Background: Some evidence suggests that diabetes mellitus type 1 (DM1) could affect male fertility, gonadal axis, semen parameters, and spermatogenesis because of effects of hyperglycemia and insulin deficiency. Anyhow, the exact impact of DM1 on male fertility is unclear. Objectives:To review the studies evaluating paternity rate, male gonadal axis, and semen parameters in men with DM1. Materials and methods:A review of relevant literature from January 1980 to December 2020 was performed. Only studies published in English reporting data on fatherhood (rate of children by natural fertility), hormonal and seminal parameters were included. Out of 14 retrieved articles, the eight studies evaluating semen parameters were meta-analyzed. Results:The rate of children (four studies) was lower than controls among men affected by DM1, especially in men with a longer duration of disease. The data of gonadal hormonal profile in DM1 men (six studies) are very heterogeneous and a neutral effect of DM1 or a condition of subclinical hypogonadism could not be concluded.Meta-analysis showed that men with DM1 (n = 380), compared with controls (n = 434), have significantly lower normal sperm morphology [-0.36% (-0.66; -0.06), p < 0.05, six studies] and sperm progressive motility [33.62% (-39.13; -28.11), p < 0.001, two studies] and a trend toward a lower seminal volume [-0.51 (-1.03; 0.02), p = 0.06, eight studies], without difference in total sperm count and concentration. Data on scrotal ultrasound and sperm DNA fragmentation are too few. No study evaluated other factors of male infertility, such as transrectal ultrasound, semen infections, sperm autoantibodies, and retrograde ejaculation.Discussion: DM1 might impair male fertility and testis functions (endocrine, spermatogenesis), but definition of its actual impact needs further studies. Conclusion:Men with DM1 should be evaluated with a complete hormonal, seminal, and ultrasound workup to better define their fertility potential and need for follow up of testis functions.

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Male hypogonadism is defined as low circulating testosterone level associated with signs and symptoms of testosterone deficiency. Although the bidirectional link between hypogonadism and cardiovascular disease has been clarified, the association between testosterone and chronic heart failure (HF) is more controversial. Herein, we critically review published studies relating to testosterone, hypogonadism, and HF and provide practical clinical information on proper diagnosis and treatment of male hypogonadism in patients with HF. In general, published studies are extremely heterogeneous, frequently have not adhered to hypogonadism guidelines, and suffer from many intrinsic methodological inaccuracies; therefore, data provide only low-quality evidence. Nevertheless, by selecting the few methodologically robust studies, we show the prevalence of testosterone deficiency (30%–50%) and symptomatic hypogonadism (15%) in men with HF is significant. Low testosterone correlates with HF severity, New York Heart Association class, exercise functional capacity, and a worse clinical prognosis and mortality. Interventional studies on testosterone treatment in men with HF are inconclusive but do suggest beneficial effects on exercise capacity, New York Heart Association class, metabolic health, and cardiac prognosis. We suggest that clinicians should measure testosterone levels in men with HF who have symptoms of a testosterone deficiency and conditions that predispose to hypogonadism, such as obesity and diabetes. These patients—if diagnosed as hypogonadal—may benefit from the short- and long-term effects of testosterone replacement therapy, which include improvements in both cardiac prognosis and systemic outcomes. Further collaborative studies involving both cardiologists and endocrinologists are warranted.

: This article reviews the role of INSL3 as biomarker of Leydig cell function and its systemic action in testis-boneskeletal muscle crosstalk in adult men. Insulin-like factor 3 (INSL3) is a peptide hormone secreted constitutively in a differentiation-dependent mode by testicular Leydig cells. Besides the role for the testicular descent, this hormone has endocrine anabolic functions on the bone-skeletal muscle unit. INSL3 levels are low in many conditions of undifferentiated or altered Leydig cell status, however the potential clinical utility of INSL3 measurement is not yet well defined. INSL3 levels are modulated by the long-term cytotropic effect of the hypothalamic- pituitary-gonadal axis, unlike testosterone that is acutely sensitive to the stimulus by luteinizing hormone (LH). INSL3 directly depend on the number and differentiation state of Leydig cells and therefore it represents the ideal marker of Leydig cell function. This hormone is more sensitive than testosterone to Leydig cell impairment, and the reduction of INSL3 in adult men can precociously detect an endocrine testicular dysfunction. Low INSL3 levels could cause or contribute to some symptoms and signs of male hypogonadism, above all sarcopenia and osteoporosis. The evidence provided, suggested that the measurement of INSL3 levels should be considered in the clinical management of male hypogonadism and in the evaluation of testicular endocrine function. The monitoring of INSL3 levels could allow an early detection of Leydig cell damage, even when testosterone levels are still in the normal range.