Google Scholar databases using the keywords "MOSH" OR "Obesity-related hypogonadism" OR "Testosterone replacement therapy" OR "Selective estrogen receptor modulator" OR "SERM" OR "Guidelines on male hypogonadism" as well as a manual search of references within the articles. A narrative review based on available evidence, recommendations and their practical implications was done. Although weight loss is the ideal therapeutic strategy for patients with MOSH, achievement of significant weight reduction is usually difficult with lifestyle changes alone in real-world practice. Therefore, androgen administration is often necessary in the management of hypogonadism in patients with MOSH which also improves many other comorbidities related to obesity. However, there is conflicting evidence for the appropriate use of testosterone replacement therapy (TRT), and it can also be associated with complications. This evidence-based review updates the available evidence including the very recently published results of the TRAVERSE trial and provides comprehensive clinical practice pearls for the management of patients with MOSH. Before starting testosterone replacement in functional hypogonadism of obesity, it would be desirable to initiate lifestyle modification to ensure weight reduction. TRT should be coupled with the management of other comorbidities related to obesity in MOSH patients. Balancing the risks and benefits of TRT should be considered in every patient before and during long-term management.

Hepcidin Reduction during Testosterone Therapy in Men with Type 2 Diabetes: A Randomized, Double-Blinded, Placebo-Controlled Study

High hepcidin is linked to low-grade inflammation and lower iron levels. The consequences of testosterone replacement therapy (TRT) on inflammation and the risk of cardiovascular disease (CVD) are undetermined. We investigate the effect of TRT on the inflammatory cardiovascular risk markers hepcidin-iron, fibroblast growth factor 23 (FGF23)-phosphate-klotho, and calprotectin pathways.

METHODS

A randomized, placebo-controlled, double-blinded study at an academic tertiary-care medical center. Interventions were testosterone gel (TRT, n = 20) or placebo gel (n = 19) for 24 weeks. We included 39 men (50-70 years) with type 2 diabetes (T2D) on metformin monotherapy with bioavailable testosterone levels <7.3 nmol/L. Body composition was assessed with DXA- and MRI-scans; the main study outcomes were serum hepcidin-iron, FGF23, phosphate, klotho, and calprotectin.

RESULTS

Hepcidin levels decreased during TRT (β = -9.5 ng/mL, p < 0.001), lean body mass (β = 1.9 kg, p = 0.001) increased, and total fat mass (β = -1.3 kg, p = 0.009) decreased compared to placebo. Delta hepcidin was not associated with changes in lean body mass or fat mass. Iron and the pathways of FGF23-phosphate-klotho and calprotectin were unchanged during TRT.

CONCLUSIONS

During TRT, the reduction in hepcidin was not associated with circulating iron levels, lean body mass, or fat mass; these findings suggested a direct anti-inflammatory effect of TRT and no indirect effect mediated through these factors.

Association of serum hepcidin with prostate-specific antigen levels in men from high Andean cities of Peru

Objective

The prostate-specific antigen (PSA) is the primary biomarker to diagnose prostate cancer. Hepcidin has been reported as an alternative for this diagnosis; however, it is unclear how PSA and hepcidin function at high altitude (HA). This study aims to assess the association between hepcidin with PSA in HA residents chronically exposed to hypobaric hypoxia.

Methods

We retrospectively examined data of 70 healthy males (aged 18-65-years-old) from four different altitudes cities in Peru: Lima (<150 m), Huancayo (2380 m), Puno (3800 m), and Cerro de Pasco (4320 m). Serum hepcidin, testosterone, and PSA were analyzed by chemiluminescence immunoassay. HA parameters (hemoglobin [Hb], pulse oxygen saturation [SpO2], and chronic mountain sickness [CMS] score) were also included in the study. Bivariate analyses and a multivariate linear mixed model were used to evaluate the association between hepcidin and PSA, adjusted by HA parameters, age, and body mass index (BMI).

Results

Cases of excessive erythrocytosis (EE) (Hb >21 g/dL) were observed in the three highest cities. Hepcidin was positively correlated with Hb, CMS score, and BMI (P ≤ 0.05). Hepcidin was higher in Huancayo with respect to Puno, while PSA was lower in Cerro de Pasco in regard to Puno and Lima (P ≤ 0.05). Neither hepcidin nor PSA was increased by altitude in each city (P > 0.05). We did not find an association between hepcidin and PSA, even adjusted by age, BMI, Hb, and SpO2 (P ≤ 0.05).

Conclusion

These findings showed no association between hepcidin and PSA levels in healthy residents at HA.

