Altered bone status in unilateral testicular cancer survivors: Role of CYP2R1 and its luteinizing hormone-dependency

Prognostic role of plasma vitamin D and its association with disease characteristics in germ cell tumours

Background

Testicular cancer is the most common malignancy among young men. Vitamin D has pluripotent effects on cancer pathogenesis and plays a role in the metastatic cascade. The aim of this study is to analyze plasma vitamin D in association with clinico-pathological findings and prognosis in patients with germ-cell tumors (GCTs).

Methods

This study included 120 newly diagnosed and/or relapsed GCT patients treated from April 2013 to July 2020, for whom plasma was available in the biobank. Blood samples were drawn the 1st chemotherapy cycle as well as before the 2nd cycle. Plasma vitamin D was measured using ELISA and correlated with disease characteristics and the outcome. For survival analysis, the cohort was dichotomized into "low" and "high" based on median vitamin D.

Results

There was no significant difference in vitamin D plasma levels between healthy donors and GCT patients (p = 0.71). Vitamin D level was not associated with disease characteristics except for brain metastases, where patients with brain metastases had a vitamin D level that was 32% lower compared to patients without brain metastases, p = 0.03. Vitamin D was also associated with response to chemotherapy, with an approximately 32% lower value in patients with an unfavorable response compared to a favorable response, p = 0.02. Moreover, low plasma levels of vitamin D were significantly associated with disease recurrence and inferior progression-free survival (PFS), but not with overall survival (OS) (HR = 3.02, 95% CI 1.36-6.71, p = 0.01 for PFS and HR = 2.06, 95% CI 0.84-5.06, p = 0.14 for OS, respectively).

Conclusion

Our study suggests the prognostic value of pretreatment vitamin D concentrations in GCT patients. Low plasma vitamin D was associated with an unfavorable response to therapy and disease recurrence. However, it remains to be determined whether the biology of the disease confirms a causative role for low vitamin D and whether its supplementation affects the outcome.

Risk of osteoporosis in testicular germ cell tumour survivors: A systematic review of the literature

Context

Testicular germ cell tumour (TGCT) survivors are potentially at risk of developing osteoporosis, because of increased risk for disturbed bone remodelling associated with hypogonadism and anti-cancer treatment. A number of studies show bone loss and increased fracture risk in TGCT survivors, but data are scarce. There are no clinical guidelines or recommendations issued to address skeletal health in this group of patients potentially at high risk for osteoporosis.

Objective

To conduct a systematic review of available literature addressing bone health in TGCT patients. Subgroup analysis was performed to identify risk factors for bone loss and increased fracture risk.

Evidence Acquisition

Relevant databases, including MEDLINE, Embase and the Cochrane Library, including all English written comparative studies addressing bone health in TGCT patients, were searched up to December 2021 and a narrative synthesis was undertaken. Risk of bias (RoB) was assessed using Cochrane ROBINS-I tool.

Evidence Synthesis

Ten studies (eight cross-sectional and two longitudinal), recruiting a total of 1997 unique TGCT patients, were identified and included in the analysis. Bone health was reported in various ways in different studies, and subgroups were defined heterogeneously, resulting in a widely varying prevalence of osteoporosis of up to 73.2% of patients. Six studies reported low BMD associated with higher luteinizing hormone levels and one study showed a correlation between follow up duration and bone loss.

Conclusions

TGCT survivors are at risk of developing osteoporosis and sustaining fragility fractures. Chemotherapy, pituitary-gonadal axis dysfunction and ageing are key risk factors, although available data are scarce. With increasing survival of TGCT patients, a clear unmet need has been identified to systematically evaluate and monitor skeletal health in larger numbers of survivors in order to develop best clinical practice guidelines to manage the insidious but potentially preventable and treatable skeletal complications of TGCT.