Impact of testosterone therapy on bone turnover markers in obese males with type 2 diabetes and functional hypogonadism

METHODS

Fifty-five obese males with type 2 diabetes mellitus and functional hypogonadism participated in a 2-year, double-blind, placebo-controlled study of testosterone undecanoate (TU). Bone turnover markers C-telopeptide of type I collagen (CTX) and procollagen I N-terminal propeptide (PINP) were assessed at baseline, 12 and 24 months. Bone mineral density (BMD) changes were evaluated after 24 months using dual-energy X-ray absorptiometry. Group T (n = 28) received TU both years. Group P (n = 27) received placebo first year and TU second year.

RESULTS

CTX decreased in group P from 1055 (676-1344) to 453 (365-665) pmol/L (p < 0.001) and from 897 (679-1506) to 523 (364-835) pmol/L (p < 0.001) in T. PINP decreased by 4.30 ± 8.05 μg/L in group P (p = 0.030) and 4.64 ± 8.86 μg/L in T (p < 0.023) after first year of therapy. No femoral neck BMD changes were observed in 32 patients from both groups (n = 16 per group). Lumbar spine BMD increased (by 0.075 ± 0.114 g/cm²; p = 0.019) in group T following two years of treatment.

CONCLUSIONS

We observed decreased CTX, decreased PINP and increased lumbar spine BMD after two years of testosterone treatment.

CLINICAL TRIALS

NCT03792321; retrospectively registered trial on 4 January 2019.

Therapeutic effects of androgens for cachexia

Cachexia is a complex wasting syndrome, accompanying a variety of end-stage chronic diseases, such as cancer, heart failure and human immunodeficiency virus (HIV) infection/acquired immunodeficiency syndrome (AIDS). It significantly affects patients' quality of life and survival. Multiple therapeutic approaches have been studied over time. However, despite promising results, no drug has been approved to date. In this review, we examine and discuss the available data on the therapeutic effects of androgens and selective androgen receptor modulators (SARMs) for cachexia.

Haematological actions of androgens

In this review, we discuss the effects on androgens on the haemopoietic system, focussing largely on the effects of testosterone on erythropoiesis. Stimulation of erythropoiesis is one of the most consistent effects of testosterone treatment observed in clinical trials. In men with anaemia this effect can be beneficial. Conversely, erythrocytosis is one of the most common adverse effects of testosterone treatment with a relative risk of 8.14 (95% CI: 1.87-35.40) estimated by a recent meta-analysis of randomised placebo controlled clinical trials. A reduction in haemoglobin is commonly seen in men receiving androgen deprivation therapy for prostate cancer, and in transwomen receiving gender affirming therapy to reduce serum testosterone. While mechanisms by which androgens regulate erythropoiesis are not fully understood, it is likely that effects on erythropoietic progenitor cells and erythropoietin are involved, with secondary effects on iron metabolism. In contrast, whether androgens exert clinically relevant effects on white blood cells and on platelets requires further study.

High altitude exposure affects male reproductive parameters: Could it also affect the prostate?†

Living at high altitudes and living with prostatic illness are two different conditions closely related to a hypoxic environment. People at high altitudes exposed to acute, chronic, or intermittent hypobaric hypoxia turn on several mechanisms at the system, cellular and molecular level to cope with oxygen atmosphere scarcity maintaining the oxygen homeostasis. This exposure affects the whole organism and function of many systems, such as cardiovascular, respiratory, and reproductive. On the other hand, malignant prostate is related to the scarcity of oxygen in the tissue microenvironment due to its low availability and high consumption due to the swift cell proliferation rates. Based on the literature, this similarity in the oxygen scarcity suggests that hypobaric hypoxia, and other common factors between these two conditions, could be involved in the aggravation of the pathological prostatic status. However, there is still a lack of evidence in the association of this disease in males at high altitudes. This review aims to examine the possible mechanisms that hypobaric hypoxia might negatively add to the pathological prostate function in males who live and work at high altitudes. More profound investigations of hypobaric hypoxia's direct action on the prostate could help understand this exposure's effect and prevent worse prostate illness impact in males at high altitudes.