Functional hypogonadism among patients with obesity, diabetes, and metabolic syndrome

Testosterone deficiency, defined as low total testosterone combined with physical, cognitive, and sexual signs and/or symptoms, is a common finding in adult men. Functional hypogonadism (FH) is defined as borderline low testosterone (T) secondary to aging and/or comorbid conditions such as diabetes, obesity, and/or metabolic syndrome. The relationship between FH and metabolic disorders is multifactorial and bidirectional, and associated with a disruption of the hypothalamic-pituitary-gonadal axis. Resolution of FH requires the correct diagnosis and treatment of the underlying condition(s) with lifestyle modifications considered first-line therapy. Normalization of T levels through dietary modifications such as caloric restriction and restructuring of macronutrients have recently been explored. Exercise and sleep quality have been associated with T levels, and patients should be encouraged to practice resistance training and sleep seven to nine hours per night. Supplementation with vitamin D and Trigonella foenum-graecum may also be considered when optimizing T levels. Ultimately, treatment of FH requires a multidisciplinary approach and personalized patient care.

Vitamin D Deficiency in Testicular Cancer Survivors: A Systematic Review

Testicular cancer (TC) is the most frequent tumor in young males. In the vast majority of cases, it is a curable disease; therefore, very often patients experience a long survival, also due to their young age at diagnosis. In the last decades, the role of the vitamin D deficiency related to orchiectomy has become an increasingly debated topic. Indeed, vitamin D is essential in bone metabolism and many other metabolic pathways, so its deficiency could lead to various metabolic disorders especially in long-term TC survivors. In our article, we report data from studies that evaluated the incidence of hypovitaminosis D in TC survivors compared with cohorts of healthy peers and we discuss molecular mechanisms and clinical implications.

Serum 25OHD3 of Obese Mice Is Affected by Liver Injury and Correlates with Testosterone Levels and Sperm Motility

INTRODUCTION

The concentration of 25-hydroxycholecalciferol (25OHD3) in the serum of obese people is low and often accompanied by symptoms of low fertility. Therefore, vitamin D is recommended as a potential treatment option. However, after clinical trials, it was found that vitamin D cannot effectively increase the concentration of 25OHD3 in the serum of obese people. How obesity causes low 25OHD3 concentration and low fertility is unclear.

METHODS

We analyzed the physiological and pathological changes in obese mice induced by a high-fat diet (HFD) and the changes in mice after supplementing with 25OHD3.

RESULTS

The concentration of 25OHD3 in the serum of obese mice induced by HFD was significantly reduced, and these mice showed liver hypertrophy accompanied by abnormal liver injury, testicular hypertrophy, low testosterone levels, high leptin levels, and low sperm motility. The mRNA and protein expression of CYP2R1 of hydroxylated vitamin D3 was significantly reduced; CYP11A1 and CYP11A2, which synthesize testosterone, were significantly reduced. After supplementing with 25OHD3, there was an increase in serum 25OHD3 concentration, testosterone level, and sperm motility, but it cannot improve the degree of obesity, CYP2R1 expression, and liver damage.

CONCLUSION

Our research shows that there is a metabolic interference mediated by 25OHD3 and testosterone between obesity and low sperm motility. The results of this study can provide a scientific basis for studying the mechanism of 25OHD3 and hormone regulation and treating obese people with low sperm motility.

Obesity Represses CYP2R1, the Vitamin D 25-Hydroxylase, in the Liver and Extrahepatic Tissues

Low plasma level of 25-hydroxyvitamin D (25-OH-D), namely vitamin D deficiency, is associated with obesity and weight loss improves 25-OH-D status. However, the mechanism behind obesity-induced vitamin D deficiency remains unclear. Here, we report that obesity suppresses the expression of cytochrome P450 (CYP) 2R1, the main vitamin D 25-hydroxylase, in both mice and humans. In humans, weight loss induced by gastric bypass surgery increased the expression of CYP2R1 in the s.c. adipose tissue suggesting recovery after the obesity-induced suppression. At the same time, CYP27B1, the vitamin D 1α-hydroxylase, was repressed by the weight loss. In a mouse (C57BL/6N) model of diet-induced obesity, the plasma 25-OH-D was decreased. In accordance, the CYP2R1 expression was strongly repressed in the liver. Moreover, obesity repressed the expression of CYP2R1 in several extrahepatic tissues, the kidney, brown adipose tissue, and testis, but not in the white adipose tissue. Obesity had a similar effect in both male and female mice. In mice, obesity repressed expression of the vitamin D receptor in brown adipose tissue. Obesity also upregulated the expression of the vitamin D receptor and CYP24A1 in the s.c. adipose tissue of a subset of mice; however, no effect was observed in the human s.c. adipose tissue. In summary, we show that obesity affects CYP2R1 expression both in the mouse and human tissues. We suggest that in mouse the CYP2R1 repression in the liver plays an important role in obesity-induced vitamin D deficiency. Currently, it is unclear whether the CYP2R1 downregulation in extrahepatic tissues could contribute to the obesity-induced low plasma 25-OH-D, however, this phenomenon may affect at least the local 25-OH-D concentrations. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Fertility Outcomes and Sperm-DNA Parameters in Metastatic Melanoma Survivors Receiving Vemurafenib or Dabrafenib Therapy: Case Report

Melanoma is a frequent neoplasm in young adult males in reproductive age, 10% of them degenerating into regional and/or distant metastases (MM). The use of BRAF inhibitors (BRAFi) vemurafenib and dabrafenib is effective in MM patients harboring BRAF V600E/K/D mutations. Despite the increased life expectancy in MM patients treated with BRAFi, concerns are raised by the possible side effects and increased risk of gonado- and/or genotoxicity associated with these drugs. However, these aspects are currently under-investigated. Here we report the different fertility outcome in two cases of MM patients, harboring BRAF V600E mutation, that received vemurafenib and dabrafenib respectively. The first patient, 36 years at recruitment in 2015 and seeking fatherhood, had an history of relapsing melanoma since 2002 and undergone to numerous interventions and chemotherapy cycles. In November 2011, following detection of BRAF V600E mutation, a daily treatment with vemurafenib (1,440 mg) was prescribed with preventive gamete cryopreservation. BRAFi was effective in the clinical stabilization of the disease. In 2015, semen evaluation at follow-up showed sperm parameters within the normal range and no signs of alteration of either sperm function or sperm-DNA. On these bases, no contraindications for fatherhood were given. After a month of free intercourses, the 38-year-old partner achieved spontaneous pregnancy with a regular course, normal male fetal karyotype and a full term birth. The second patient, 39 years at recruitment in 2018 and seeking fatherhood, had an history of melanoma since 2012. In 2018, following the evidence of disease relapse and detection of the BRAF V600E mutation, treatment with dabrafenib/trametinib (300 mg/day/2 mg/day) was initiated together with preventive gamete cryopreservation. In 2019, semen evaluation at follow up showed sperm count and motility below the reference values, associated with increased indexes of sperm aneuploidies and sperm DNA fragmentation. Accordingly, access to assisted reproduction technique with cryopreserved spermatozoa was suggested. Differently from dabrafenib that was associated to damage to spermatogenesis, high-dose vemurafenib showed no association with gonadotoxicity and genotoxicity in humans, even at high doses. Although further confirmation are required, our data represent a valued cue in oncofertility counseling to MM patients in addition to preventive cryopreservation.

Hypogonadism and Sexual Dysfunction in Testicular Tumor Survivors: A Systematic Review

Testicular tumor is the most common malignancy in men of reproductive age. According to the tumor histology and staging, current treatment options include orchiectomy alone or associated with adjuvant chemo- and/or radiotherapy. Although these treatments have considerably raised the percentage of survivors compared to the past, they have been identified as risk factors for testosterone deficiency and sexual dysfunction in this subgroup of men. Male hypogonadism, in turn, predisposes to the development of metabolic and cardiovascular impairment that negatively affects general health. Accordingly, longitudinal studies report a long-term risk for cardiovascular diseases after radiotherapy and/or cisplatin-based chemotherapy in testicular tumor survivors. The aim of this review was to summarize the current evidence on hypogonadism and sexual dysfunction in long-term cancer survivors, including the epidemiology of cardiovascular and metabolic disorders, to increase the awareness that serum testosterone levels, sexual function, and general health should be evaluated during the endocrinological management of these patients.