Dietary Micronutrients from Zygote to Senility: Updated Review of Minerals' Role and Orchestration in Human Nutrition throughout Life Cycle with Sex Differences

Micronutrients such as selenium, fluoride, zinc, iron, and manganese are minerals that are crucial for many body homeostatic processes supplied at low levels. The importance of these micronutrients starts early in the human life cycle and continues across its different stages. Several studies have emphasized the critical role of a well-balanced micronutrient intake. However, the majority of studies looked into or examined such issues in relation to a specific element or life stage, with the majority merely reporting the effect of either excess or deficiency. Herein, in this review, we will look in depth at the orchestration of the main element requirements across the human life cycle beginning from fertility and pregnancy, passing through infancy, childhood, adolescence, and reaching adulthood and senility, with insight on the interactions among them and underlying action mechanisms. Emphasis is given towards approaches to the role of the different minerals in the life cycle, associated symptoms for under- or overdoses, and typical management for each element, with future perspectives. The effect of sex is also discussed for each micronutrient for each life stage as literature suffice to highlight the different daily requirements and or effects.

Effects of a Novel Oral Testosterone Undecanoate on Ambulatory Blood Pressure in Hypogonadal Men

BACKGROUND

Testosterone replacement therapies may increase blood pressure (BP) with chronic use but the mechanism is not clear. TLANDO™ is a new oral testosterone undecanoate (TU) under development for the treatment of male hypogonadism.

METHODS

We studied the effects of the TU at 225 mg twice daily on ambulatory BP (ABP) and heart rate, in 138 men with hypogonadism (mean age, 54 years, 79% white, 48% with hypertension). Ambulatory BP and heart rate and hematologic assessments were obtained at baseline and following 4-months of therapy.

RESULTS

Changes from baseline in ambulatory 24-hour, awake, and sleep systolic BP (SBP) of 3.8 (P < 0.001), 5.2 (P < 0.001), and 4.3 mmHg (P = 0.004) were observed post-treatment, respectively. Lesser changes in the diastolic BP (DBP) were observed (1.2 (P = 0.009), 1.7 (P = 0.004), and 1.7 mmHg (P = 0.011) for 24-hour, awake, and sleep, respectively). Hematocrit and hemoglobin were increased by 3.2% and 0.9 g/dL (P < 0.001), respectively. In those men in the top quartile of changes in hematocrit (range of 6% to 14%), the largest increases in ambulatory SBP (mean, 8.3 mmHg) were observed, whereas the changes in ambulatory SBP in the lower 3 quartiles were smaller (mean, 1.9, 3.3, and 2.1 mmHg in 1st, 2nd and 3 rd quartiles, respectively).

CONCLUSION

These data demonstrate that small increases in ABP occurred following 4 months of the oral TU. For those men whose hematocrit rose by >6%, BP increases were of greater clinical relevance. Hence, hematocrit may aid in predicting the development of BP increases on testosterone therapy.

CLINICALTRIALS.GOV IDENTIFIER

NCT03868059.

Comparative transcriptome analysis reveals ectopic delta-5 and delta-6 desaturases enhance protective gene expression upon Vibrio vulnificus challenge in Tilapia (Oreochromis niloticus)

Background

Tilapia (Oreochromis niloticus) cultures are frequently infected by Vibrio vulnificus, causing major economic losses to production units. Previously, tilapia expressing recombinant delta-5 desaturase and delta-6 desaturase (D56) were found to be resistant to V. vulnificus infection. In this report, we profile the D56-mediated molecular changes underlying this resistance in tilapia. A comparative transcriptome analysis was performed on V. vulnificus-infected wild-type and D56-transgenic tilapia using Illumina’s sequencing-by-synthesis approach. Gene enrichment analysis on differentially expressed unigenes was performed, and the expression patterns were validated by real-time PCR.

Results

Comparative transcriptome analysis was performed on RNA-sequence profiles obtained from wild-type and D56-transgenic tilapia at 0, 6 and 24 h post-infection with V. vulnificaus. GO and KEGG gene enrichment analyses showed that D56 regulates several pathways and genes, including fatty acid (FA) metabolism associated, and inflammatory and immune response. Expression of selected FA metabolism-associated, inflammatory and immune responsive genes was validated by qPCR. The inflammatory and immune responsive genes that are modulated by FA-associated D56 likely contribute to the enhanced resistance against V. vulnificus infection in Tilapia.

Conclusions

Transcriptome profiling and filtering for two-fold change variation showed that 3795 genes were upregulated and 1839 genes were downregulated in D56-transgenic tilapia. These genes were grouped into pathways, such as FA metabolism, FA elongation, FA biosynthesis, biosynthesis of unsaturated FA, FA degradation, inflammation, immune response, and chemokines. FA-associated genes and immune-related genes were modulated by D56 at 6 h and 24 h post infection with V. vulnificus. The expression patterns of FA-related genes, inflammatory genes, antimicrobial peptide genes and immune responsive genes at 0, 3, 6, 12, 24 and 48 h post-infection suggests these genes are involved in the enhanced resistance of D56 transgenic tilapia to V. vulnificus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07521-5.

Approach to Interpreting Common Laboratory Pathology Tests in Transgender Individuals

CONTEXT

As the number of transgender (trans) people (including those who are binary and/or nonbinary identified) seeking gender-affirming hormone therapy rises, endocrinologists are increasingly asked to assist with interpretation of laboratory tests. Many common laboratory tests such as hemoglobin, iron studies, cardiac troponin, and creatinine are affected by sex steroids or body size. We seek to provide a summary of the impact of feminizing and masculinizing hormone therapy on common laboratory tests and an approach to interpretation.

CASES

Case scenarios discussed include 1) hemoglobin and hematocrit in a nonbinary person undergoing masculinizing hormone therapy; 2) estimation of glomerular filtration rate in a trans woman at risk of contrast-induced nephropathy; 3) prostate-specific antigen (PSA) in a trans woman; and 4) chest pain in a trans man with a cardiac troponin concentration between the reported male and female reference ranges.

CONCLUSIONS

The influence of exogenous gender-affirming hormone therapy on fat and muscle distribution and other physiological changes determines interpretation of laboratory tests that have sex-specific differences. In addition to affirmative practice to ensure a patient's name, gender, and pronoun are used appropriately, we propose that once individuals have commenced gender-affirming hormone therapy, the reference range of the affirmed gender be reported (and specified by treating clinicians) except for PSA or cardiac troponin, which are dependent on organ size. While suggestions may be challenging to implement, they also represent an opportunity to lead best practice to improve the quality of care and experiences of healthcare for all trans people.

Approach to Interpreting Common Laboratory Pathology Tests in Transgender Individuals

CONTEXT

As the number of transgender (trans) people (including those who are binary and/or nonbinary identified) seeking gender-affirming hormone therapy rises, endocrinologists are increasingly asked to assist with interpretation of laboratory tests. Many common laboratory tests such as hemoglobin, iron studies, cardiac troponin, and creatinine are affected by sex steroids or body size. We seek to provide a summary of the impact of feminizing and masculinizing hormone therapy on common laboratory tests and an approach to interpretation.

CASES

Case scenarios discussed include 1) hemoglobin and hematocrit in a nonbinary person undergoing masculinizing hormone therapy; 2) estimation of glomerular filtration rate in a trans woman at risk of contrast-induced nephropathy; 3) prostate-specific antigen (PSA) in a trans woman; and 4) chest pain in a trans man with a cardiac troponin concentration between the reported male and female reference ranges.

CONCLUSIONS

The influence of exogenous gender-affirming hormone therapy on fat and muscle distribution and other physiological changes determines interpretation of laboratory tests that have sex-specific differences. In addition to affirmative practice to ensure a patient's name, gender, and pronoun are used appropriately, we propose that once individuals have commenced gender-affirming hormone therapy, the reference range of the affirmed gender be reported (and specified by treating clinicians) except for PSA or cardiac troponin, which are dependent on organ size. While suggestions may be challenging to implement, they also represent an opportunity to lead best practice to improve the quality of care and experiences of healthcare for all trans people.

Mechanisms underlying the metabolic actions of testosterone in humans: A narrative review

The role of testosterone in improving sexual symptoms in men with hypogonadism is well known. However, recent studies indicate that testosterone plays an important role in several metabolic functions in males. Multiple PubMed searches were conducted with the use of the terms testosterone, insulin sensitivity, obesity, type 2 diabetes, anaemia, bone density, osteoporosis, fat mass, lean mass and body composition. This narrative review is focused on detailing the mechanisms that underlie the metabolic aspects of testosterone therapy in humans. Testosterone enhances insulin sensitivity in obese men with hypogonadism by decreasing fat mass, increasing lean mass, decreasing free fatty acids and suppressing inflammation. At a cellular level, testosterone increases the expression of insulin receptor β subunit, insulin receptor substrate-1, protein kinase B and glucose transporter type 4 in adipose tissue and adenosine 5'-monophosphate-activated protein kinase expression and activity in skeletal muscle. Observational studies show that long-term therapy with testosterone prevents progression from prediabetes to diabetes and improves HbA1c. Testosterone increases skeletal muscle satellite cell activator, fibroblast growth factor-2 and decreases expression of the muscle growth suppressors, myostatin and myogenic regulatory factor 4. Testosterone increases haematocrit by suppressing hepcidin and increasing expression of ferroportin along with that of transferrin receptor and plasma transferrin concentrations. Testosterone also increases serum osteocalcin concentrations, which may account for its anabolic actions on bone. In conclusion, testosterone exerts a series of potent metabolic effects, which include insulin sensitization, maintenance and growth of the skeletal muscle, suppression of adipose tissue growth and maintenance of erythropoiesis and haematocrit.