Investigating the effect of testosterone by itself and in combination with letrozole on 1,25-dihydroxy vitamin D and FGF23 in male rats

BACKGROUND

Testosterone deficiency might be associated with vitamin D levels in hypogonadal men, but it is not clear whether testosterone can affect vitamin D and fibroblast growth factor-23 (FGF23), either directly or indirectly via aromatization to estradiol. We aimed to investigate the role of testosterone on vitamin D metabolism and serum FGF23 in male rats.

METHODS

A total of 48 male rats were divided into 4 equal groups: sham; O, orchiectomy; O + T, orchiectomized rats treated with testosterone; and O + T + L, orchiectomized rats treated with combination of testosterone and letrozole. We compare the vitamin D metabolism biochemical parameters in these four groups, before and after the study.

RESULTS

We detected a significant reduction in 25-hydroxyvitamin D (25(OH)D), vitamin D binding protein (DBP), FGF23, and 1,25-dihydroxyvitamin D (1,25(OH)2D) serum level in O group compared to sham group (p = 0.004, p = 0.009, p < 0.001 and p < 0.001, respectively), and a significant increase in serum phosphorus, parathyroid hormone (PTH), and alkaline phosphatase (ALP) levels in orchiectomized rats in comparison to sham group (p < 0.001, p = 0.022, and p = 0.006, respectively). However, these changes were corrected by testosterone replacement in O + T and O + T + L groups. In addition, we found that DBP and 1,25(OH)2D serum levels were significantly higher in O + T group in comparison to O + T + L group (p = 0.030 and p = 0.026, respectively).

CONCLUSIONS

Testosterone plays a significant role on regulating 25(OH)D, DBP, FGF23, phosphate (Phos), PTH, and 1,25(OH)2D serum levels in male rats. Also, testosterone has a potent effect on 1,25(OH)2D and DBP by its conversion to estradiol.

Long term deficiency of vitamin D in germ cell testicular cancer survivors

Background

Cisplatin-based chemotherapy significantly improved the survival of patients with germ cell testicular cancer. However, long term side effects of chemotherapy have non-negligible impact on the quality of life of these young patients, who have a long life expectancy after being successfully treated.

Materials and Methods

25-OH vitamin D, testosterone, FSH and LH of patients with testicular cancer were retrospectively evaluated and for each patient clinical information were collected. The tissue of 52 patients with germ cell tumors was analyzed for VDR expression by immunohistochemistry. The serum 25-OH vitamin D and VDR expression were correlated to the patients 'clinical characteristics.

Results

25-OH vitamin D was analyzed in 82 patients. Insufficient (< 30 ng/ml) levels were detected in 65%-85%, mild deficient (< 20 ng/ml) in 25%-36% and severe deficient (< 10 ng/ml) in 6%-18% of the patients over a median follow-up of 48 months. No difference in serum 25-OH vitamin D was detected over the follow-up time points. No correlation with histology, stage and type of treatment was found. The 25-OH vitamin D levels were not correlated to testosterone, FSH and LH levels. Interestingly, the expression of VDR was much higher in non seminoma than in seminoma tissue.

Conclusions

Patients with testicular cancer have reduced vitamin D levels after the treatment of the primary cancer. Since long term hypovitaminosis D leads to high risk of fractures, infertility and cardiovascular diseases, we envision that vitamin D should be regularly checked in patients with testicular cancer and replaced if needed.

Vitamin D status among long-term survivors of testicular cancer

A correlation between disturbances in hormone levels and the onset of metabolic disorders has been reported in long-term survivors of testicular cancer (TC).