Markers of Iron Flux during Testosterone-Mediated Erythropoiesis in Older Men with Unexplained or Iron-Deficiency Anemia

CONTEXT

Testosterone treatment of hypogonadal men improves their hemoglobin, but the mechanism is not understood.

OBJECTIVE

To investigate possible mechanisms by which testosterone stimulates erythropoiesis in hypogonadal older men with unexplained or iron-deficiency anemia.

DESIGN

The Anemia Trial of The Testosterone Trials, a placebo-controlled study in older, hypogonadal men.

SETTING

Twelve academic medical centers.

PARTICIPANTS

A total of 95 hypogonadal men (testosterone < 275 ng/mL) ≥65 years with anemia (hemoglobin < 12.7 g/dL). They were classified as having unexplained (n = 58) or iron deficiency anemia (n = 37).

INTERVENTION

Testosterone or placebo gel for 1 year.

MAIN OUTCOME MEASURES

Markers of iron metabolism during the first 3 months of treatment.

RESULTS

Testosterone replacement significantly (P < 0.001) increased hemoglobin in the 58 men who had unexplained anemia (adjusted mean difference 0.58 g/dL; 95% confidence interval, 0.31-0.85). Testosterone replacement tended to increase hemoglobin in the 37 men who had iron deficiency (0.38 g/dL; -0.19, 0.95), but the response was more variable and not statistically significant (P = 0.19). In men with unexplained anemia, testosterone replacement suppressed hepcidin (-8.2 ng/mL; -13.7, -2.7; P = 0.004) and ferritin (-19.6 µg/L; -32.8, -6.3; P = 0.004), but in men with iron deficiency, testosterone replacement did not. The decrease in hepcidin was moderately correlated with the increase in hemoglobin in the men with unexplained anemia (correlation coefficient -0.35, P = 0.01) but not in those with iron deficiency anemia (correlation coefficient -0.07, P = 0.73).

CONCLUSIONS

Testosterone replacement of older hypogonadal men with unexplained anemia stimulates erythropoiesis associated with increased iron mobilization. This effect appears to be attenuated by iron deficiency.

Age-Related Changes and Sex-Related Differences in Brain Iron Metabolism

Iron is an essential element that participates in numerous cellular processes. Any disruption of iron homeostasis leads to either iron deficiency or iron overload, which can be detrimental for humans' health, especially in elderly. Each of these changes contributes to the faster development of many neurological disorders or stimulates progression of already present diseases. Age-related cellular and molecular alterations in iron metabolism can also lead to iron dyshomeostasis and deposition. Iron deposits can contribute to the development of inflammation, abnormal protein aggregation, and degeneration in the central nervous system (CNS), leading to the progressive decline in cognitive processes, contributing to pathophysiology of stroke and dysfunctions of body metabolism. Besides, since iron plays an important role in both neuroprotection and neurodegeneration, dietary iron homeostasis should be considered with caution. Recently, there has been increased interest in sex-related differences in iron metabolism and iron homeostasis. These differences have not yet been fully elucidated. In this review we will discuss the latest discoveries in iron metabolism, age-related changes, along with the sex differences in iron content in serum and brain, within the healthy aging population and in neurological disorders such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, and stroke.

Repeated hormonal induction of spermiation affects the stress but not the immune response in pikeperch (Sander lucioperca)

Hormonal induction of spermiation, previously reported to be immunogenic in fishes, is a common hatchery practice in pikeperch, Sander lucioperca. The aim of the present study was to investigate the effects of repeated induction of spermiation in pikeperch, following application of either human chorionic gonadotropin (hCG) or salmon gonadoliberine analogue (sGnRHa) on sperm quality indices as well as on immune and stress response. Mature males of pikeperch (n = 7 per group) were stimulated twice with five days between injections of either hCG (hCG; 500 IU kg^-1), sGnRHa (sGnRHa; 50 μg kg^-1) or NaCl (control group; 1 ml kg^-1) to assess spermatozoa motility with a computer-assisted sperm analysis (CASA) system. During second sampling, blood plasma was sampled for humoral innate immune (peroxidase and lysozyme activities, ACH50), stress (cortisol, glucose) and endocrine (testosterone) markers. In addition, the head kidney was dissected to assay the expression of several immune genes (such as il1, c3, hamp, tnf-α and lys genes). The results indicate that hormonal treatment significantly increased sperm production. Sperm sampled after the hormonal treatment maintained its quality throughout the study, regardless of the sampling time. However, it appears that the application of hCG induced elevated cortisol and glucose plasma levels compared to the control group. Almost all immune markers, except the relative expression of hepcidin (hamp gene), were unaffected by the two hormones applied. The results showed that the induction treatment of spermiation processes in pikeperch resulted in an important physiological stress response for which the intensity varied according to the hormonal agent used. However, this stress response (more profound following application of hCG) was weakly associated with innate immune functions. On the other hand, a significant negative correlation between the expression of several important immune markers (peroxidase activity, relative expression of c3 and il1 genes) and sperm quality indices indicates significant involvement of immune status on sperm quality. The results obtained shed light on immune-system-induced modifications to sperm quality. The data presented here highlight the need for careful revision of broodstock management and selection practices where welfare status as well as individual predispositions of fish to cope with the stress should be taken under the consideration.

Dapagliflozin Suppresses Hepcidin And Increases Erythropoiesis

CONTEXT

Dapagliflozin and other SGLT2 inhibitors are known to increase hematocrit, possibly due to its diuretic effects and hemoconcentration.

OBJECTIVE

Since type 2 diabetes is a proinflammatory state and since hepcidin, a known suppressor of erythropoiesis, is increased in proinflammatory states, we investigated the possibility that dapagliflozin suppresses hepcidin concentrations and thus increases erythropoiesis.

DESIGN

Prospective, randomized, and placebo-controlled study.

SETTING

Single endocrinology center.

PATIENTS

Fifty-two obese type 2 diabetes patients.

INTERVENTION

Patients were randomized (1:1) to either dapagliflozin (10 mg daily) or placebo for 12 weeks. Blood samples were collected before and after treatments and serum, plasma, and mononuclear cells (MNC) were prepared.

MAIN OUTCOME MEASURE

Hepcidin and other hematopoietic factors.

RESULTS

Following dapagliflozin treatment, there was a significant fall in HbA1c and a significant increase in hemoglobin concentration and hematocrit. Dapagliflozin treatment significantly reduced circulating hepcidin and ferritin concentrations while causing a significant increase in levels of the hepcidin inhibitor, erythroferrone, and a transient increase in erythropoietin. Additionally, dapagliflozin increased plasma transferrin levels and expression of transferrin receptors 1 and 2 in MNC, while there was no change in the expression of the iron cellular transporter, ferroportin. Dapagliflozin treatment also caused a decrease in hypoxia-induced factor-1α expression in MNC while it increased the expression of its inhibitor, prolyl hydroxylase-2. There were no significant changes in any of these indices in the placebo group.

CONCLUSIONS

We conclude that dapagliflozin increases erythropoiesis and hematocrit through mechanisms that involve the suppression of hepcidin and the modulation of other iron regulatory proteins.

Prevalence of Iron deficiency in Lebanese schoolchildren

BACKGROUND

The prevalence of iron deficiency in the Lebanese pediatric population is unknown. The aim of this study is to estimate this prevalence in Lebanese schoolchildren and to assess the relation between iron status and related factors.

SUBJECTS/METHODS

A total of 903 children aged 8-18 years (466 boys and 437 girls) were included in the study. Recruitment was done from ten schools with different SES levels and located in the Great Beirut and Mount Lebanon areas. Serum ferritin was measured in all participants and testosterone was measured only in boys using Immulite chemiluminescent assays.

RESULTS

For the entire sample, the median serum ferritin concentration was 30.0 [19.8-44.8] ng/mL and the prevalence of iron deficiency (ferritin < 15 ng/mL) was 14.2%. Iron deficiency was higher in girls compared with boys (respectively, 20.8% and 7.9%). This prevalence varied with the SES (respectively, 11.6%, 11.9%, and 16.8% in high, middle, and low SES, p = 0.09). Iron deficiency increased with age (9.5%, 15.7%, and 17.5%, respectively, for the age groups 8-11, 12-14, and 15-18, p = 0.014) and did not differ between normal, overweight, and obese groups (p = 0.07). In boys, a significant positive correlation was observed between ferritin and total testosterone (rho = 0.150, p = 0.001).

CONCLUSION

The prevalence of iron deficiency is relatively low in Lebanon. Younger boys, menstruating girls, and children from low SES are more prone to iron deficiency, while BMI has no impact.