We evaluated serum vitamin D levels and other biological parameters in a consecutive series of 61 long-term (≥3 years) unilateral TC survivors with a median a follow-up of 4 years and in a cohort of healthy males. Deficient vitamin D levels were observed in 10 (17%) of the 58 long-term unilateral TC survivors but were not reported in healthy males (p=.019, Fisher test). Median vitamin D levels were 18.6 ug/L in 58 assessable TC survivors and 23.6 ug/L in 40 healthy males (p=.031). In univariate logistic regression analysis, TC diagnosis was associated with inadequate levels of vitamin D (p=.047). Vitamin D levels were lower when follow-up was > 10 years, albeit this difference was not statistically significant (p=.074). Long-term (especially > 10 years) TC survivors may have difficulty maintaining optimal vitamin D levels. Larger studies are needed to better characterize vitamin D status and possible correlations with premature hormonal aging reported in long-term TC survivors.

Vitamin D, PCOS and androgens in men: a systematic review

BACKGROUND

Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the reproductive system in both genders.

AIM

The aim of this review was to provide an overview on the effects of vitamin D on polycystic ovary syndrome (PCOS) in women and androgen metabolism in men.

METHODS

We performed a systematic literature search in PubMed for relevant English language publications published from January 2012 until September 2017.

RESULTS AND DISCUSSION

The vitamin D receptor and vitamin D-metabolizing enzymes are found in reproductive tissues of women and men. In women, vitamin D status has been associated with several features of PCOS. In detail, cross-sectional data suggest a regulatory role of vitamin D in PCOS-related aspects such as ovulatory dysfunction, insulin resistance as well as hyperandrogenism. Moreover, results from randomized controlled trials (RCTs) suggest that vitamin D supplementation may be beneficial for metabolic, endocrine and fertility aspects in PCOS. In men, vitamin D status has been associated with androgen levels and hypogonadism. Further, there is some evidence for a favorable effect of vitamin D supplementation on testosterone concentrations, although others failed to show a significant effect on testosterone levels.

CONCLUSION

In summary, vitamin D deficiency is associated with adverse fertility outcomes including PCOS and hypogonadism, but the evidence is insufficient to establish causality. High-quality RCTs are needed to further evaluate the effects of vitamin D supplementation in PCOS women as well as on androgen levels in men.

Increased risk of testis failure in testicular germ cell tumor survivors undergoing radiotherapy

Testicular germ cell tumors (TGCTs) are prevalent in males of reproductive age. Among the available therapeutic choices, pelvic radiotherapy (RT) and simple surveillance (SURV) are usually pursued. However, RT is considered to have life-threatening effects on testicular functions. In this study we sought to clarify this issue by evaluating sperm parameters and sex hormones in 131 TGCTs RT-treated-patients at both baseline (T0) and 12 (T1) and 24 months (T2) of follow-up. An age-matched group of 61 SURV patients served as control. Sperm parameters were comparable between SURV and RT at T0.

The RT group showed a significant reduction of all sperm parameters at T1 (all P values < 0.05 vs T0 and vs SURV at T1) and increased levels of sperm aneuploidies, with some degree of recovery at T2. On the other hand, despite normal levels of total testosterone being detected in both groups, luteinizing hormone (LH) levels in the RT group progressively increased at T1 and T2 with a relative risk of developing subclinical hypogonadism of 3.03 (95% CI: 1,50–6,11) compared to SURV. Again, compared to SURV, exposure to RT was associated with a 5.78 fold (95% CI: 2,91–11,48) risk of developing vitamin D insufficiency. These data suggest a likely RT-dependent impairment of the Leydig cell compartment.