Alteration in iron efflux affects male sex hormone testosterone biosynthesis in a diet-induced obese rat model

This study was motivated by clinical observations that dysmetabolic iron overload syndrome (DIOS) and an androgen deficiency are common features observed in obese adult men; however, the molecular mechanism underlying the effects of DIOS on androgen deficiency remains to be elucidated. We established a DIOS animal model by feeding Sprague-Dawley rats an iron/fat-enriched diet (50% fat plus 0.25, 1, or 2 g ferric iron per kg diet) for 12 weeks to induce iron dysfunction (indicated by decreased tissue iron efflux) in obese rats. Obese rats fed an iron/fat-enriched diet showed decreased levels of testicular total Testosterone (T) and iron exporter ferroportin but increased levels of testicular iron and hepcidin, and these effects were more evident with a >1 g ferric iron per kg diet. A western blot analysis showed that an iron/fat-enriched diet triggered testicular endoplasmic reticular (ER) stress but decreased mitochondrion biogenesis proteins (PGC1α and TFAM) and T-converting proteins (StAR, CYP11A, and 17β-HSD). TUNEL staining showed that >1 g ferric iron induced apoptosis mainly in germ cells and Leydig's cells. Uncontrolled testicular iron efflux may cause mitochondrial-ER dysfunction and affect T biosynthesis. Future study targeting the testicular hepcidin-ferroportin axis may offer a therapeutic tool to alleviate testicular iron retention and mitochondrial-ER stress in Leydig's cells.

Androgen Therapy in Male Patients Suffering from Type 2 Diabetes: A Review of Benefits and Risks

BACKGROUND

The current estimated numbers of patients with Type 2 Diabetes (T2D) is believed to be close to 10% of the whole populations of many geographical regions, causing serious concerns over the resulting elevated morbidity and mortality as well as the impact on health care systems around the world. In addition to negatively affecting the quality of life, diabetes is associated with cardiovascular and cerebrovascular complications, indicating that appropriate drug therapy should not only deal with metabolic dysfunction but also protect the vascular system, kidney function and skeletal muscle mass from the effects of the epigenetic changes induced by hyperglycaemia.

OBJECTIVE

To provide an insight into the management of hypogonadism associated with T2D, this review focuses on clinical observations related to androgen therapy in qualified diabetic patients, and discusses the lines of evidence for its benefits and risks. The potential interactions of testosterone with medicines used by patients with T2D will also be discussed.

CONCLUSION

From recent clinical findings, it became evident that a considerable percentage of patients suffering from T2D manifested low serum testosterone and experienced diminished sexual activity, as well as reduced skeletal muscle mass and lower bone density. Although there are some controversies, Testosterone Replacement Therapy (TRT) for this particular population of patients appears to be beneficial overall only if it is implemented carefully and monitored regularly.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Hepcidin Therapeutics

Hepcidin is a key hormonal regulator of systemic iron homeostasis and its expression is induced by iron or inflammatory stimuli. Genetic defects in iron signaling to hepcidin lead to “hepcidinopathies” ranging from hereditary hemochromatosis to iron-refractory iron deficiency anemia, which are disorders caused by hepcidin deficiency or excess, respectively. Moreover, dysregulation of hepcidin is a pathogenic cofactor in iron-loading anemias with ineffective erythropoiesis and in anemia of inflammation. Experiments with preclinical animal models provided evidence that restoration of appropriate hepcidin levels can be used for the treatment of these conditions. This fueled the rapidly growing field of hepcidin therapeutics. Several hepcidin agonists and antagonists, as well as inducers and inhibitors of hepcidin expression have been identified to date. Some of them were further developed and are currently being evaluated in clinical trials. This review summarizes the state of the art.

Hypogonadotropic Hypogonadism in Men With Diabesity

One-third of men with obesity or type 2 diabetes have subnormal free testosterone concentrations. The lower free testosterone concentrations are observed in obese men at all ages, including adolescents at completion of puberty. The gonadotropin concentrations in these males are inappropriately normal; thus, these patients have hypogonadotropic hypogonadism (HH). The causative mechanism of diabesity-induced HH is yet to be defined but is likely multifactorial. Decreased insulin and leptin signaling in the central nervous system are probably significant contributors. Contrary to popular belief, estrogen concentrations are lower in men with HH. Men with diabesity and HH have more fat mass and are more insulin resistant than eugonadal men. In addition, they have a high prevalence of anemia and higher mortality rates than eugonadal men. Testosterone replacement therapy results in a loss of fat mass, gain in lean mass, and increase in insulin sensitivity in men with diabesity and HH. This is accompanied by an increase in insulin-signaling genes in adipose tissue and a reduction in inflammatory mediators that interfere with insulin signaling. There is also an improvement in sexual symptoms, anemia, LDL cholesterol, and lipoprotein (a). However, testosterone therapy does not consistently affect HbA_1c in men with diabetes. The effect of testosterone replacement on cardiovascular events or mortality in men with diabesity is not known and remains to be studied in prospective trials.

Deletion of ferroportin in murine myeloid cells increases iron accumulation and stimulates osteoclastogenesis in vitro and in vivo

Osteoporosis, osteopenia, and pathological bone fractures are frequent complications of iron-overload conditions such as hereditary hemochromatosis, thalassemia, and sickle cell disease. Moreover, animal models of iron overload have revealed increased bone resorption and decreased bone formation. Although systemic iron overload affects multiple organs and tissues, leading to significant changes on bone modeling and remodeling, the cell autonomous effects of excessive iron on bone cells remain unknown. Here, to elucidate the role of cellular iron homeostasis in osteoclasts, we generated two mouse strains in which solute carrier family 40 member 1 (Slc40a1), a gene encoding ferroportin (FPN), the sole iron exporter in mammalian cells, was specifically deleted in myeloid osteoclast precursors or mature cells. The FPN deletion mildly increased iron levels in both precursor and mature osteoclasts, and its loss in precursors, but not in mature cells, increased osteoclastogenesis and decreased bone mass in vivo Of note, these phenotypes were more pronounced in female than in male mice. In vitro studies revealed that the elevated intracellular iron promoted macrophage proliferation and amplified expression of nuclear factor of activated T cells 1 (Nfatc1) and PPARG coactivator 1β (Pgc-1β), two transcription factors critical for osteoclast differentiation. However, the iron excess did not affect osteoclast survival. While increased iron stimulated global mitochondrial metabolism in osteoclast precursors, it had little influence on mitochondrial mass and reactive oxygen species production. These results indicate that FPN-regulated intracellular iron levels are critical for mitochondrial metabolism, osteoclastogenesis, and skeletal homeostasis in mice.

Sex hormone-binding globulin is associated with androgen deficiency features independently of total testosterone

OBJECTIVE

It is recognized that total testosterone (TT) does not sufficiently describe androgen status when sex hormone-binding globulin (SHBG) is altered. However, in humans, evidence supporting the existence of a hypogonadism due to low T bioactivity is scanty. The aim of the study was to assess whether changes in SHBG levels, independently of TT, are associated with subjective and objective androgen-dependent parameters.

DESIGN

Cross-sectional observation.

PATIENTS

Two thousand six hundred and twenty-two men (aged 51.1 ± 13.5 years) attending a Sexual Medicine and Andrology Outpatient Clinic for sexual dysfunctions.

MEASUREMENTS

All patients underwent a standardized diagnostic protocol before starting any treatment. Clinical and biochemical parameters have been collected. Higher ANDROTEST score has been used as a comprehensive marker of more severe hypogonadal symptoms. Prostate-specific antigen (PSA) and haematocrit have been used as objective surrogate markers of T bioactivity.

RESULTS

After adjusting for TT and lifestyle, SHBG showed a significant positive association with ANDROTEST score (B = 0.79 [0.61; 0.96], P < .0001). Conversely, higher SHBG, independently of TT, was negatively related to PSA (B = -0.86 [-0.83; -0.89]; P < .0001) and haematocrit (B = -0.64 [-0.88; -0.40]; P < .0001), after adjustment for the aforementioned confounders along with age and body mass index. Furthermore, a relationship between SHBG and lipids or blood pressure was found, with lower SHBG levels associated with a worse metabolic profile, independently of TT.

CONCLUSIONS

Higher SHBG, independently of TT, is associated with either subjective or objective androgen deficiency features. This indicates that besides a hypogonadism due to an impaired T production, a hypogonadism due to a lower biological activity of T does exist.

A Case of Male Osteoporosis: A 37-Year-Old Man with Multiple Vertebral Compression Fractures

While the contributing role of testosterone to bone health is rather modest compared to other factors such as estradiol levels, male hypogonadism is associated with low bone mass and fragility fractures. Along with stimulating physical puberty by achieving virilization and a normal muscle mass and improving psychosocial wellbeing, the goals of testosterone replacement therapy in male hypogonadism also include attainment of age-specific bone mineral density. We report on a 37-year-old man who presented with multiple vertebral compression fractures several years following termination of testosterone replacement therapy for presumed constitutional delay in growth and puberty. Here, we discuss the management of congenital hypogonadotropic hypogonadism with hyposmia (Kallmann syndrome), with which the patient was ultimately diagnosed, the role of androgens in the acquisition of bone mass during puberty and its maintenance thereafter, and outline specific management strategies for patients with hypogonadism and high risk for fragility fractures.