The role of vitamin D in male fertility: A focus on the testis

In the last decade, vitamin D has emerged as a pleiotropic molecule with a multitude of autocrine, paracrine and endocrine functions, mediated by classical genomic as well as non-classical non-genomic actions, on multiple target organs and systems. The expression of vitamin D receptor and vitamin D metabolizing enzymes in male reproductive system, particularly in the testis, suggests the occurrence of vitamin D synthesis and regulation as well as function in the testis. The role of vitamin D in the modulation of testis functions, including hormone production and spermatogenesis, has been investigated in animals and humans. Experimental studies support a beneficial effect of vitamin D on male fertility, by modulating hormone production through genomic and non-genomic actions, and, particularly, by improving semen quality essentially through non-genomic actions. However, clinical studies in humans are controversial. Indeed, vitamin D seems to contribute to the modulation of the bioavailable rather than total testosterone. Moreover, although an increased prevalence or risk for testosterone deficiency was reported in men with vitamin D deficiency in observational studies, the majority of interventional studies demonstrated the lack of effect of vitamin D supplementation on circulating levels of testosterone. The most consistent effect of vitamin D was reported on semen quality. Indeed, vitamin D was shown to be positively associated to sperm motility, and to exert direct actions on spermatozoa, including non-genomic driven modulation of intracellular calcium homeostasis and activation of molecular pathways involved in sperm motility, capacitation and acrosome reaction. The current review provides a summary of current knowledge on the role of vitamin D in male fertility, by reporting clinical and experimental studies in humans and animals addressing the relationship between vitamin D and testis function.

Late-onset hypogonadism: beyond testosterone

Late-onset hypogonadism is defined as a combination of low testosterone (T) levels and typical symptoms and signs. A major area of uncertainty is whether T concentrations are always really sufficient to fully reflect Leydig cell (dys)function. Mild testicular alteration could be diagnosed only by additional biochemical markers, such as luteinizing hormone (LH) and 25-hydroxyvitamin D levels. These markers help in identifying the so-called “subclinical” hypogonadism (normal T, high LH levels). Patients with hypogonadism have frequently low levels of 25-hydroxyvitamin D due to impairment of the hydroxylating enzyme CYP2R1 in the testis. However, no data have been published dealing with the best treatment option (cholecalciferol – the Vitamin D precursor, or calcidiol - 25-hydroxylated form of Vitamin D) in these patients. We studied 66 patients with classic hypogonadism (total T [TT] <12 nmol l⁻¹, LH ≥ 8 IU l⁻¹) (n = 26) and subclinical hypogonadism (TT ≥ 12 nmol l⁻¹, LH ≥ 8 IU l⁻¹) (n = 40) and low 25-hydroxyvitamin D (<50 nmol l⁻¹). Subjects received cholecalciferol (5000 IU per week) (n = 20) or calcidiol (4000 IU per week) (n = 46), and 25-hydroxyvitamin D and parathyroid hormone (PTH) were evaluated after 3 months of therapy. Supplementation with calcidiol significantly increased 25-hydroxyvitamin D and significantly decreased PTH levels in both groups of men with hypogonadism (primary, n = 16 and subclinical, n = 30), whereas supplementation with cholecalciferol did not modify their levels. This study shows for the first time that the administration of the 25-hydroxylated form of Vitamin D (calcidiol), and not the administration of the precursor cholecalciferol, restores 25-hydroxyvitamin D levels in subjects with hypogonadism.

CYP2R1 is a major, but not exclusive, contributor to 25-hydroxyvitamin D production in vivo

Bioactivation of vitamin D consists of two sequential hydroxylation steps to produce 1α,25-dihydroxyvitamin D3. It is clear that the second or 1α-hydroxylation step is carried out by a single enzyme, 25-hydroxyvitamin D 1α-hydroxylase CYP27B1. However, it is not certain what enzyme or enzymes are responsible for the initial 25-hydroxylation. An excellent case has been made for vitamin D 25-hydroxylase CYP2R1, but this hypothesis has not yet been tested. We have now produced Cyp2r1 (-/-) mice. These mice had greater than 50% reduction in serum 25-hydroxyvitamin D3. Curiously, the 1α,25-dihydroxyvitamin D3 level in the serum remained unchanged. These mice presented no health issues. A double knockout of Cyp2r1 and Cyp27a1 maintained a similar circulating level of 25-hydroxyvitamin D3 and 1α,25-dihydroxyvitamin D3. Our results support the idea that the CYP2R1 is the major enzyme responsible for 25-hydroxylation of vitamin D, but clearly a second, as-yet unknown, enzyme is another contributor to this important step in vitamin D activation.